If someone already has poor metabolic health, long-term stress might make their body stop responding to a helpful hormone called FGF-21, which means their cells can't handle stress well and things just keep getting worse.

If you keep fasting or cutting calories for a long time without giving your body a break, your body might stop responding to a helpful hormone called FGF-21, and you won’t get as many health benefits from it anymore.

When the body stops responding to a hormone called FGF-21, it can't properly balance stress signals from the brain with how cells handle stress, leading to ongoing physical stress.

When you exercise or skip meals, your body makes a special protein called FGF-21 that helps it adapt and get healthier in response to the stress of those activities.

Your body makes a hormone called FGF-21 when under stress, and it helps control how sensitive you are to insulin and how much belly fat you store — but how and how long it’s turned on really matters.

Your body's FGF-21 hormone works best in short bursts, but too much exercise in people with poor metabolism might make the body stop responding to it quickly.