Cooked food provides more energy than raw food

Craving meat but don't want the calories? Tuck into a plate of steak tartare. At least that's the implication of a new Harvard study which found that cooking meat provides more energy than raw meat.

Touted as the first of its kind, the results of the study could have big implications in the current food labeling system, which makes no distinction between the energy value of cooked and uncooked foods.

The study was published this week in the Proceedings of the National Academy of Sciences and reported in the Harvard Gazette.

To arrive at their conclusions, scientists from Harvard University fed two groups of mice either meat or sweet potatoes prepared in four ways: raw and whole, raw and pounded, cooked and whole, and cooked and pounded.

Over the course of 40 days, researchers tracked the changes in the body mass of the mice. The results showed that cooked foods delivered more energy to mice than their raw versions.

Preference tests also revealed that hungry mice strongly preferred cooked foods, the researchers said, suggesting that the subjects also had a strong biological impulse towards foods that offered more energetic benefits.

The findings expose serious shortcomings in the calorie-measurement tool used in modern food labels, the Atwater system, researchers said, as the current system fails to take into account the energy required to digest foods. Nor does it make a distinction between the food digested by the human, and food digested by the bacteria in the gastrointestinal tract. In both cases, processed, cooked meats provided more energy.

"This work illuminates that the tools we currently use to understand caloric intake, both in cases of malnutrition and cases of obesity, are suboptimal," said study co-author Rachel Carmody. "They've been based on the assumption that the human body is a perfectly efficient digestion machine, when, in fact, it's not ufffd but we now see that its efficiency is affected by food processing, particularly cooking."

Results of the study could also play an important role in two epidemics that plague the opposite ends of the world: obesity in the Western world, and malnutrition in the developing world, researchers said.

The research also lends further credibility to the raw food diet which advocates the consumption of plants in their natural state -- uncooked and unprocessed. The belief is that eating raw foods deliver the most nutritional benefits.