torsdag 24 mars 2011

Richard Feinman, the Other

An interesting blog, and name :) Only an y differentiate from the other Feynman.
Feinman talks for low carbohydrate diet.

Dr. Feinman is Professor of Biochemistry at Downstate Medical Center (SUNY) in New York. Dr. Feinman’s original area of research was in protein chemistry and enzyme mechanism. His current interest is Nutrition and Metabolism, specifically in the area of diet composition and energy balance. His work in this area is stimulated by, and continues to influence, his teaching in the Medical School where he has been a pioneer in incorporating nutrition into the biochemistry curriculum.

Nonequilibrium thermodynamics and energy efficiency in weight loss diets


Thermodynamics of weight loss diets

It is commonly held that "a calorie is a calorie", i.e. that diets of equal caloric content will result in identical weight change independent of macronutrient composition, and appeal is frequently made to the laws of thermodynamics. We have previously shown that thermodynamics does not support such a view and that diets of different macronutrient content may be expected to induce different changes in body mass. Low carbohydrate diets in particular have claimed a "metabolic advantage" meaning more weight loss than in isocaloric diets of higher carbohydrate content. In this review, for pedagogic clarity, we reframe the theoretical discussion to directly link thermodynamic inefficiency to weight change. The problem in outline: Is metabolic advantage theoretically possible? If so, what biochemical mechanisms might plausibly explain it? Finally, what experimental evidence exists to determine whether it does or does not occur?


Reduced thermodynamic efficiency will result in increased weight loss. The laws of thermodynamics are silent on the existence of variable thermodynamic efficiency in metabolic processes. Therefore such variability is permitted and can be related to differences in weight lost. The existence of variable efficiency and metabolic advantage is therefore an empiric question rather than a theoretical one, confirmed by many experimental isocaloric studies, pending a properly performed meta-analysis. Mechanisms are as yet unknown, but plausible mechanisms at the metabolic level are proposed.


Variable thermodynamic efficiency due to dietary manipulation is permitted by physical laws, is supported by much experimental data, and may be reasonably explained by plausible mechanisms.

Complete here.
And collaborator - Department of Nuclear Medicine, Jacobi Medical Center.
OOPS? Something New?

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