The following Mark's Daily Apple article was written by Mark Sisson

and is narrated by Brock Armstrong.

Why is regaining weight so common?

It's an age-old story. A person has a huge amount of weight to lose and gets rid of most

of it through a combination of diet, exercise, and lifestyle modification. And they feel fantastic.

They've got energy for days. Their skin glows. They exude newfound confidence, and they experience other small

miracles. Many of you have lived this, but then something happens. The weight loss stops,

or worse, it reverses. They can keep the weight at bay as long as their diet is ironclad and they don't

skip any workouts, but as soon as they slip up even a little bit, they gain weight. And when they

gain, they seem to gain it faster and more easily than should be normal. It just doesn't

seem fair. What's going on here?

It comes down to how we gain and lose weight. See, there are two kinds of fat gain,

hypertrophic and hyperplastic. Adipose tissue hypertrophy is when existing fat cells get bigger.

Adipose tissue hyperplasia is when entirely new fat cells are created.

The vast majority of fat cells are created and established during childhood and adolescence. During infancy and from ages

9 to 13 appear to be especially crucial stages for adipus hyperplasia. After adolescence,

you're pretty much stuck with the number of fat cells your body is made. There are some

regional differences in how adults gain body fat,

with overfeeding creating new fat cells in the lower body fat, but not upper body fat,

but for the most part, the number of fat cells a person has is fixed during adolescence

and only increases in adults with obesity.

If your existing fat cells are filled to the brim and there's nowhere else to put the incoming energy, the body will make new ones.

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