Category Archives: hfcs

HFCS Follow-up: What the Rats at Princeton Can and Can’t Tell Us

Ed called my attention to last week’s press release about the study at Princeton currently getting some mass media attention. The press release claims:

Rats with access to high-fructose corn syrup gained significantly more weight than those with access to table sugar, even when their overall caloric intake was the same. 

i know it's a squirrel, not a rat. apparently no one's gotten a rat to do this and then circulated it with the right keywords to match my google search. this image likely not original to: http://ybfat101.com/notyourfault.shtmlThat’s pretty surprising, given that other studies have suggested that there is no difference between HFCS and sucrose. The Princeton study doesn’t offer a definitive explanation for the difference they found, but they suggest that it may have something to do with the slightly greater proportion of fructose in the HFCS.

As I noted in the first post on high-fructose corn syrup, HFCS-55, which is the kind used in soft drinks and the Princeton study, has roughly the same proportions of fructose and glucose as table sugar. Table sugar, or sucrose, is composed of fructose bonded to glucose so it’s a perfect 50-50 split. HFCS-55 contains 55% fructose, 42% glucose, and 3% larger sugar molecules. There’s a lot of evidence that fructose is metabolized differently than glucose, and may promote the accumulation of fat, especially in the liver and abdomen. Indeed, that’s why I believe that agave nectar is probably nutritionally worse than table sugar. Still, I’d be pretty shocked if a 5% increase in fructose could produce a statistically significant difference in weight gain, unless the rats were eating nothing but sugar-water. And they weren’t—in both of the experiments reported in the original study, the rats had access to unlimited “standard rat chow,”

Experiment 1: Rats Who Binge?

In the first experiment, 40 male rats were divided into four groups of ten. All of them had 24-hour access to rat chow and water. Group 1 was the control, so they just had chow and water. Group 2 had 24-access to an 8% solution of HFCS (.24 kcal/mL), which the press release claims is “half as concentrated as most sodas”. Group 3 had 12-hr access to the same HFCS solution. And Group 4 had 12-hr access to a 10% solution of sugar dissolved in water (.4 kcal/mL), which the press release claims is “the same as is found in some commercial soft drinks.” The two things of note so far are that none of the rats had 24-hr access to sucrose-sweetened water, and that the concentration of the sucrose was nearly 2x that of the HFCS syrup.*

Why the 24 hr vs 12 hr groups? According to the study:

We selected these schedules to allow comparison of intermittent and continuous access, as our previous publications show limited (12 h) access to sucrose precipitates binge-eating behavior (Avena et al., 2006).

In other words, they fed the sucrose group on a schedule that they already knew would cause binging. And they didn’t include a 24-hr sucrose group to control for that.

That helps to explain the results: the rats that had 24-hr access to HFCS-water gained less weight than either the rats who had 12-hr access to sucrose-water or the rats that had 12-hr access to HFCS-water. So according to the experiment, it’s better to consume some HFCS than it is to binge on sugar (not, obviously, how they chose to frame it in either the formal write-up or the press release).

Princeton rats

The only difference between the four groups in the first experiment that was statistically significant at a p<0.05 was between the rats who got chow only and the rats who got 12-hr HFCS. There was no statistically significant difference between the rats who had 12-hr access to sucrose-water and the rats who had 12-hr access to HFCS-water. There wasn’t even a significant difference between the rats who had 24-hr access to HFCS-water and the chow-only rats. So the only basis for the claim in the press release that HFCS is worse than sucrose is the fact that the rats with 12-hr HFCS got a “significant” amount fatter while the 12-hr sucrose rats didn’t. Even though the 24-hr HFCS rats didn’t either.

I am not the only one who’s picked up on this—both Marion Nestle (a vocal critic of the food industry) and Karen Kaplan (not, as far as I can tell, a shill for the Corn Refiners Association) also dispute the claim that this research demonstrates anything conclusive about HFCS vs. sucrose. The lead researcher replied to Nestle’s post, and rather than addressing the discrepancy between the 12-hr and 24-hr HFCS groups, he merely corrects her assumption that the 24-hr rats should be fatter:

There have been several studies showing that when rats are offered a palatable food on a limited basis, they consume as much or more of it than rats offered the same diet ad libitum, and in some cases this can produce an increase in body weight. So, it is incorrect to expect that just because the rats have a food available ad libitum, they should gain more weight than rats with food available on a limited basis. –Bart Hoebel

Which just makes it all the more baffling why they didn’t include a 24-hr sucrose group. Additionally, according to their results, binging or “consuming more” doesn’t explain the results, because:

There was no overall difference in total caloric intake (sugar plus chow) among the sucrose group and two HFCS groups. Further, no difference was found in HFCS intake and total overall caloric intake in the groups given 12-h access versus 24-h access. Both groups consumed the same amount of HFCS on average (21.3±2.0 kcal HFCS in 12-h versus 20.1±1.6 kcal HFCS in 24 h), even though only the 12-h group showed a significant difference in body weight when compared with the control groups.

The only explanation they offer for these results is the slight difference in the amount of fructose the rats in the HFCS and sucrose groups consumed. But even that relies on the idea that the HFCS rats did not feel as satisfied by their sugar water and compensated by eating more:

…fructose intake might not result in the degree of satiety that would normally ensue with a meal of glucose or sucrose, and this could contribute to increased body weight.

Unless satisfaction itself makes rats thinner.

Experiment 2 (Males): Wait, Where’s the Sucrose?

In the first part of the second experiment, 24 male rats were divided into three groups of eight. Again, all three had unlimited chow and water. Group 1 had 24-hr access to the HFCS-solution, Group 2 had 12-hr access to the HFCS-solution, and Group 3 was the chow-only control. Sucrose, you’ll note, drops out entirely. According to the study:

Since we did not see effects of sucrose on body weight in Experiment 1 with males, we did not include sucrose groups in this long-term analysis in males.

But there were no effects of HFCS on body weight on the 24-hr schedule! The omission of sucrose from this experiment makes as much sense as the omission of a 24-hr sucrose group in the first one. The lead researcher’s reply to Marion Nestle’s criticisms offered no further clarification about this choice. 

We explain in the article that we purposefully did not compare HFCS to sucrose in Experiment 2 in males, because we did not see an effect of sucrose on body weight in males in Experiment 1.

This study went on for 6 months instead of 2 months and, as the table above shows, the groups with both 24-hr and 12-hr access to HFCS-water gained a significantly greater amount of weight than the chow-only rats. This time, the 24-hr HFCS rats gained more weight than the 12-hr HFCS rats.

Experiment 2 (Females): Sucrose is back (still only 12-hr)! But chow is limited.

In order to “determine if the findings applied to both sexes,” they also ran a slightly different version of the second experiment on some female rats (n unknown). The control group, as usual, got unlimited chow and food. Group 1 got 24-hr access to HFCS-water. The remaining two groups got 12-hr access to chow (“to determine if limited access to chow, in the presence of HFCS or sucrose, could affect body weight”) and either 12-hr access to HFCS-water or 12-hr access to sucrose-water. Yeesh. How about testing one thing at a time, guys?**

So this time, only the rats with 24-hr access to HFCS gained a significantly greater amount of weight than the chow-only rats, which flies in the face of the claim that rats with limited access to a palatable food eat more. And the 12-hr sucrose rats actually gained slightly more weight (though not a statistically significant amount) than the 12-hr HFCS rats.

In other words, the findings in the three studies were completely inconsistent. For male rats in the short term, 12-hr access to HFCS induces significant weight gain but 24-hr access to HFCS does not. For male rats in the long term, both 12-hr or 24-hr access to HFCS induces significant weight gain, but they didn’t test sucrose. For female rats in the long term, only 24-hr access to HFCS with unlimited chow induces significant weight gain and limited chow, HFCS, and sucrose do not. And yet, based on this, they claim:

In Experiment 2 (long-term study, 6–7 months), HFCS caused an increase in body weight greater than that of sucrose in both male and female rats. This increase in body weight was accompanied by an increase in fat accrual and circulating levels of TG, shows that this increase in body weight is reflective of obesity.

Despite the fact that Experiment 2 didn’t even test the long-term effects of sucrose consumption on male rats, and 12-hr HFCS (albeit with limited chow) didn’t cause significant weight gain in female rats.

As Usual: Needs More Research

Based on the results of all three experiments, they conclude:

Rats maintained on a diet rich in HFCS for 6 or 7 months show abnormal weight gain, increased circulating TG and augmented fat deposition. All of these factors indicate obesity. Thus, over-consumption of HFCS could very well be a major factor in the
“obesity epidemic,” which correlates with the upsurge in the use of HFCS.

Despite the fact that obesity has also increased in many countries where HFCS is virtually never used, like Australia. According to a 2008 USDA paper:

Australia and the United States have a high and rising prevalence of obesity. They have opposite sugar policies: virtually no distortions affect Australia’s use of sugar, whereas sugar policy in the United States taxes sugar use. Sugar consumption per capita in Australia has been flat from 1980 to 2001, after which it increased by 10%-15%. Sugar is the major sweetener consumed in Australia.

The fact that the experiment doesn’t seem to show that HFCS is necessarily worse than sucrose doesn’t mean the findings aren’t intriguing. I really do want to know, for example, why rats with 12-hr access to HFCS gain more weight in the short term than rats with 24-hr access to HFCS, but the 24-hr HFCS rats gain more in the long term. And if, as they claim, the rats in all the groups consumed the same number of calories—which Nestle doubts because, "measuring the caloric intake of lab rats is notoriously difficult to do (they are messy)”—why were there any differences at all at the end of the trials? If none of the rats are eating more (and indeed, it seems that in some cases the HFCS rats were eating slightly less), what is the mechanism causing them to gain more weight, at least on some feeding schedules?

Does the concentration of the sugar have anything to do with it? In his reply to Nestle, Hoebel says:

Eating sucrose does not necessarily increase body weight in rats, although it has been shown to do so in some studies, usually employing high concentrations of sucrose, such as 32%. Our previously published work, has found no effect of 10% sucrose on mean body weight. At this concentration, rats seem to compensate for the sucrose calories by eating less chow.

I want to know if that’s true for HFCS as well. And did the difference in the concentrations of the HFCS and sucrose drinks have anything to do with the difference in the rats’ weight in this study?

Or does it maybe have something to do with sucrase, the enzyme that splits the fructose and glucose in table sugar? From what I’ve read, sucrase is present in the human digestive tract in sufficient amounts that it doesn’t rate-limit the absorption of those sugars in sucrose compared to the consumption of free fructose and glucose. But is it somehow involved in metabolism or appetite-regulation?

So rather than answering any questions about HFCS vs. table sugar, this really just raises a lot of new ones.

*It’s also not clear why they gave them different concentrations of sweetener. You’d think they would make them both soda-strength, or at least calorically equivalent.

**The failure to control for multiple variables does, in fact, complicate their ability to make any conclusions about gender difference:

In the present study, male rats maintained on 12-h access to HFCS also gained significantly more weight than chow-fed controls, while female rats maintained on 12-h access did not. It is possible that this can be accounted for by the fact that these males had ad libitum chow, while the females had 12-h access to chow. It is possible that the lack of chow for 12 h daily suppressed weight gain and TG levels
that might have otherwise been elevated in the female 12-h HFCS access group. This would indicate an effect of diet rather than a gender difference.

Don’t Drink the Agave-Sweetened Kool-Aid Part II: What’s Wrong With Any High-Fructose Syrup

Who knew agaves grew in so many different flavors?

In the first post on agave nectar, I focused primarily on why it’s no more “natural” than high-fructose corn syrup, which is a delicious irony given how both sweeteners tend to be portrayed. But that isn’t necessarily a reason to avoid agave nectar. “Natural” is at best an imperfect heuristic for healthiness or environmental friendliness, and has no inherent relationship with deliciousness. But, as I also suggested in the first post, agave nectar is certainly no better health-wise than other sources of sugar, and the fact that it’s much higher in fructose than most sweeteners (70-90% vs. ~50%) gives me reason to believe it may actually be worse for your health than sucrose or HFCS-55.

So Don’t Drink the Agave-Sweetened Ketchup Either. Because That Would Be Gross.GRANOLA-WASHING

Perhaps the most baffling thing is how many people seem to think agave nectar doesn’t count as sugar. For example, the rave review of Wholemato Organic Agave Ketchup in Men’s Health, contrasts it with the “liquid candy” that is HFCS. And then implies that the even-higher-fructose agave-sweetened condiment is healthier than “fatty” butter (it’s like someone at Men’s Health was specifically trying to give me apoplectic fits): 

This ketchup forgoes the high-fructose corn syrup and uses agave nectar, preserving sweetness without clobbering your fries or hot dog with liquid candy…. Slather it on your sweet potatoes as an alternative to a fatty slab o’ butter.

Note: The review is only available on the Wholemato site because the “read more” link is broken, but I’m not inclined to think it’s a fabrication as the other links on their “buzz” page are legit and you can find nearly-identical, equally-apoplexy-inducing claims about Wholemato Ketchup at The Kitch’n, Girlawhirl, i like granola, and Well Fed Man, among others.

There are also people who claim to have given up sugar, but who still eat agave nectar. Some excerpts from the comment thread on Nicole MacDonald’s resolution to give up sugar in 2010:

Jennifer: I went sugar-free at 16 to help my psoriasis & still don’t have it, 8 years later .
I don’t miss it at all. If I want to make a cake or anything I will use agave nectar … you realise there are so many interesting & alive foods out there you can enjoy without compromising your health!! xx

Nicole: I have to admit that in the first few weeks I baked a lot using ingredients like honey, agave and brown rice syrup. Cookies are my favorite to make, and I have a long list of recipes on my blog to the right. I also drank a lot of flavored tea with honey added and that seemed to cure some of my cravings.

Beth: I stopped eating sugar last year and its worked out pretty well. As long as I can have natural sugars which are found in fruits, then I’m totally satisfied.

Not All Things That Occur Naturally In Fruit Should Be Consumed In Quantity. Like Cyanide.

Beth is certainly not alone in thinking that “sugars which are found in fruits” are healthier than other sugars. People are frequently resistant to the idea that fructose might be unhealthy because, as the name so conveniently reminds them, it’s found in fruit. Or, if they’ve been sold on the idea that HFCS is poison and fructose has something to do with that, they sometimes suggest that there must be different kinds of fructose. Take, for example, the comment by Dave on this post by ThursdaysGirl, which expressed some reservations about agave nectar:

[. . .] you say Agave is 70% fructose, ok, so that means that means a teaspoon of Agave (about 4 grams) has about 2.8 grams of fructose… Hmmm, a small tomato has about 2.6 grams of fructose in it, the same as a carrot!… so, by your ridiculous logic, you should run away from tomatoes and carrots as fast and as far as you can! OMG, never eat another tomato! And don’t even get me started on Apples!

Remember, HFCS, regardless of what the lying chemists say, is not a natural source of Fructose. It is a man made molecule. It is illegal to call High Fructose Corn Syrup “All Natural”. I wonder why… Agave can be found both All Natural and Organic!!! Small amounts of Fructose actually help metabolize Glucose better, plus its low glycemic, has natural inulin fiber which is amazingly beneficial [. . . .]

I would trust the Mayo Clinics recommendations as regards to High Fructose Corn Syrup… it is poison. But really, Apples, Carrots, Tomatoes etc all bad for you? Stop it.

It’s actually not illegal to call HFCS “natural.” The FDA has been notoriously unwilling to define “natural” aside from the essentially meaningless distinction between “artificial” and “natural” colors and flavors—which Eric Schlosser talks about extensively in Fast Food Nation (pp. 121-131). As of July 2008, HFCS is “natural” for the purposes of food labeling. You can read all about the ongoing legal debates here. However, that hasn’t stopped people from trying to differentiate “natural” fructose, like the stuff in fruit, from “chemically-produced” fructose, like the stuff in HFCS. The problem is that they can’t seem to agree which side the fructose in agave nectar is on.

As you might expect, the agavevangelists are on the side of “natural.” According to Kalyn’s Kitchen Picks :

It’s been a long time since I discovered a new product that rocked my world in the way agave nectar has done…. The sweet taste in agave nectar comes from natural fructose, the same sweetener found in fruit (not to be confused with high fructose corn syrup which has chemically produced fructose.)

On the other side, there’s Rami Nagel, whose Natural News article been widelycirculated and cited by people on both sides of the agave nectar debate. According to Nagel, agave nectar is composed of bad, man-made “fructose,” which he claims actually has a completely different chemical formula from the sugar in fruit, which he calls “levulose”:

We all know that the chemical formula for water is H2O: two hydrogens and one oxygen. The opposite would be O2H, which is nothing close to water. Likewise, man-made fructose would have to have the chemical formula changed for it to be levulose, so it is not levulose. Saying fructose is levulose is like saying that margarine is the same as butter. Refined fructose lacks amino acids, vitamins, minerals, pectin, and fiber. As a result, the body doesn’t recognize refined fructose. Levulose, on the other hand, is naturally occurring in fruits, and is not isolated but bound to other naturally occurring sugars. Unlike man-made fructose, levulose contains enzymes, vitamins, minerals, fiber, and fruit pectin. (Similar claims here and here)

However, levulose is just an alternate name for fructose. A search for “levulose” on Wikipedia automatically redirects to their fructose entry. ChemBlink claims they’re synonyms with the exact same molecular formula and structure:

levulose/fructose...not quite as catchy as tomayto/tomahto 

And even the earliest examples from the OED reveal that the terms are completely interchangeable: 

1897 Allbutt’s Syst. Med. III. 386 Cane sugar is partly left unchanged, partly converted into glucose and lævulose. 1902 Encycl. Brit. XXII. 721/1 Glucose and fructose (lævulose)the two isomeric hexases of the formula C6H12O6 which are formed on hydrolysing cane sugar.

With “levulose” eventually giving way to “fructose” by the the 1970s:

1974 Nature 10 May 194/3 Although it is true that some bacteriologists are extremely conservative in the names they use for carbohydrates, surely nobody now uses ‘levulose’…in preference to ‘fructose’ these days.

A PubMed search for “levulose” also turned up 30,398 articles about (surprise!) fructose. The twenty articles that actually had “levulose” in the title were almost all translations, mostly from German.

So no, there is no difference between “naturally occurring” and “chemically-produced” fructose (and if the fructose in HFCS is the latter, so is the fructose in agave). Nonetheless, Dave and Rami Nagel are both at least partially correct. Fructose/levulose may not contain enzymes, vitamins, minerals, fiber, and fruit pectin, but the fruits that contain levulose/fructose certainly do. And there’s no reason to believe that eating a small amount of agave nectar, say a teaspoon, with similar amounts of fiber, protein, and other nutrients as would be found in a tomato or carrot would have a different or worse effect on the body than the vegetables themselves.

Fructose and Your Liver

Just because fructose isn’t necessarily bad for you in the amounts present in most fruits and vegetables, that doesn’t mean it’s a healthier substitution for other sugars. The evidence from studies on humans is still pretty scant. However, in a 2008 study where 23 subjects got 25% of their caloric intake from either fructose-sweetened or glucose-sweetened beverages for 10 weeks, the subjects who drank the fructose-sweetened drinks showed signs of decreased insulin sensitivity (a sign of diabetes) and increased fat in their abdominal regions, especially around their heart and liver, which is associated with cardiovascular disease (here’s the study itself or a translation from WebMD).

We’ve known for over 50 years that fructose is metabolized differently than glucose. Once it enters the body, it’s taken up by the liver, so it doesn’t raise blood sugar levels as much as glucose. It bypasses the step that insulin regulates, so diabetics can digest fructose about as well as non-diabetics. Which initially sounds good, especially for diabetics; however, more recently, fructose has been shown to have the same effects as alcohol on the liver:

I won't pretend to understand everything that's going on here, except that it illustrates the various processes and feedback mechanisms that cause fatty liver disease. From “Fructose Takes a Toll” in the August 2009 Hepatology (login required)

As a recent article in Physiological Review notes:

Fructose was initially thought to be advisable for patients with diabetes due to its low glycemic index. However, chronically high consumption of fructose in rodents leads to hepatic and extrahepatic insulin resistance, obesity, type 2 diabetes mellitus, and high blood pressure. The evidence is less compelling in humans, but high fructose intake has indeed been shown to cause dyslipidemia and to impair hepatic insulin sensitivity.

So while probably harmless in small amounts, it’s certainly not a “healthy” sugar or a free pass to eat sweet things without potential/likely health consequences.

I’ll do a follow-up eventually about the claim that you can use less of it because it’s sweeter. There are lots of conflicting claims about how much sweeter it is and how much less of it you use that I’m still trying to sort out. So far, I’m not at all convinced that the small caloric benefit is a reasonable trade-off for the risks of increased fructose consumption. I’ll also address one final defense: at least in some applications and to some palates, agave nectar may taste better. I admit to being a little skeptical, but a friend has promised to arrange a blind taste-test of mint juleps made with agave nectar, simple syrup, and a 50-50 agave nectar/brown rice syrup blend. That won’t happen until the national day of mint julep drinking, which falls on May 1, 2010 this year. So, until then, I’m going to take a little break from reading and writing about agave nectar.

Don’t Drink the Agave-Sweetened Kool-Aid Part I: “Natural” my foot

UGH the subtitle. I really want Ms. Catalano to show me exactly where in "nature" she gets her agave nectar. Also, I find the use of "ultimate" to mean "exemplary" or "best" instead of "final" or "last" grating, but that's a petty battle against usage change that "Ultimate Frisbee" has clearly already won. Still, I like to think of it as "Frisbee for the End Days" Just as "wholesome" as any other hydrolyzed, refined sweetener. If you've been snarky about the Corn Refiners' Assn's recent "Sweet Surprise" marketing campaign, but have a bottle that looks like this in your cupboard, I have some delicious all-natural snake oil to sell you, good sir or madam.

This entry was nearly titled “Things That Might Not Kill You In Moderation But Certainly Won’t Make You Any Healthier Vol. I,” or “Hydrolyzed, Refined Sweeteners Masquerading as ‘Natural,’ Whole Foods,” but those seemed a little unwieldy. They do, however, capture the essence of the argument: agave is nutritionally no better than most other refined sweeteners, including high-fructose corn syrup (HFCS). If anything, it’s probably worse because it contains more fructose than table sugar or HFCS. It’s also no more or less “natural” than HFCS—it’s actually produced in a remarkably similar process that was first used on the fibrous pulp of the agave in the 1990s. While, as its proponents claim, the higher proportion of fructose has enabled people to call it a “low glycemic index sweetener,” sometimes alleged to be safer for diabetics and recommended by weight-loss programs like Weight Watchers, recent research suggests that large amounts of fructose aren’t healthy for anyone, diabetic or otherwise.

I mentioned agave nectar in passing in the HFCS post, but there’s enough conflicting information about it to merit its own post(s). A lot of the misinformation comes from agavevangelists, who can sometimes get a little sanctimonious about their avoidance of the demon HFCS and preference for “natural” sweeteners. Even this Vegfamily article that concludes “the physiological effects of all [caloric] sweeteners are similar” nonetheless claims:

Given the choice between sugar, HFCS, and agave nectar, I’ll stick with organically-grown, unbleached cane sugar (evaporated cane juice) and organic raw agave nectar that are free of pesticides, herbicides, and chemical bleaching agents; not genetically engineered; and still retains some nutrients, as well as being vegan. Since HFCS is not available in organic form and is highly processed, I would never use it.

But agave nectar is just as processed as HFCS.

HFCS and Agave Nectar: One of These Things is Not Almost Exactly Like The Other

1910 magazine advertisement from http://goldcountrygirls.blogspot.com/2009/10/then-and-now-49-karo-syrup.html Like most starches, corn starch consists of large glucose polymers—70-80% the branched, non-water soluble amylopectin and 20-30% linear, soluble amylose. Normal or non-HFCS corn syrup, like Karo, is produced by breaking those polymers down into their constituent glucose molecules using acids, enzymes, and/or heat. For the history buffs: the acid hydrolysis of starch was first discovered because of the 1806 British blockade of the French West Indies. Napoleon I offered a cash reward for anyone who could come up with a replacement for cane sugar, and a Russian chemist named Konstantin Kirchhof found he could produce a sweet syrup from potato starch by adding sulfuric acid. The same process was first applied to corn in the mid-1860s, and gained popularity in the U.S. during the sugar shortages of WWI (source: The Oxford Encyclopedia of Food and Drink in America).

HFCS is produced by converting the glucose into fructose using an enzyme technology developed in Japan in the 1960s (detailed here). The resulting syrup, which contains up to 90% fructose, is then typically mixed with corn-based glucose syrup to produce HFCS-55 (the kind used in soft drinks, which has 55% fructose/45% glucose) or HFCS-45 (the kind used in baked goods, which has 45% fructose/55% glucose). Some people, like Cynthia commenting on Daily Candor, have suggested that the fructose and glucose in HFCS are absorbed into the bloodstream faster because they’re “free" instead of bound the way they are in the disacccharide sucrose, which is broken into glucose and fructose by the enzyme sucrase. Theoretically plausible, but apparently not true:

Sucrose is hydrolysed by brush-border sucrase into glucose and fructose.
The rate of absorption is identical, regardless of whether the sugar is presented to the mucosa as the disaccharide or the component monosaccharides (Gray & Ingelfinger, I 966, cited by H. B. McMichael in “Intestinal absorption of carbohydrates in man”).

I'm going to start refering to packaging like this as granola-washingJust like HFCS, agave nectar is produced by breaking down a plant-based polymer into its constituent sugars. In the case of agave, the relevant molecule is inulin, a fiber composed mostly of fructose units with a terminal glucose. Just like with corn and potato starch, there are different methods of hydrolyzing the sugars in inulin.  Blue Agave Nectar uses a thermic process. Madhava uses an enzyme process, just like HFCS.

Agavevangelists like to claim that agave nectar is a traditional sweetener used by native peoples, which appeals to the popular notion that the foodways of the past were generally healthier (e.g. Michael Pollan’s advice not to eat anything your great-grandmother wouldn’t recognize as food). Some, like Lynn Stephens of Shake Off the Sugar, merely note that the agave plant itself “has long been cultivated in hilly, semi-arid soils of Mexico.” That’s true, although it’s about as relevant as the long history of corn cultivation. Others claim that agave nectar itself has an ancient history. Flickr user Health Guy says of agave nectar: “It is 1-1/4 times sweeter than sugar, so you need less, and it has been consumed by ancient civilizations for over 5,000 years.”

Wrong. According to the website for Madhava Honey:

Agave nectar is a newly created sweetener, having been developed during the 1990’s. Originally, the blue agave variety was used. This is the same plant used in the manufacture of tequila. During the late 90’s, a shortage of blue agave resulted in huge increases in cost and a sweetener based on this plant became uneconomical. Further research was done and a method using wild agave was developed. Overcoming the language barrier between the Indians able to supply the nectar from the wild agave on their land and the Spanish speaking local manufacturer was the key that finally unlocked a supply of raw material and has led to our bringing this wonderful new product to market.

Still doing some native-washing (wild agave harvested by Indians who don’t speak Spanish—can’t you just feel the virtue?), but here’s what happens to the agave sap after harvesting, as described in the abstract of the 1998 patent issued for the production of fructose syrup from the agave plant:

A pulp of milled agave plant heads are liquified during centrifugation and a polyfructose solution is removed and then concentrated to produce a polyfructose concentrate. Small particulates are removed by centrifugation and/or filtration and colloids are removed using termic coagulation techniques to produce a partially purified polyfructose extract substantially free of suspended solids. The polyfructose extract is treated with activated charcoal and cationic and anionic resins to produce a demineralized, partially hydrolyzed polyfructose extract. This partially hydrolyzed polyfructose extract is then hydrolyzed with inulin enzymes to produce a hydrolyzed fructose extract. Concentration of the fructose extract yields a fructose syrup. (via Patentstorm)

Probably the healthiest sweetener pictured here and the one most shoppers in the market for a "natural sweetener" would be least likely to purchaseIt’s true that the corn used in HFCS is less likely than agave to be organically-grown, but you can get organic-certified corn syrup from the same manufacturer as the blue agave nectar pictured above and nutritionally, the main difference between that, the HFCS used in most processed foods, and agave nectar is the ratio of glucose: fructose. The regular corn syrup is 100% glucose, HFCS is usually 55/45 glucose/fructose, and agave nectar 56-90% fructose, depending on the plant and the process.

I’ve already talked a little about fructose vs. glucose here and here, but more coming soon in Agave-rant Part II concerning:

1) whether the fructose in agave is somehow better than, or indeed, different in any way from the fructose in HFCS

2) whether the fact that it’s sweeter than sugar makes it a lower-calorie alternative to sugar

3) whether its “low glycemic index” rating makes less likely to produce insulin resistance than table sugar and

4) whether it’s safer for diabetics

All of which people have claimed. I won’t keep you in suspense, especially given how long it may take me to put all of that together. The short answers are:

1) not in any nutritionally meaningful way

2) perhaps very slightly, but a <10 calorie/serving difference likely doesn’t make up for the increased risk of fatty liver syndrome and insulin resistance

3) no, it’s actually more likely to produce insulin resistance and

4) in miniscule amounts, perhaps, but recent trials involving diabetics and agave nectar were halted because of severe side effects.

Against the Soda Tax

awesome depth of field courtesy of Stephane Pompougnac http://www.flickr.com/photos/vox_efx/3063389109/

Although many states already tax soda (usually a fraction of a penny per ounce), a recent article in the New England Journal of Medicine on the potential benefits of a $0.01 per ounce tax on "soft drinks, energy drinks, sports beverages, and many juices and ice teas" has re-ignited the debate about whether or not we need a national soda tax. Back in July, Obama said a sin tax on soda was "an idea we should be exploring" in an interview with Men’s Health although in the recent panic about industry profits and personal liberties, the White House has been quick to note that they haven’t yet and have no plans to propose anything like it. 

Most people probably already know how the two sides shake out: promoters argue that soda makes people fat (which allegedly makes people sick and thus incurs social costs) so the tax would have the dual benefit of reducing the costs associated with obesity and generating money that would help cover health care costs (or balance state budgets). Opponents argue that soda isn’t morally distinct from many other elective behaviors that sometimes (but not always) contribute to disease and health care costs, and as soda consumption is inversely correlated with income, taxing it would disproportionately burden those least able to pay.

All of those are actually pretty complicated claims, some of which I’ll try to unpack below the jump but here’s the short version: even promoters admit that the tax isn’t likely to meaningfully reduce obesity or the diseases associated with it (note: not caused by it, as there’s still no reliable evidence that fatness causes any disease besides osteoarthritis, and anyone who wants to hear more about that should consult Paul CamposThe Obesity Myth, J. Eric Oliver’s Fat Politics, Glen Gaesser’s Big Fat Lies, and/or Michael Gard and Jan Wright’s The Obesity Epidemic). That means the only real argument in favor of the tax is that it would raise money. But everyone agrees that it would be a regressive tax. So unless you think that collective costs like state budget deficits and health care reform should be disproportionately shouldered by the poorest citizens, there is no good reason to support the soda tax (and this goes double for ill-considered suggestions that we just axe corn subsidies instead—also after the jump).

1. Even advocates claim the tax would only lower demand modestly. According to a study that hasn’t been published yet (referenced in the New England Journal of Medicine article) the price elasticity of soda is –0.8 to 1.0, meaning if the price of soda is increased by 10%, consumption should decrease by 8-10%. The $0.01 per ounce tax would actually increase the cost of a 20 oz soda about 20% (unless you’re buying it at a sporting event), so presumably it should decrease consumption by up to 20%. I’m a little skeptical about that, and am looking forward to seeing how they determined its price elasticity, but I sort of doubt that soda is "unit elastic" meaning the percent change in demand will always be approximately equal to the percent change in price. Unit elasticity usually relies on the assumption that a good is readily replaceable—perhaps they assumed that tap water serves all the same dietary, social, and psychological functions as soda? Or that regular soda drinkers will switch to diet if there’s a $0.15 to $0.20 incentive? Nonetheless, their simultaneous insistence that this tax would address state budget problems or fund health care in any meaningful way is predicated on the fact that it’s not likely to decrease demand significantly. Most soda consumers will be more than willing to pay another dime per can of soda.

2. Although sugary drinks have probably contributed to the relatively small average weight gain over the past few decades, no one really thinks soda alone is what’s making people fat. Even for people who might reduce their soda consumption as the result of a sin tax, The New England Journal of Medicine estimates (conservatively by their own admission) that people would probably compensate for an average of 25% of the lost calories by eating or drinking more of something else. If people rely on soda as a source of a "sugar buzz" or have what might be called an "addiction" to sugar, it seems likely that they would compensate with other sugars. Some might substitute with diet soda, but it’s worth noting that longitudinal studies suggest that people who drink diet sodas actually have a greater chance of being obese than people who drink regular sodas. The causal arrow is almost certainly obesity—>drinking diet soda and not the other way around, but if drinkers of diet soda are more likely to become obese than drinkers of regular soda, that certainly challenges the notion that soda is a necessary cause of obesity. The relationship certainly isn’t as linear as the relationship between cigarettes and smoking, which it’s often compared to. And proposed "twinkie taxes" that would levy other calorie-dense, low-satiety and vitamin-poor foods haven’t gained any political traction because just like soda, it’s possible to consume things like frappucinos, Doritos, Wonderbread, instant ramen, or "fast food" remain non-obese. Plus, unlike soda, each of those does contain nutrients generally recognized as desirable. Despite all the cultural stigma and personal shame associated with some "sinful" foods, the healthfulness and morality of most things we eat and drink turns out to be a little too tricky to legislate.

3. The idea that this tax would be limited to "sugary" drinks is almost certainly not going to work in practice. Restaurants and gas stations aren’t going to start charging a different price for their diet soda and unsweetened iced tea than they do for their regular soda and sweetened iced tea, especially when they have self-service soda fountains. While there’s actually nothing more objectionable about taxing unsweetened iced tea or diet soda than regular soda (less, probably, if the former are more likely to be consumed by wealthier people), there’s a good reason the supporters of the tax aren’t calling for it: there’s no moral defense of a tax on soda water or unsweetened iced tea. No one thinks plain soda water makes people fat or causes disease (okay, I’m sure someone somewhere does, but they probably also think crystals heal people and agave nectar is "natural" and microwaves communicate your private personal information to the aliens who abducted Kennedy). 

Some people, even those who are opposed to the tax like Katherine Mangu-Ward of Reason.com, have suggested that we could just eliminate corn subsidies instead. Mangu-Ward notes that the projected annual revenues from the soda tax are, coincidentally, just about equal to the subsidies we pay to corn farmers. Joe Weisenthal makes a similar suggestion over at The Business Insider.

The first problem with this idea is that, as I’ve mentioned before, the farm cost of the corn in soda is only 1.6% of the price. Less than 2 pennies of a $1.20 bottle of soda go to the farmers who grow the corn that becomes high fructose corn syrup. Even if the elimination of the subsidies doubled the price of HFCS, the cost of soda would only go up a cent or two.

The second problem is that not all subsidized corn becomes HFCS. Less than 12%, according to the National Corn Growers Association. Most of it, as anyone who’s seen King Corn or read Michael Pollan knows, is used to feed livestock (how much exactly is a little unclear; I’ve seen a number of claims that eighty percent of all corn grown in the U.S. is consumed by domestic and overseas livestock, poultry, and fish production, but those may be outdated because of the rise of ethanol. Still, the most recent stats I could find on the NCGA website claim that 42 percent of U.S.-grown corn is fed to domestic livestock. The upshot: a substantially larger part of corn subsidies go towards feedlot beef than soda).

Rather than having a comparable effect as taxing soda, Mangu-Ward’s plan is far more akin to a tax on feedlot beef. And that, more even than the power of corn growers, is what would make it politically impossible. Weisenthal mysteriously suggests that it would be politically easier to eliminate "any subsidies that go towards high-fructose corn syrup," as if the industry behind the most-produced crop in the country and all the industries that rely on it have less clout than the "soda industry."

For the record, I’m not opposed to higher beef prices on any moral or economic  or even nutritional grounds. I’m not convinced that corn-fed beef is a necessary part of a healthy diet (although nor am I convinced that it’s necessarily unhealthy either, as the effects of dietary saturated fat and cholesterol seem highly dependent on what else you eat them with), and I suspect that the mass production of cheap meat might contribute to a number of environmental and social ills. I am all for reforming the seemingly-outdated system of agricultural subsidies that encourages certain kinds of farming and discourages other ones, but honestly, I don’t know exactly what that reformed system should look like. And I doubt Mangu-Ward or Weisenthal do either. I suspect that simply eliminating subsidies for the commodity grown in the largest quantities is not the best way. And in any case, it wouldn’t increase the cost of soda, fund health care, or fix state budget crises. As ever, not all simple answers are best.

Things that won’t kill you Vol. 2: Fruit juice

This may seem like a strange thing to argue about, because the popular consensus still seems to be that juice is healthy. Jamba Juice markets itself as "the category-defining leader in healthy blended beverages, juices, and good-for-you snacks." They even use Jamba as an adjective to mean the opposite of high fructose corn syrup and trans-fats (adding those things to juice ""just wouldn’t be Jamba"), which again, constructs the brand as healthy vs. the demon poisons that make people fat. Even if it’s foolish to go looking for truths in advertising, I don’t think Jamba Juice’s branding generally occurs to people as a massive irony or lie. Advocates of banning or restricting soda vending machines in schools often claim that the soda should be replaced with 100% fruit juice with no added sugars, and for many people, a glass of orange juice still represents "part of a nutritious breakfast" strongly with desirable nutrients like Vitamin C.

The Case Against Juice

But a number of health trends have begun cast suspicion on juice, especially the (impartial and incomplete) shift from primarily low-fat to primarily low-calorie and low-carb dieting in mainstream weight-loss culture, and the growing concern about the role sugars (especially fructose) play in personal and national obesity.

On the low-calorie front, people who believe that losing weight or maintaining a healthy weight is all about the basic algebra of calories-in vs. calories-out often end up axing all caloric beverages from their diets because they have a bad satiety-to-calorie ratio—I mean, obviously, right? Fruit juice is just fruit with some or all of the filling fiber removed. If the goal is maximum satiety on minimum calories, you’re better off eating whole fruit and drinking water or artificially sweetened beverages.

On the low-carb front, people who believe that what’s important is not how many calories you eat but what kind are also going to see juice (and sometimes most fruits and vegetables as well) as "unhealthy." It does seem to be true that diets high in carbohydrates drive up insulin levels, slowing metabolism and encouraging the body to store fat. And the overwhelming majority of the calories in most fruit juices are in the form of carbohydrates. Some green vegetable juices have protein content approaching 50% of the carbohydrate content, but that just makes it 75% bad rather than 100% bad, at least as true carbophobes are concerned.

And finally, there are some non-carbophobes who might avoid juice because they’re wary of sugar qua sugar, rather than sugar qua carbohydrate. The carbohydrates in fruit juice primarily take the form of fructose—wikipedia has a handy chart of the kinds of sugars in common plant foods. It doesn’t seem like there’s a true consensus yet about whether or not fructose is especially bad—despite recent studies linking fructose to obesity, even within the medical community, some people still advocate fructose as a "low glycemic" sugar that’s better for diabetics. It basically all comes down to whether you think the fact that fructose is digested in the liver and doesn’t trigger insulin production is a good thing or a bad thing. To link it to other sugar purveyors: pro-agave nectar people should also think that fruit juice is healthy and people who think hfcs is bad because they think it’s "high fructose" compared to other sugars are, well, a) wrong, but b) should also be advocating hfcs-sweetened sodas over fruit juices, which are even richer in sugar.

Personally, I think the evidence that fructose in large amounts causes equivalent blood sugar spikes to other sugar, increased "bad" cholesterol and triglycerides and signs of insulin resistance compared to glucose, and can cause non-alcoholic fatty liver disease consumed in vast quantities suggests that it is certainly no better and possibly much worse for human health than glucose or sucrose. But "worse for human health" is relative, not absolute, and depends a lot on amount, kind, and context. 

What is health?

I’m generally convinced by the argument made by people like Gary Taubes that a diet composed of almost-exclusively proteins and fats might better represent the pre-agricultural, hunter-gatherer diet (as would cyclical feast and famine) and prevent carbohydrate-induced insulin resistance and fat storage. Jared Diamond makes some of the same points in Guns, Germs, and Steel. But the benefits of agriculture ultimately outweighed the costs—both for the species as a whole and measured by individual health metrics. In the immediate aftermath of the transition to agriculture, lifespans and average height decreased, but after a few thousand years, people depending on rice, corn, and wheat began to get healthier again

Does that mean carbohydrates are a healthier basis for a diet than proteins and fats? No. But it does mean that people can (and do) live very long lives uninterrupted by diet-based disease during which they are strong and energetic enough to physically do anything they want to do while eating a diet consisting substantially of carbohydrates. And I think that’s not a bad working definition of "healthy."

It seems to me that the debate comes down to a difference between ideas about nutritional "health" based on what might be theoretically optimal (for a very limited set of criteria), ideas about health based on potential pathology, and ideas about health based on actual health outcomes

Fear of juice is based on the first two—the idea that either people should eat as few carbohydrates as possible in pursuit of some sort of optimal diet, or that the fructose in juice will cause fatness (an aesthetic problem, not a medical problem) or disease and eventually death. Based on actual health outcomes, I think it would be almost impossible to make a case for the claim that drinking fruit juice—occasionally or regularly—is categorically unhealthy or the direct cause of disease or death.

In fact, things like fruit juice and hamburgers and Doritos, which can each be constructed as "unhealthy" are hard to entirely rule out of a "healthy diet." Even proponents of a soda tax generally agree that the only reason soda is a reasonable target is because it has no identified nutrients (what would happen if they fortified them, I wonder?).

The nutrient-density of juice is the primary reason for the long tradition of juice being regarded as a health food. If your concern is about essential vitamins and minerals (like many older models of nutrition, which people like Marion Nestle stand by) or consuming carbohydrates for fuel, which many physically active people still do, it’s hard to argue with the healthfulness of juice. I agree with Michael Pollan’s claim that popular beliefs about health often fall prey to "nutritionism," or the attempt to reduce food and nutrition to scientifically-identified nutrients and vitamins. At the same time, I don’t think you have to be brainwashed by the continued prevalence of nutritionism to believe there’s good evidence that many of the nutrients that scientists have identified are actually valuable or promote health and well-being (even if they’re not the only valuable aspects of food).

All juices are not created equal

The person who requested this entry was concerned specifically about fresh juices being portrayed as unhealthy, because they seem to have been smeared by concerns about packaged juices being just other source of dietary sugar.

While not all fruits lend themselves as readily to the production of refined sugars as sugar beets, some like apples, pears, and grapes can be turned into a nutrient-poor sweetener without most of the fruits’ color, flavor, or minerals and many fruit juices marketed as 100% natural fruit juices, like Juicy Juice, are sweetened with fruit juice that’s basically been turned into a sugar syrup. The nutritional distinction between those drinks and hfcs-sweetened soda is probably negligible regardless of whether your primary concern is calories, carbohydrates, sugar, or vitamins.

But the reason packaged juices often combined with fruit-based sugar is that many fruit juices aren’t actually that sweet on their own, or their sweetness is offset by the intensity of the flavor, as anyone who’s ever tried 100% cranberry or concord grape or cherry or blueberry juice knows. The fresh juices you can get at juice bars or make at home are calorie-dense, but they’re also extraordinarily nutrient dense and not likely to be consumed in quantity or alongside meals. They’re more often enjoyed on their own, like a snack, particularly after a workout—basically just like fruit. When you leave in some of the pulp, it becomes even less nutritionally distinct from fruit, and when you include vegetable juices or the juices of things like wheatgrass and ginger which are difficult or unpleasant to eat raw, you may be enjoying something that could, by some criteria, be healthier than a piece of fresh fruit.

Some juices even have pretty well-established medicinal uses. Cranberry juice, for example, can help prevent and cure urinary tract infections (that study notes the existence of "diet" cranberry juice, which I’d never heard of, but now that I have I wonder why there aren’t more "diet" juices sweetened with artificial sweeteners rather than pear or grape juice-sugar. Not that those would necessarily be "healthy" by everyone’s standards, especially given the links between saccharin and cancer and suspicions about the healthfulness of aspartame and sucralose…)

Ultimately, while I don’t think even the occasional hfcs-sweetened Capri Sun is incompatible with a "healthy" diet and life, I think it’s unreasonable to conflate fresh juice without added sweeteners with juices sweetened with refined juice-sugar. I guess people trying to eat an "optimal" diet a la Gary Taubes should avoid all juices, fresh or no, but I don’t envy them their carbohydrate-less life, nor am I convinced that the total deprivation of many foods that have aesthetic, gustatory, social and/or cultural value is necessarily "healthy" or "optimal" either. For the vast majority of people who think fruit and vegetables are part of a healthy diet, fruit juice and especially fresh fruit juice should also pass muster as a "healthy" choice especially when consumed in moderation, which I suspect fresh fruit juices usually are.

Things that won’t kill you Vol. 1: High-fructose corn syrup

Confession: I not only avoided high-fructose corn syrup (hfcs) until about a year ago, I was actually skittish about fresh corn for a while after my first encounter with Michael Pollan in The New York Times Magazine (or it might have been this article). I stopped eating corn tortillas and frozen corn kernels and felt vaguely panicky about the possibility that I was consuming hfcs in condiments and sandwich bread when I ate out, even if it would have only been tiny amounts.

Now that I’m over it, I sometimes have a hard time remembering what was so scary about the idea that there was corn in everything I was eating, an idea that was obviously ludicrous anyway because I was a vegetarian who mostly ate food prepared at home from whole, fresh, non-corn ingredients. But looking back at the articles linked above, they are pretty ominous. Even though Pollan notes that a corn-based diet has been the norm in Mexico for centuries without any apparent ill effects, and the story he tells about the "cornification" of the American diet is too complex to be a nefarious plot designed to kill us all, it’s clear that he thinks the amount of corn Americans eat on average is a Bad Thing. Sure, it may rely on innocent accidents of nature, like the uniquely efficient way corn fixes carbon during photosynthesis and and the great distance corn pollen has to travel to reach the style, but it’s also reliant on much more insidious developments: synthetic pesticides and fertilizers, an arcane federal farm subsidy systems that turned corn into "a welfare queen," agribusiness giants with seed patents on genetically-modified strains, giant livestock feeding operations that use antibiotics to keep cows alive because eating corn makes them sick, and food manufacturers who profit from getting people to buy cheap food in ever-increasing quantities. Eating corn in any form may seem like a way of giving in to all of that or even supporting it.

So although I did a fair bit of eye-rolling when I read about people avoiding sweet corn at their farmer’s markets this summer or feeling "corn guilt" when they eat popcorn, it’s worth remembering that I was one of them not so long ago.

HFCS paranoia is not primarily an issue of ethical consumption

It’s not that many of those concerns are invalid—it’s true that most corn relies on a lot of synthetic fertilizers and pesticides, that much of it is grown using genetically modified seeds with patents held by huge corporations that have been known to sue farmers when corn with their patented genes end up in their fields, that cows fed diets of corn get sick and are more susceptible to diseases like e coli that can threaten humans. But it’s also far from clear that refusing to eat ketchup containing high fructose corn syrup is an effective means of changing any of that or even primarily motivated by the desire to change those things.

Although people like Pollan have made a big deal about corn sweeteners being artificially cheap due to farm subsidies, the actual farm cost of hfcs in the food products we buy is so minimal that even if subsidies were eliminated entirely, it might not affect portion sizes or consumer demand at all. Even in soft drinks, which are by far the most demonized hfcs delivery system, hfcs represents just 3.5% of the total cost of manufacturing. The corn content, the only part actually affected by farm subsidies, is only 1.6 percent of the price (based on US Department of Commerce data). A comparison between the U.S., Australia, the UK, and France, all of which have different sugar policies but similar consumer prices, show no pattern in the relationships between how cheap sugar is, how much of it people eat, or how fat on average they are (which most people wrongly assume is a reliable measure of health outcomes, but I’ll tackle some other time).

Pollan’s formal case against hfcs relies primarily on arguments about price and prevalence, but that doesn’t really explain the kind of paranoia his books and articles have helped inspire about eating corn and/or hfcs. Not buying and eating something because it’s too cheap just isn’t the kind of consumer behavior that spreads the way hfcs-phobia has. Nor is this some sort of mass avoidance of all added or refined sugars, or brands like Snapple and Pepsi wouldn’t be running huge campaigns to advertise soft drinks containing only "natural sugar."

Instead, people have latched on to the implication, which isn’t supported by any data I can find, that hfcs is nutritionally worse than other sugars. The hfcs paranoia isn’t caused by the idea that hfcs might be unwisely or unfairly subsidized or that pesticides used to produce corn are poisoning waterways or anything related to feeding corn to cows. The fear is that hfcs might be some kind of demon poison that makes people fat.

The confusing part: "high fructose" isn’t actually high fructose

The idea that hfcs is worse than other sugars seems to be primarily reinforced by research about how fructose is metabolized. Just last April, an article about a study comparing drinks sweetened with fructose and  glucose in the New York Times began:

Some research has suggested that consumption of high-fructose corn syrup, used as a sweetener in a wide variety of foods, may increase the risk of obesity and heart disease. Now, a controlled and randomized study has found that drinks sweetened with fructose led to higher blood levels of L.D.L, or "bad" cholesterol, and triglycerides in overweight test subjects, while drinks sweetened with another sugar, glucose, did not.

Things like this get reported all the time. However, the very last sentence of the article quotes another biochemist:

The study did not test high-fructose corn syrup, he said, and judgments should not be made about it from the findings.

Not that that stopped the author from leading with the useless, ambiguous claim about a supposed link between hfcs and obesity, but surely this deserves a little more attention: yes, fructose alone seems to cause more insulin resistance and weight gain in both rats and people than glucose alone. But high fructose corn syrup is only "high fructose" relative to normal corn syrup, which is 100% glucose.

The kind of hfcs used in most food processing, including soft drinks, is hfcs-55, which is approximately 55% fructose and 45% glucose, or almost identical to sucrose, which is about 50/50. Another kind, hfcs-42, is used in the manufacture of some baked goods, and if fructose is really worse, that would make that kind of hfcs healthier than cane sugar. Indeed, studies comparing the consumption of hfcs to sucrose have shown no differences in metabolic responses (or energy or macronutrient intake) at all.

The argument that hfcs is somehow responsible for the obesity epidemic relies entirely on correlations between the rise of hfcs in food manufacturing in the 1980s and the rise in national rates of overweight/obesity (and the exponential rise in concern about fatness). Pollan’s case against hfcs amounts to a gut suspicion that:

It’s probably no coincidence that the wholesale switch to corn sweeteners in the 1980’s marks the beginning of the epidemic of obesity and Type 2 diabetes in this country.

Of course, this fails to account for the simultaneous increases in obesity in many other countries, perhaps most notably Australia, where obesity rates rival or even exceed those in the U.S., but sugar is the primary sweetener. It’s not that he’s totally wrong; it does seem probable that U.S. farm subsidies and the cheap price of highly-palatable, nutrient-poor, calorie-rich, primarily carbohydrate-based foods is one factor driving the relatively small increases in the average American’s weight since the 1970s. And the history of corn cultivation and agricultural policy has something to do with that. But there’s no reason to think that hfcs is uniquely responsible for the "obesity epidemic." After all, if it weren’t for subsidies and tariffs that keep the price of sugar artificially inflated, which are the result of a different set of biological, historical, and political contingencies, it would be just as cheap. 

Ultimately, hfcs is just another source of sugar, nutritionally no different from cane sugar, and way better than agave nectar if you’re concerned about fructose. It might be slightly worse than things like honey (esp. raw) and maple syrup (esp. grade B or lower) if you’re interested in vitamins and minerals. (This is all assuming the hfcs in question contains mercury, but that’s sort of another story altogether).

That doesn’t mean hfcs is  "natural," a word which has virtually no meaning when it comes to food labeling anyhow, but then, if "natural" is the alternative to "processed," no sweeteners are. Agave nectar must be filtered, hydrolyzed, re-filtered, and concentrated before it can be used as a sweetener. Refined cane sugar is purified with phosphoric acid and calcium hydroxide, and sometimes whitened using bone char which is why some vegetarians and vegans refuse to eat it.

The upshot is there’s no reason to believe that hfcs is any worse for you than sugar or much worse for you than any other sweeteners, and there’s certainly no reason to believe that a little bit here and there in a favorite condiment or even the occasional soda is going to hurt you.

Later in this series: I’ve gotten a request to weigh in on fruit juice, and will try to do that soon. And someday I’ll get around to msg, as promised before.