Introduction and Part I of this series.

Few stories that begin, “Many Americans clueless…” can really be called “news.” Nonetheless, a recent study made headlines earlier this month by confirming what research has shown time and again: most people don’t know how many calories they supposedly burn. The 2010 Food & Health Survey by Cogent Research asked respondents (1,024 adults “nationally representative of the US population based on the Census”) to estimate how many calories someone of their age, height, weight, and activity levels “should consume” per day. Only 12% got within 100 calories +/- their Estimated Energy Requirement (or EER, the formula currently used by the USDA) and 25% wouldn’t even venture a guess. The remaining 63% were just wrong. This seems to pose a problem for the claim that publishing calorie counts on menus will improve public health. Logically, if people don’t know if they burn 10 or 10,000 calories in a day, which is the range of estimates collected in another survey, conducted in 2006 at the University of Vermont (full text with UMich login), knowing how many calories a particular menu item contains probably isn’t going to do them much good.

The new calorie publishing policy actually includes a provision to help address this problem—in addition to the calorie counts of all menu items, menus will also have to publish the average daily calorie requirement for adults (2,000 Kcal). New York City also attempted to address the problem of calorie ignorance when it instituted its calorie count requirement by launching an ad campaign aimed at drilling the 2000/day calorie requirement into people’s heads.

But that’s not the kind of calorie ignorance I’m concerned about. For one, I don’t think the success of calorie counts in reducing obesity or improving public health depends on people keeping strict caloric budgets. Enough people have internalized the belief they ought to eat fewer calories that the numbers could be useful as a point of comparison regardless of how many people can accurately estimate how many calories they supposedly burn based on their age, height, weight, and activity level. Even if you’re under the mistaken impression that you’re Michael Phelps, if your goal is to consume less energy, choosing between the 250-calorie sandwich and the 350-calorie one is a simple matter of figuring out which number is smaller. IF calorie counts were accurate, and they inspired at least some people to consistently chose lower-calorie items, and at least some of those people didn’t compensate for those choices by eating more later or being less active, and some of them continued to burn the same number of calories despite eating fewer of them, then the counts would actually have the intended effect. The magnitude of the effect might be small, but it would be in the right direction.

Of course, that’s a big “if.” I already addressed the first condition (calorie counts are often wrong), and will be looking at the next two (people don’t order fewer calories but if they think they have they are likely to compensate later) in more detail in later entries. The problem of most people not knowing how many calories they burn is related to the third condition—the mistaken assumption that people will continue to burn the same number of calories even if they reduce the number of calories they eat.

In other words, the problem isn’t that too few people know that the average adult probably burns something in the vicinity of 2000 calories per day. The problem is that metabolism varies. It doesn’t stick to the formula based on height, weight, age, and activity levels. Most people don’t know how many calories they burn because they can’t know, because it’s dependent on lots of factors that formulas don’t and can’t account for. And one of the things that usually causes people to burn fewer calories per day is eating fewer of them. This starts to get at one of the other reasons I don’t think posting calorie counts will have the desired effect: it’s true that eating fewer calories often leads to short-term weight loss, but the vast majority of people either get hungry and can’t sustain the energy deficit or their bodies adjust to burning fewer calories and erases the deficit. Either way, almost all of them regain all of the weight they lost, and often more. Read more

Introduction to this series here.

  When you see 450 posted, that might really mean 530. Or more.

Publishing caloric values right on the menu seems straightforward and transparent. The numbers offer what appears to be a simple way to compare items no matter how different they are based on what many people believe is, as Margo Wootan said, the “most critical piece of nutrition information.”  But even setting aside for a moment the issue of whether the number of calories should be the most important factor governing food choices or all calories are equal, there are problems with the numbers themselves.

Give or take 20%…but almost always give

According to a recent study at Tufts where a team of nutrition scientists led by Susan Roberts used a calorimeter to measure the actual caloric value of 39 prepared meals purchased at supermarkets and restaurant chains:

Measured energy values of 29 quick-serve and sit-down restaurant foods averaged 18% more than stated values, and measured energy values of 10 frozen meals purchased from supermarkets averaged 8% more than originally stated. Some individual restaurant items contained up to 200% of stated values and, in addition, free side dishes increased provided energy to an average of 245% of stated values for the entrees they accompanied. (Journal of the American Dietetic Association; full-text is subscription only—here if you have UM library permission)

As Roberts told Time, she decided to do the study because when she was trying to follow the diet advice in her own book, substituting prepared or restaurant meals, “the pounds stopped dropping off. Just as suspiciously, she always felt full” (more on the idea the fullness means a diet must be failing when I get to the issue of why calorie-restriction doesn’t work for long-term weight loss).

It’s worth noting that the results of the study didn’t reach statistical significance “due to considerable variability in the degree of underreporting.” However, they “substantially exceeded laboratory measurement error” and—as noted above—the average discrepancy was 8% or 18% higher, it didn’t even out. However, the average is actually within the Federal regulations—from the same Time article:

Federal regulations are strict about the accuracy of the net weight of a package of prepared food, which must be at least 99% of the advertised weight. When it comes to calories, the count can be a far bigger 20% off. The Federal Government plays no role in checking the calorie claims in restaurants, which means it's up to the states to handle the job — with the predictable patchwork results.

What Roberts’ research suggests is that calorie counts aren’t just wrong, they’re wrong in one direction. As anyone who’s ever tried to count calories knows, a difference of +18% could be devastating to a diet. Say, for example, you think you burn 2000 calories/day, like the supposed average American adult, and you’re trying to generate a ~250 calorie/day deficit through your diet. Assuming you continue to burn 2000 calories/day, that diet should make you lose about 1/2 lb per week or 26 lbs in a year. However, if you were actually eating 18% more calories than the 1750 you’ve budgeted, or 2065 calories/day, and the caloric algebra worked perfectly, you’d gain 6.8 lbs in a year instead.

Even if you’re being reductive, food is more than the sum of its parts

One factor that may work in the opposite direction: the method used to determine the caloric  content of food may systematically overestimate how much energy most people get from some foods. A quick primer on the calorie (most people who are reading this probably already know this, but since lots of people don’t): a nutritional calorie is a measure of the energy contained in food. The base unit, a gram calorie, is the amount of energy required to heat 1 gram of water 1 degree Celsius. A nutritional calorie is a kilocalorie (kcal) or “large calorie” (C), the amount of energy required to heat a 1 kg water 1 degree.

Here’s the part a lot of people don’t know: the caloric value on labels is calculated according to the “Atwater system” named after the USDA chemist William Atwater, who spent his career burning food and excrement (cue Bevis & Buthead laughter). Based on the formula Metabolizable Energy = Gross Energy in Food – Energy Lost in Secretions, Atwater came up with average energy values for each macronutrient: 9 Kcal/g for fat, 4 Kcal/g for protein, 4 Kcal/g for carbohydrates, and 7 Kcal/g for alcohol. For the purposes of nutrition labeling, even though fiber is technically a carbohydrate, it’s subtracted from the total carb weight before the calories are calculated since it’s not digested.

However, there appears to be considerable variation within macronutrients. Sucrose burns at a lower temperature than starch and isolated amino acids vary in their heat of combustion. Additionally, the Atwater system doesn’t account for differences in how macronutrients behave in when combined—for example, fiber seems to change the amount of fat and nitrogen that turn up in feces, which suggests that its effect on caloric value might not be entirely accounted for by simply subtracting fiber grams from the total carbohydrates. And, as you might expect, “variations in individuals are seen in all human studies” (Wikipedia).

The differences between estimated calories and the actual caloric value (as measured by a bomb calorimeter like the one Roberts’ team used in their study, which still might not correspond exactly to how food is turned to energy in the human digestive tract--I’m not entirely sure how calorimeters account for fiber given that fiber is combustible even though it isn’t digestible) might not be very large—but perhaps more importantly, the discrepancies probably aren’t consistent. The Atwater system is probably more accurate for some foods than others, and seems especially likely to overestimate the energy value of high-fiber foods and distort the differences between starchy and sugary foods.

That might help to explain the discrepancy seen in studies on nuts: in controlled nut-feeding trials, people eating more calories in the form of nuts don’t gain the weight that they should based on their greater energy intake. Additionally, they excrete more fat in their feces (Sabate 2003, American Journal of Clinical Nutrition). This is similar to another issue I mentioned in the introduction—not all calories are the same—but it’s not actually the same problem. Non-random variance in the reliability of caloric estimation means that even if all calories were the same, the numbers on the menus might not be accurate, i.e. the way we estimate calories might not correspond reliably to the amount of energy people actually derive from the food they eat.

So what?

Well, this means that there are (at least) two possible ways that providing consumers with “more information” in the form of calorie counts might actually lead to worse decision-making:

1) Even if people do base their decisions about what to order on the posted calorie counts, they might end up getting many more calories than they want and eating more than think they are.

2) Certain kinds of foods—including high-fiber foods and nuts, which might be “healthier” than items with lower posted calorie counts according to more holistic metrics—might have misleadingly high calorie counts based on the Atwater system. That could dissuade customers from ordering them or restaurants from offering them in favor of less “healthy” foods that may  have lower counts based on the Atwater system but actually provide more energy.

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Greens Fatigue

Since greens are one of the first crops you can harvest, the first weeks of most CSAs involve lots of them. In addition to the nettles, we’ve had lambsquarter (another “weed”), collards, chard, a variety of chois, and 1-2 bunches of kale every week.

I usually just sauté them with some garlic (and sometimes ginger or onion or a hot pepper) until they’re wilted and then I dress them with something acidic (lemon, white wine vinegar, rice vinegar) and something umami (tamari, crumbled bacon, grated parmesan). Salt and pepper to taste. That varies from great to mediocre. Sometimes the mild bitterness of the greens marries perfectly with the salty, rich, bright, savory accompaniments and it seems like exactly the kind of fresh, simple, delicious, nutrient-rich food that I joined a CSA to enjoy. Other times, it doesn’t matter if the greens are cooked in rendered bacon fat and topped with msg, it just tastes virtuous, and I mean that in the pejorative sense.

So this week, faced with two bunches of chard—one we didn’t manage to eat last week and another from the new box, I decided to try a classic preparation I’d heard of but never tasted.

Nothing Garlic, Butter and Cheese can’t fix

A gratin is just a casserole. It usually involves vegetables, pasta or meat tossed in a classic béchamel or flour-thickened milk sauce and topped with breadcrumbs and grated cheese. According to Wikipedia, the name comes from the French verb “gratter” meaning “to scrape,” which refers to the scrapings or gratings of bread or cheese that form the upper crust. Fun food idiom trivia: le gratin has the same metaphorical significance as “upper crust” in English. 

Baked mac & cheese is a gratin. So is the classic green bean casserole people make for Thanksgiving, even though most people let Campbell’s make the white sauce (which is basically what any flour-thickened cream soup is). But ironically, potatoes au gratin isn’t—or at least not the ones I’ve had, which are basically just potato slices in white sauce, or like a gratin without le gratin.

Chard gratin is about what you’d expect if you substituted the pasta in baked macaroni and cheese or the green beans in green bean casserole with cooked leafy greens—it’s creamy and savory and rich. It seems like a winter dish, especially because it requires that you turn on the oven, which I admit is sort of a drag in July, but it turned out to be exactly the sort of thing I was looking for to mix up my summer greens routine.

You could use any cooking green you like (epicurious has a nice visual guide to some of the more common ones). I can’t tell much of a difference between them after they’ve been wilted. Sure, some of them are a little more or less bitter and some stay chewier after cooking, but I wouldn’t want to have to identify them in a blind taste test. I assume the reason chard gratin is so much more common than spinach gratin (798000 google results compared to 164000) even though the latter is the more popular green by far is because casseroles are a handy way to use the stems as well as the leaves, and that’s just not an issue for spinach. Sadly, the stems don’t retain much of their spectacular color after cooking, but they are tender and mildly-flavored so it’s a shame to throw them away. They melt right into the casserole along with the softened onion and leaves.

I scanned a few recipes and then basically improvised based on what I had on hand. Precise instructions available below the jump, but here’s the short version you should feel free to adapt/improvise on at will: Blanche 2-3 bunches of chopped greens in boiling water, stems first for 2 minutes if using and leaves for another 1-3 depending on how hearty they are (spinach only needs a minute, kale or chard will take 3 to soften fully). Drain well. Then, sauté a fistful of chopped onions and/or garlic in some kind of fat, stir in a couple of tablespoons of flour and then gradually whisk in about a cup of milk. Season with salt and pepper and a little grated nutmeg, stir in some grated cheese if you want it, and add the well-drained greens. Spoon the mixture into a buttered baking dish, top with buttered breadcrumbs mixed with some herbs and grated parmesan, and bake (350-400F) until golden and bubbling (about 20 minutes).

To make it more like a main than a side, add some cooked pasta or a protein like leftover cooked meat, diced seitan, reconstituted tvp, or canned crab or tuna along with the cooked greens. You could also throw in some other vegetables, steamed or blanched unless they’re tender enough to eat raw. Following from the Thanksgiving classic, you could make a semi-homemade version by using a can or two of cream soup (probably onion and/or mushroom) instead of making a white sauce. Actually, with the green bean casserole in mind, I might try adding some crispy fried shallots to the topping the next time I make this. Which, if the CSA keeps up the current pace of the greens, will probably be very soon.  Read more

For this year’s patriotic, alcoholic Jell-O Jigglers, I decided to cut stars out of the bottom layer of Jell-O, fill the holes with a white gelatin mixture, and then replace the stars on the top layer and pour white gelatin around them. So the top and bottom layers both have blue and white stars and they sandwich a layer of red. Here’s the bottom, before I inverted it:

By the numbers:

• 2 small (3 oz) or 1 large (6 oz) box Berry Blue Jell-O
• 2 small (3 oz) or 1 large (6 oz) box red Jell-O (I used Strawberry)
• 8 packages (7 g each, about 2 oz total) plain gelatin
• 14 oz. (1 can) sweetened condensed milk
• 4 2/3 cups water (about 37 oz)
• 2 2/3 cups vodka (about 21 oz or 630 ml)
• 1 cup (8 oz) blue curacao
• 1 cup (8 oz) raspberry pucker
• 2/3 cup (5.3 oz) triple sec

That means it’s 11-12% alcohol or ~23 proof (107.3 oz total, 12.4 oz of which are alcohol—21 oz vodka @ 40% + 16 oz liqueur @ 15% + 5.3 oz liqueur @ 30%). So it’s roughly comparable to most wine or mixed drinks and approximately 18-27 servings of alcohol.

Layer #1: BLUE

Whisk together the first color of Jell-O (6 oz.) with 2 packages of plain gelatin. Add 2 cups boiling water and stir to dissolve. Cool slightly (10-15 min) and add 1 cup vodka and 1 cup clear or matching liqueur up to 40-proof (I only had 2/3 cup blue curacao so I added a little of the red pucker, which gave it a slightly midnight hue, and some triple sec). Chill until set—at least 30 minutes.

If your refrigerator isn’t level—mine isn’t, you can stick flat things under the corners to try to get the Jell-O to set in an even layer. I used pieces of individually-wrapped American cheese. 

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