When you lose weight, do you lose fat cells?

Q: When you gain weight, are you growing more fat cells? When you lose weight, do you lose fat cells?

A: We?re still learning about how fat cells, or adipocytes, function with regard to weight changes.

The current thinking holds that weight gain may increase the number of fat cells as well as their size. As to weight loss, it was long thought that once you added fat cells, you could only reduce their size, not their number. Some experts stand by that theory. But others contend that the adipocyte count can be reduced in certain circumstances, such as when people lose a lot of weight and keep it off for a long time.

While theories about fat cells remain controversial, the research into ?weight cycling? has really solidified. If you?re trying to lose weight, understanding the disadvantages of weight cycling (or yo-yo dieting) may come in more handy than worrying about quantities of adipocytes.

For the most part, humans didn?t have the option of overeating until relatively modern times. The human body evolved accordingly, with adaptations designed to improve survival chances in times of famine. So when the body perceives that food is in short supply, it responds by trying to protect fat supplies from depletion.

This may influence what happens when you go on one strict diet after another, even if you successfully lose some weight initially. After that early weight loss and a string of diets, it becomes more and more difficult to lose weight. It may be that the body, in its own way, is trying to keep you from starving to death.

Study upon study shows that most people who diet eventually gain back what they lost. Some gain back more. The next time they diet, those excess pounds stick to the hips more stubbornly. Pretty soon the weight cycling has become an upward spiral.

Now, don?t take this to mean you should just surrender yourself to obesity. Quite the contrary — obesity can have profound negative health effects. Look for a weight management program that?s free of extremes and doesn?t make you feel hungry or deprived.

A winning strategy will be something that you feel comfortable with on a lifelong basis. Plan to make changes in your eating and exercise habits very gradually, not abruptly or all at once. It should be a modest approach that includes a variety of foods and incremental changes.