The very act of eating less causes a stress response in the body that jacks up cortisol, a hormone that stimulates hunger and signals fat storage. A 2010 study published in Psychosomatic Medicine found that women who cut calories to lose weight experienced an increase in cortisol, even over another group who simply tracked their calories but didn’t reduce them. So how do you lose fat? Of course calories have to be reduced, but it’s how you perceive the cut that matters. Focus on eating better without restricting your overall consumption. Don’t starve!
Also, some foods require more effort to digest than others. It burns more calories to digest protein than it does carb foods.