Save Calories; Order Your Steak Rare

Why Calorie Counts Are Wrong: Cooked Food Provides a Lot More Energy

...I was impressed to learn that raw-foodists are thin compared to those eating cooked diets, given that in most cases they are eating domesticated foods with lots of nutrients, are processing them in machines like electric blenders, and of course, living as most do in the developed world, never suffering through seasonal food shortage. Yet despite all these advantages over anyone who might try eating wild foods raw, the average woman on a 100% raw diet did not have a functioning menstrual cycle. About 50% of women entirely stopped menstruating! When a raw-foodist’s reproductive system does not allow her to have a baby even when her diet is composed of processed, high-quality, agricultural foods, the obvious explanation is that she is not getting enough calories.

So, how did people get along before cooking, if they couldn't reproduce effectively on a raw diet?

We suspect that there are two major reasons for cooked beef providing more calories than raw beef. In cooked beef, the muscle proteins, like the sugars in cooked starch, have opened up and allowed digestive enzymes to attack their amino acid chains. Cooking also does this for collagen, a protein that makes meat difficult to chew because it forms the connective tissue wrapped around muscle fibers. However, we do not know the exact mechanisms. What we do know, though, is that the mice had a spontaneous preference for eating cooked meat over raw meat, and their choice made sense, given that they fared better on it.

Mechanism aside, though, what the experiments indicated was some serious discrepancies in how calorie counts are measured. The USA uses the Atwater Convention for assessing calories in food, a century-old system that treats food as being composed of a certain number of components, each of which has a fixed calorie value–such as 4 kcals for a gram of protein, 4 kcals for a gram of sugars, 9 kcals for fats [ed: kcals are popularly called "calories"]. Modifications to the original convention allow advances in nutritional knowledge to be incorporated, such as better estimates for some specific types of carbohydrate. The system gives a good approximation for foods that are highly digestible and demand very little work by the digestive system, such as candy bars. It is convenient because it produces standardized numbers that everyone can agree on.

This is interesting because it points out what I've thought was true for a long time, that the calorie counts for  common foods are not accurate; they don't include the metabolic cost to digest and assimilate the food, and it turns out, that how foods are prepared and cooked has a strong effect on those costs.  Maybe the big advance in human culture came when we learned to cook food, and get a much greater return out of it.