According to research, the only way to combat the dreaded middle-age spread is to get physical. Many people start gaining a pound a year during midlife -- often because they have become less active as they age.
In addition, you start to lose muscle mass at age 40, and will continue to lose more each year unless you take steps to preserve it. This explains in part why many people today suffer from "sarcopenic obesity" -- they are overweight or obese and have suffered a progressive loss of muscle mass.
USA Today reports:
"There are people who don't gain weight, including athletes and people who maintain their physical activity level, eat a healthy diet with plenty of fruits and vegetables and lean protein."