The 100-Calorie Secret - Never Diet Again!

Normal weight individuals start with with about 40 billion fat cells, each fat cell has a life span of 10 years. New fat cells are produced by the body as old ones are removed at the rate of 10% per year. Normally, when energy needs equals  energy input,  there is a balance between new fat cells and old ones the body removes so that the total number remain the same.  As you overeat the fat cells fill up. Once the fat cells become  full they signal the body to make new ones. An obese person might have 100 billion fat cells-40 billion original ones, and 60 billion new ones.   These fat cells, mostly around our waist have a life of their own, enlarging and contracting depending up the amount of food and exercise we do. Enlarged fat cells secret numerous toxins
into the blood stream that cause may obesity related problems including heart attacks,
hypertension, diabetes and cancer.

Our body fat depends upon both the number of fat cells and the amount each cell stores. Since the actual number of fat cells never decreases its easy to fill up partially filled fat cells after when loss  when food intake exceeds energy output. This may help explain why its so easy to gain weight once you have lost it.