It is not easy, but researchers from the McMaster University, Canada, have shown that a protein rich but calorie deficit diet in combination with exercise is the way to go.
Published in the American Journal of Clinical Nutrition, the researchers wanted to prove the statement above. So they recruited 40 young men and split them into 2 groups: group 1 were given an energy restricted diet that was low in protein and group 2 were given an energy restricted diet high in protein. Both groups were subjected to a gruelling exercise regime 6 days a week.
After 6 weeks both groups lost some fat but the group fed the higher amount of protein lost more. Interesting, the group that had the lower protein diet managed to maintain their muscle which can decrease in an energy deficient diet without exercise. The group fed the higher amount of protein put on some muscle.
So to sum it up: a restricted calorie diet that is high in protein + exercise = increased muscle gain and fat loss.
Great findings, just a shame it was not published a month earlier when peoples motivation is at its highest.