When fat tissue doesn't get enough oxygen in obese animals, it starts releasing inflammatory signals that may mess up the body's ability to use insulin properly.

When fat cells don’t get enough oxygen, they make less of a helpful hormone called adiponectin that helps the body respond to insulin, which might make insulin resistance worse.

In obese animals, fat cells with low oxygen may have fewer and less efficient power plants (mitochondria), making them worse at burning energy and possibly worsening insulin resistance.

In obese animals, the fat tissue grows too fast for blood vessels to keep up, so parts of the fat don’t get enough blood and oxygen, which may trigger problems like inflammation and insulin resistance.

In obese animals, fat cells that don’t get enough oxygen may die or stop storing fat properly, causing more fatty acids to leak into the blood, which can interfere with insulin function.

Even when obese mice lose weight by eating less on a high-fat diet, their belly fat stays inflamed — unlike mice that eat a healthy low-fat diet, whose inflammation goes away.