A reasonable suggestion is that an adult needs to increase activity and reduce food intake to create a deficit 500 to 1000 kcalories per day such a deficit produces a weight loss of to 2 pounds per week -a rate that supports the loss of fat efficiently while retaining lean tissue. In general, weight-loss diets provide about 1200 kcalories per day for women and 1600 kcalories per day for men.