We learned that a good dose of exercise in the morning could curb the appetite. 

For the study, published in Medicine & Science in Sports & Exercise, researchers measured the response of 35 women--17 of who were clinically obese and 18 who were of normal weight--to food images following a morning with exercise and a morning without exercise over two days. 

On the first day, each woman walked briskly on a treadmill for 45 minutes, then had their brain waves measured while looking at pictures of food within an hour after the workout.  The women repeated the process one week later, but did not exercise before viewing the images of food.  They were also asked to record the amount of food they ate on the days their brain waves were measured.

Researchers found that all of the women, regardless of weight, showed less motivation for food after they exercised than when they did not exercise.