Effect of Dietary Protein Content on Weight Gain, Energy Expenditure, Body Compositio

[Manic]

First seen BrinkZone, the original study can be found on JAMA : Effect of Dietary Protein Content on Weight Gain, Energy Expenditure, and Body Composition During Overeating.

In summary, weight gain when eating a low protein diet (5% of energy from protein) was blunted compared with weight gain when eating a normal protein diet (15% of energy from protein) with the same number of extra calories. Calories alone, however, contributed to the increase in body fat. In contrast, protein contributed to the changes in energy expenditure and lean body mass, but not to the increase in body fat.

 

[Totentanz]

There are studies showing that eating higher levels of protein causes greater fat loss and less lean mass loss during a diet. I think those diets and this one linked above don't really apply to people like us. The 25% of calories from protein group is a little closer. Seriously, when it the last time you got only 15% of your calories from protein? All this study shows that you definitely need protein for muscle growth. The low protein diet gained no lean mass, whereas the mid and high protein groups gained significant amounts of lean mass just from increased protein alone.

Conclusions: Among persons living in a controlled setting, calories alone account for the increase in fat; protein affected energy expenditure and storage of lean body mass, but not body fat storage.