The National Institutes of Health (NIH) have state of the art whole room calorimeters at $3m each. They are used to conduct fundamental metabolic research and provided some interesting insights into the role of metabolism in weight loss including: Heavier people generally have higher metabolic rates than skinny folks to meet the fuel demands of their larger bodies. Crash dieting can permanently slow a person’s metabolic rate Low carb diets don’t always improve fat utilisation There’s a...