A low-protein diet triggers mitochondrial uncoupling in fat cells. FGF21 levels rise, rewiring mitochondria to leak protons and generate heat instead of ATP. The result: your body burns more calories without eating more, even though the mitochondria work less efficiently.
Low protein diets increased levels of the proteins that are essential for turning the stored chemical energy in the bonds that are in our food, what many people call calories, into potential energy, this potential energy proton waterfall that mitochondria use to make energy. But funny enough, there was also a decrease in the outlet for this energy waterfall, the ATP synthase, So, simply, as simply as I can articulate this, all this suggests low-protein diets increased FGF21 levels, which changed the function of mitochondria in fat cells such that they generated energy less efficiently. This mitochondrial uncoupling— oops, there I go again with the jargon— explains why protein restriction, in this case 9% of calories from protein, increased energy expenditure so substantially.
