It is well-understood that being obese increases a person’s risk for depression and cognitive impairment.

Since the 1930s, many dieters have embraced the grapefruit fad diet; they are convinced that enzymes in the fruit actually break down body fat.

Although such claims have never been substantiated, a new study suggests that grapefruit juice may actually offer a way to control body weight.

Scientists at the University of California at Berkeley gave research mice grapefruit juice after they consumed a high-fat diet. The study showed that the grapefruit-drinking mice weighed about 20 percent less than another group of mice that drank sweetened water.

The animals also demonstrated better metabolic health (increased insulin sensitivity, decreased fasting blood sugars, better triglyceride profiles) than the sugar-drinking mice.

In addition, the scientists found that obese mice that drank grapefruit juice for 55 days had 8 percent less body weight.

Although it is not known how grapefruit juice helps control body weight, it may involve an ingredient that alters how the body produces and stores fat.

More research is needed to determine how this animal study transfers to humans, and it’s important to keep in mind that consuming grapefruits can affect drug metabolism, leading to higher drug levels and toxicity of medicines for heart arrhythmias, high blood pressure, high cholesterol, anxiety, and allergies.