Grapefruit may enhance weight loss

September 1, 2004 in Nutrition Topics in the News, Weight Management

Grapefruit may enhance weight loss
Eating half of a grapefruit three times per day before meals appears to help people shed unwanted pounds, according to new study findings from the Scripps Clinic in San Diego, California.

Regular grapefruit-eaters also experienced a decrease in insulin, which in excess can increase the risk of weight gain and cardiovascular problems.

The researchers explained that people have been espousing the \\"grapefruit diet\\" ever since the 1930s, and the concept has resurfaced from time to time over the years.

To investigate grapefruit\'s effect on weight loss, the team asked 100 obese people who were not trying to lose weight to eat grapefruit in various forms, and recorded how their weight changed over 12 weeks.

Three times per day before each meal, each group of patients either ate one-half of a grapefruit, drank a glass of grapefruit juice, took a pill containing grapefruit extracts, or drank apple juice. Participants were told not to vary their eating habits from before the study.

By the end of the study period, people who ate fresh grapefruit had lost 3-1/2 pounds without making any other changes to their diet.

Grapefruit juice and pills of grapefruit extract were less helpful in shedding pounds. However, both fresh grapefruit and the juice appeared to encourage weight loss in people with metabolic syndrome - which includes several disorders such as abdominal obesity, high blood pressure, elevated blood sugar and unhealthy cholesterol levels, and which sets the stage for type 2 diabetes, heart disease and stroke.

Previous research has shown that grapefruit does not ramp up metabolism, so these new results suggests that the fruit may encourage weight loss by lowering insulin levels.

Important Note: Grapefruit does interact with some medications!

Chemicals in grapefruit interfere with certain enzymes that break down certain drugs in your intestinal tract and liver. This can result in higher-than-desired blood levels of the drug and an increased risk of serious side effects.

The exact chemical or chemicals in grapefruit juice that cause this interaction aren\'t known. But these chemicals are present in the pulp and peel of grapefruit as well as in the juice. For this reason, any grapefruit product � including dietary supplements that contain grapefruit bioflavonoids � can interact with these medications.

Drugs that are known to have potentially serious interactions with grapefruit products include:

  • Antiseizure drugs such as carbamazepine (Carbatrol, Tegretol)
  • Antidepressants such as buspirone (BuSpar), clomipramine (Anafranil) and sertraline (Zoloft)
  • Benzodiazepines such as diazepam (Valium) and triazolam (Halcion)
  • Calcium channel blockers such as felodipine (Plendil), nifedipine (Adalat, Procardia, nimodipine (Nimotop), nisoldipine (Sular) and possibly verapamil (Isoptin, Verelan)
  • Human immunodeficiency virus (HIV) protease inhibitors such as saquinavir (Fortovase, Invirase) and indinavir (Crixivan)
  • HMG-CoA reductase inhibitors such as simvastatin (Zocor), lovastatin (Mevacor) and atorvastatin (Lipitor)
  • Immunosuppressant drugs such as cyclosporine (Neoral, Sandimmune), tacrolimus (Prograf) and sirolimus (Rapamune)
  • Antiarrhythmic drugs such as amiodarone (Cordarone)

Even waiting to take these medications up to 24 hours after you drink grapefruit juice doesn\'t prevent an interaction. The best advice is to avoid grapefruit products if you take any of these drugs, unless your doctor or pharmacist approves.

All research on this web site is the property of Leslie Beck Nutrition Consulting Inc. and is protected by copyright. Keep in mind that research on these matters continues daily and is subject to change. The information presented is not intended as a substitute for medical treatment. It is intended to provide ongoing support of your healthy lifestyle practices.