Contrary to popular wisdom, the body can grow new fat cells. According to a new study in Proceedings of the National Academy of Sciences, when one packs on the pounds, fat cells in one’s lower body (hips and thighs) can multiply, while fat cells in the abdomen (belly fat) just seem to enlarge.

Lead researcher Michael Jensen and his team 'found that a gain of only 1.6 kg of lower-body fat resulted in the creation of 2.6 billion new adipocytes [fat cells] within 8 [weeks].' You read right: that’s 2.6 billion new fat cells in just two months.

After determining the body composition of their 28 normal weight participants, researchers at the Mayo Clinic had them feast on unhealthy treats like milk shakes, king-sized Snickers® bars, and high calorie energy bars for two months.

At the end of this period, the participants, whose average age was 29, had gained about 2 kg, equivalent to 4.4 pounds. The researchers looked at where the participants gained weight (i.e., upper or lower body) and sampled their fat to determine whether fat cells had multiplied or just expanded in size.

Lead researcher Michael Jensen and his team "found that a gain of only 1.6 kg of lower-body fat resulted in the creation of 2.6 billion new adipocytes [fat cells] within 8 [weeks]." You read right: that’s 2.6 billion new fat cells in just two months. In contrast, belly fat cells did not increase in number — only in size. Men and women both seemed to gain weight in their lower bodies, though it’s typically been thought that men gain in their bellies while women gain in their hips and thighs.

It’s not yet clear how the research will affect weight management or weight loss techniques. It does, however, show that longstanding beliefs about the way the body works can be overturned, as more and more research is beginning to demonstrate.