Grapefruits help mainly in weight loss. Grapefruits contain certain chemical properties that help in controlling the insulin levels in your body - something that aids those dieting and those with diabetes.
There was a test conducted at Scripps Clinic of San Diego, US, where 100 obese people were divided into three groups: one group which ate half a grapefruit before each meal, one group which drank a glass of grapefruit juice before each meal, and one group which was instructed not to eat any grapefruit or drink any grapefruit juice. The tests showed that after three months of following their specific regimens, the group that ate half a grapefruit lost an average of 3.6 pounds; the group that drank a glass of grapefruit juice lost an average of 3.3 pounds and the average weight loss in the group that consumed no grapefruit in any form was just under 1 pound. In fact, some subjects lost even up to 10 pounds so it has been proved that despite affecting certain medications, grapefruit is extremely helpful in losing weight.