Brain Rewards.

Restricting food intake increases the reward value of food, particularly high-calorie and appetizing food. The more successful people are at caloric-restriction dieting, the greater difficulty they will face in maintaining the restriction. Dieting by skipping meals and fasting is less successful than weight loss efforts characterized by intake of low energy, dense, healthy foods. If people want to lose excess weight, it would be more effective to consume healthy, low-fat/low-sugar foods during regular meals, rather than go for long periods of time without eating.

NeuroImage, May 2013