When older male rats eat less food for several months, their bodies process sugar better and have healthier hormone levels.

When rats eat less food for several months, their testosterone levels go up compared to rats that eat normally.

Eating less food for six months helped older male rats have better sex lives by making them mount and mate faster and ejaculate more often, compared to rats that could eat as much as they wanted.

Older male rats that had eaten a fattening diet did better with blood sugar and gained less weight when they ate 30% fewer calories for five weeks — showing that cutting calories can still help, even after bad eating habits.

Researchers found that when they put middle-aged male rats on a diet with 15% or 35% fewer calories, it helped their reproductive health at first. But after a year on the diet, these benefits went away, and only one-third of the dieting rats still showed normal mating behavior compared to all of them at six months.