Does Drinking Grapefruit Juice After Meals Help You Lose Weight?

Each year, over 50 million Americans go on a diet, but only 5 percent maintain their weight loss, according to Colorado State University. In the quest for quick and convenient weight loss solutions, consumers often choose between plans that require no dietary sacrifice or lifestyle change and programs with extreme dietary restrictions and rigid time-consuming workout plans. The former produces no lasting results and the latter usually is impossible to maintain. Grapefruit juice appears to be an alternative that promotes weight loss at a consistent, maintainable level independent of other dietary or lifestyle changes.

Scripps Clinic Study

A 12-week study conducted by Scripps Clinic in San Diego, California, observed the effects of consuming both grapefruit and grapefruit juice. One hundred men and women were segregated into two groups, and one group ate half a grapefruit with each meal while the other group drank one serving of grapefruit juice with their meals. At the end of 12 weeks, the subjects who ate grapefruit lost an average of 3.6 lbs. while the participants who drank grapefruit juice typically lost 3.3 lbs. While these are median numbers, it’s worth noting that some subjects lost more than 10 lbs. during the study.

Vanderbilt University Study

Researchers at Vanderbilt University conducted a 14-week study to determine the effectiveness of grapefruit, grapefruit juice and water as a pre-meal weight-loss solution in obese adults. Participants were put on a reduced calorie diet and instructed to consume half a grapefruit, half a cup of grapefruit juice or half a cup of water before their three main meals each day. Fourteen weeks later, each of the groups lost an average of 15 pounds. However, the groups consuming grapefruit or grapefruit juice experienced the additional health benefits of significantly escalating their HDL, or “good,” cholesterol levels while also increasing their vitamin C and fiber intake levels.

University of Western Ontario Study

The research team at the University of Western Ontario studied the results of a grapefruit flavonoid on laboratory mice. The mice were divided into two groups and given a steady diet of sugary and fatty foods, but, in the group fed the grapefruit molecule, fatty buildup was reduced by 80 percent, and cholesterol and triglyceride levels decreased. However, the researchers caution that this does not prove the effectiveness of grapefruit diets since humans would need to consume six to eight glasses of grapefruit juice a day to achieve comparable results.


Despite the research, opinions vary on the effectiveness of grapefruits as a weight-loss tool. Tufts University acknowledges the Scripps study but warns it was conducted with a small group of subjects and additional research is needed. The university recommends eating at least three fruit servings daily but suggests variety. Ace Fitness cautions against the grapefruit diet, lemon juice diet and other programs that focus on a single ingredient found in certain foods.