"Crash diets (dramatically cutting down how much you eat) might help you to lose a few pounds at first, but they’re hard to sustain and won’t help you keep the weight off. It might seem like a quick and easy option, but eating too few calories can actually do more harm than good. If your calorie intake dips too low, your body could go into starvation mode. This will slow down your metabolism, making it harder for your body to lose weight. Make sensible, healthy changes to your lifestyle that you can stick to and avoid the fad diets."
This may explain why the fat-burning effects of eating more protein were confirmed in a study published in the American Journal of Physiology. One group was fed a high-protein diet (just over 1 gram per pound of body weight per day) while the second group consumed an amount closer to the lower recommendation of the RDA (recommended dietary allowance). The group eating the higher-protein diet burned the most fat.