When fat cells get too big, they don't work well and the body tries to stop them from growing further to avoid damage and swelling.

In people with obesity, larger fat cells in the subcutaneous layer are more closely linked to insulin resistance in fat tissue than the presence of immune cells, aging cells, or inflammatory molecules, suggesting that fat cell enlargement, not inflammation, is the main factor disrupting fat breakdown.

Even small fat cells can be unhealthy and unable to grow when needed, which might cause problems too.

Scientists don’t know enough about how the whole mix of small and big fat cells works together to affect health.