It’s common to hear people say things like “I get fat no matter what I eat” or “I’m predisposed to obesity” or “I gain weight easily if I don’t exercise enough.” Are these claims true or false? And if two people consume the same number of calories, why do some people seem more prone to gaining weight than others?
Research has shown that overweight and obese individuals not only have more fat cells, but also have larger fat cells. Studies have confirmed that the number of fat cells is fixed in childhood and adolescence, and does not change in adulthood, even in cases of dramatic weight loss resulting from gastric bypass surgery. Instead, the volume of individual fat cells decreases by approximately one-third. This means that the number of fat cells in an adult remains constant, while the volume of each cell changes, causing weight to increase or decrease.
Another study found that adults replace 8% of their fat cells every year, regardless of body weight. This is not true, however, during menopause. In contrast, obese children add new fat cells at twice the rate of their peers, which is why obese children will ultimately have more fat cells when they become adults.
These findings explain why it is difficult for overweight and obese individuals to lose weight. They have accumulated a significant number of fat cells, which are constantly being replenished throughout adulthood, making it more difficult for them to lose weight. Studies have confirmed that excess fat cells can lead to a lack of leptin, a hormone that inhibits appetite and promotes metabolism. As a result of insufficient leptin, people eat more, and fat cells become swollen as they store excess fat.
Obesity is a well-known contributor to chronic health problems such as cancer, heart disease, and diabetes. Childhood is a crucial time for preventing obesity and related chronic diseases. Parents must establish healthy eating habits and weight control during childhood. In adulthood, the number of fat cells determines whether one is predisposed to gaining weight no matter what they eat.