Saturday, July 25, 2009

Lost in the Supermarket

I have found that a good place to have a complete nervous breakdown is a supermarket. There are a number of reasons for this. First of all, there are far too many choices. While attempting to buy breakfast cereal, I’ve been known to fall to the floor in Price Chopper, curl into the fetal position, and start weeping uncontrollably. Does the universe really need more than one type of Frosted Flakes? Rice Krispies? (Snap, crackle, and freak out.) And the first person who can tell me that there is any difference between Wheat Chex, Rice Chex, and Corn Chex is going to get beaten with an ear of corn.

When trying to pick out toothpaste, I can make Hamlet look like the very model of decisiveness and action. Tartar control, or not tartar control? That is the question. It’s reached the point where I blindfold myself, run into the toothpaste aisle, grab a tube of something at random, and flee as quickly as possible. Okay, so once I accidentally grabbed a tube of Preparation H instead. The only trouble is I think my teeth are shrinking. But I digress.

For a good exploration of why consumer products companies are making us all completely insane and miserable, I recommend a good book by Barry Schwartz called The Paradox of Choice: Why More is Less.)

Tangentially, I was once in Price Chopper and saw a sign that advertised “semiboneless leg of lamb.” Semiboneless? Isn’t that like “slightly pregnant”? I mean, it’s a binary state—yes/no. On/off. 0/1. Bone/no bone. Must this be so difficult?

But for true supermarket anxiety, nothing can beat trying to read nutrition labels. I will admit that I do pay fairly close attention to comparing food labels, and I think by now I could easily obtain a Ph.D. in Advanced Mathematics. The trick is to find the number of calories per serving, find out what they consider a serving, and then--and this is the tricky part--determine how far removed from reality their estimate of a serving size is.

I was looking at a box of red beans and rice and according to the label, it contained only 190 calories per serving. Hey, that’s not bad! However, they considered a “serving” to consist of something like three grains of rice. Since I’m not a sparrow, I had to then work out what a realistic serving size for a human would be and then do the math.

Then there is comparing one product to another. The red beans and rice has 190 calories per serving, but it considers a serving to be 1/4 cup, but the rice pilaf has 150 calories per serving, but it considers one serving to be 1/3 cup. Okay, the lowest common denominator is 12... Help me, Spock!

Ah, but then there’s the Pasta-Roni option. The Olive Oil and Garlic Pasta has 220 calories per serving, but a serving size is 2.5 oz. Okay, 8 oz. per cup, four quarts in a gallon, 30 days hath September... The label also tells me that there are about 50 fewer calories “as packaged” than “as prepared.” That’s useful, because it lets me know that if I chomped down the dry pasta and had a few spoonfuls of the powdered mix, I can save some calories.

Oh, but the Three-Cheese Pasta has... And it’s usually at this point that the manager has me escorted out of the store, as I have been in the rice and pasta aisle for about 12 hours.

All that is bad enough, but then I read an article in New Scientist this week that found that the methodology used to determine nutritional information may be faulty--and could be off by as much as 25%! Well, that’s good to know. I have also discovered that screaming and pounding the floor with one’s fists is a good aerobic workout.

How do they determine how many calories are in a food anyway? In the same way that many of us prepare our meals: they burn it.

First of all, a “calorie” is a measure of heat. Specifically, it is a measure of the amount of heat that will raise the temperature of 1 gram of water from 14.5° to 15.5° Celsius. Making things even more confusing is that the “calorie” used by dietitians and nutritionists is actually a kilocalorie, or 1,000 calories, also referred to as a Calorie (with a capital C). (Yes, they hate us.) So if a food is said to have 200 Calories it actually has 200,000 calories. It would be pretty funny if labels listed the actual lowercase-c-calorie counts of foods! Well, maybe not funny ha-ha...

Anyway, the original method for measuring calorie (or Calorie) counts was developed by an American chemist named Wilbur O. Atwater. He used what was known as a “bomb calorimeter,” basically a fireproof container hooked up to a thermometer. He would put a food—say, a turkey leg or a piece of beef—inside it, burn it, and measure how much energy was released. Maybe it’s just me, but if I had been Atwater’s lab assistant, I would be burning with insatiable curiosity to put a human head in the bomb calorimeter. I mean, maybe if the Donner Party had had accurate nutritional information things might have tuned out differently.

But I digress.

As we all know far too well (particularly on long road trips) not everything in a food is absorbed by the human body, and the process of digestion itself burns calories (about which more later), so Atwater needed to add some extra steps, and through his research developed a series of tables that corrected the raw calorie counts based on type of food (protein vs. carbohydrate, for example). His research, while refined a tad over the years, is still the gold standard for generating nutrition label information. (A little bit of trivia for you: Atwater’s daughter Catherine married the famous economist John Kenneth Galbraith. It’s not particularly interesting but I thought I’d just throw it out there.)

Today’s calorimeters are a bit more advanced. As this article in Slate explains:
food laboratories often freeze their samples in liquid nitrogen and then blend them into a fine, monochromatic powder that can then be used in a variety of chemical analyses. In a Kjeldahl analysis, for example, lab techs remove nitrogen from the food powder and then use it to calculate the amount of protein the sample contains. A hexane extraction can gauge the amount of fat. Carbohydrates are usually measured by difference—they’re what is left over when you remove everything else.
Funny, I usually cook in that exact same way.

The methods developed by Atwater were useful, but new research suggests that it is still subject to a great deal of error. From the New Scientist article:
Nutritionists are well aware that our bodies don't incinerate food, they digest it. And digestion - from chewing food to moving it through the gut and chemically breaking it down along the way - takes a different amount of energy for different foods. According to Geoffrey Livesey, an independent nutritionist based in Norfolk, UK, this can lower the number of calories your body extracts from a meal by anywhere between 5 and 25 per cent depending on the food eaten. "These energy costs are quite significant," he says, yet are not reflected on any food label.
Take fiber (please!):
As well as being more resistant to mechanical and chemical digestion than other forms of carbohydrate, dietary fibre provides energy for gut microbes, and they take their cut before we get our share. Livesey has calculated that all these factors reduce the energy derived from dietary fibre by 25 per cent - down from the current estimate of 2 kcal per gram to 1.5 kcal per gram
Other nutrients such as protein are also subject to correction--and while this may not seem like a lot, it can add up over time. That is, as fat. The good news, I suppose, is that food labels tend to overstate the number of calories, although not consistently, and may give the impression that something that is actually healthier (the New Scientist article uses an oatmeal bar) has more calories than something unhealthier (a brownie).

Interestingly, there is evidence that suggests that food texture can also play a role in weight gain. That is, a food that is harder to chew (and, ergo, digest) burns more calories during the digestion process than something softer and chewier. A Japanese study found that women who ate soft foods gained more weight than women who ate harder foods. Thus, look for my new book, The All Rock-Candy Diet, coming soon to a disreputable bookstore near you.

Oh, and ingredients can also make a difference:
the brownie is made from refined sugar and flour, making it easier for our bodies to extract the available calories than it would be from the complex carbohydrates of the oatmeal in the cereal bar.
Cooking also imparts more calories to foods, too. It never ends.

So, what are we to do? Cry, basically.

Well, no, but on the one hand, there is the suggestion that food labels—and the methodology used to derive nutritional info—be updated to reflect the latest science. After all, Atwater’s methods are more than 100 years old. We know a scosh more about chemistry and biology and nutrition these days. On the other hand, it would be costly to do so—and how much stock do consumers put in food labels anyway? And is the margin of error on the current labels such that anyone would change their behavior all that much anyway?

It’s been my experience over the past few years that worrying about 20 calories here and 30 calories there is less effective than just eating sensibly and using “common sense.” (That is, salad, vegetables--good; pizza, 90-ounce Porterhouse steaks--bad.) Portion control and, more importantly, exercise are far more valuable in terms of beating the battle of the bulge. Avoiding junk food also helps. In fact, my treadmill tells me how many calories I am burning (itself a guesstimate that is prone to error). While on line at the supermarket, if I see a candy bar or some other unnecessary snack item, I look at the guesstimate of its calorie count and can figure if it has 200 calories, it will take an additional 20 minutes of running to burn it off. Once you start measuring foods in terms of how much exercise it requires to negate them, random snacking starts to lose its appeal.

What also makes bad eating habits lose their appeal is the thought of outgrowing one’s clothes and having to buy new ones. Which brings me back to the “paradox of choice.” At what point did buying jeans become so complicated? They have Easy Fit, Loose Fit, Baggy Fit, Boot Fit, Relaxed Fit, Unrelaxed Fit, Downright Tense Fit, and something called “Standard Fit” which is the most unhelpful name for something since they invented “regular flavor gum.”

And this I find this even more nervewracking than grocery shopping.

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