In most studies where low carb and low fat diets are compared, the low carb groups end up eating much more protein.
This is because people replace many low-protein foods (grains, sugars) with higher protein foods like meat, fish and eggs.
Numerous studies show that protein can reduce appetite, boost metabolism, and help increase muscle mass, which is metabolically active and burns calories around the clock.
Many nutrition experts believe that the high protein content of low-carb diets is the main reason for their effectiveness.
The Bottom Line is, low carb diets tend to be much higher in protein than low fat diets. Protein can reduce appetite, boost metabolism and help people hold on to muscle mass despite restricting calories.