Dieter's Dilemma: The Shocking Truth About Measuring Food in Grams and Calories

One of the great misconceptions about food is that it can be reliably reduced to measurements in terms of calories or grams of fat, carbohydrate, or protein. For instance, calories in food don’t match the calories in nutritional tables. I should be more specific: Calories in food don’t match calories in nutritional tables unless the food is high in sugar and highly processed.

There are similar problems with the standard measurements of carbohydrates, fat, and protein. Vitamin and mineral content are highly dependent on how a food is stored and can vary by factors of more than 99 percent, although the usual variation is 20 to 30 percent.

My conviction that calories are not countable is based on science, and it was reinforced by my experiences in Europe with the Europäische Institut für Lebensmittel- und Ernährungswissenschaft, the European Institute for Food and Nutrition Science. A locked metabolic ward in a hospital in Vienna in contact with the Institute found that its teenaged obesity patients simply did not lose weight. This was not because the patients purloined pizzas on their exercise outings or bribed their nurses for candy bars. It was because “identical” portions of the specially prepared metabolic diet had greatly varying calorie content.

Nutritional analyses of portions of a stew of the same weight (to the nearest hundredth of a gram) taken from the same pot, for example, yielded from 30.4 to 53.8 grams of protein. “Identical” samples contained from 10.4 to 20.1 grams of fat. They were measured as containing from 59.4 to 98.5 grams of carbohydrate, and from 588 to 809 calories.

Sometimes the patients were getting fewer calories than expected. Sometimes they were getting more. They received wildly varying amounts of carbohydrate, fat, and protein. For the organic, natural, and wholesome meals this nutritional hospital prepared, the nutritional tables proved to be useless. If nutritionists with PhDs suffer this kind of variation in their results, how can the rest of us be expected to count fat grams, carb grams, or calories with any degree of success?

The fact is, just as there are differences among people, there are differences among plants and animals of the same species. Even if you buy the same food every time, every purchase will have a different nutritional content. Individual plants and animals do not live out their lives so that their bodies can later conform to some nutritionist’s conception of what they should contain.

Let’s suppose for a moment that nutritional science overcame its measurement problems. Let’s suppose the information we find in countless nutritional tables was actually correct. Even if the laboratory measurements were right, there is considerable danger that interpretations, even using accepted statistical principles, could be wrong.

What is a minor nutritional fact some people—and nutritional science has tended to measure minor nutritional facts—is a major nutritional fact for others. A nutrient that is not especially important for a healthy individual may be very important for someone who is sick. Here’s another example.

One of the great debates of nutritional science during the 1970s (that's coming to the forefront again soon) was whether a meat-based diet or a plant-based diet was more conducive to good health. A plant-based diet, it was argued, placed a few people at risk of getting too much fat (because they were unusually sensitive to dietary fat) but it placed a lot of people at risk of getting too little protein. A meat-based diet, it was thought, placed only a few people at risk of getting too little protein (because their bodies had unusual problems absorbing protein) but placed a lot of people at risk of getting too much fat.

What the nutritionists overlooked, however, was that investigating single nutrients or single foods always involves tradeoffs. Even if the best possible diet is imposed on everybody “one size fits all,” many people might benefit, but some will always be hurt. Individual nutritional needs always trump general nutritional principles. Ethical and religious principles, of course, are a separate consideration.