New research published in ScienceDaily in August 2026 shows that it is very difficult for people to keep weight off after losing it. Scientists found that the human brain remembers a person’s highest weight as normal and works to return to that weight.

This happens because, many years ago, humans needed to save body fat to survive when food was hard to find. The brain still tries to protect fat stores, even though we now have plenty of food around us.

Because of this, after losing weight, people feel more hunger and their bodies burn fewer calories. This makes it easy to regain weight. Understanding this helps doctors look for better ways to help people manage their weight, such as new medicines, instead of only relying on willpower.