Starving yourself is never a good way to lose weight. I can't believe people even ask this question. And no, if you only eat protein, then you body will burn protein for fuel, which means you will train you body to burn muscle as fuel. Eat a well balanced diet and have some patience.
in reply to tweeter, that starving is not good, and your body will adapt to burning protein and therefore muscles for energy
ive been told that it is far more effective to do cardio in the morning on an empty stomach, so the body uses its energy preserves(fat storage)
now, for example, if a person is 20% bodyfat, and wishes 2 lose weight(fat), then obviously the body is going 2 burn up the fat first, the main source of energy
sounds like your assuming a person already has low bodyfat, because if you keep your protein intake high, your muscles will have all they need 2 grow, so when it comes 2 cardio then, the main source of energy will come from the fat
thats why i asked about starving yourself or a strict protein diet, why would the body burn off protein, when the fat is a far more effective energy producer