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

Posted by Margot | Filed under:
Mar 29 2010

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. Read more

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

Posted by Margot | Filed under:
Mar 10 2010

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. Read more

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

Posted by Margot | Filed under:
Sep 17 2009

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.  Read more