At what age does your body start increasing the size of existing fat cells?

During infancy and adolescence, adipose tissue is growing by a combination of the increase in fat cell size (to a lesser extent) and (above all) the number of these cells. In adults, fat cell number is constant over time in spite of a large turnover (about 10% of the fat cells per year) when body weight is stable.

one day because their over eating or whenever it kicks in their body

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