What is the Grapefruit Diet? And Does it Really Work?

What is the Grapefruit Diet?

Much like any fad diet that promises rapid weight loss by consuming a certain food or combination of foods, the Grapefruit Diet is a meal plan you follow for 12 days and are “guaranteed” to lose 1 pound per day. But, what is the grapefruit diet REALLY?

The premise behind this is similar to most “diets” in that you are severely restricting your calories. This seems like a fairly obvious method for weight loss—regardless of what foods you eat (or don’t eat), in order to lose weight, a caloric deficit is necessary.

What is the Science Behind the Grapefruit Diet?

Yet there is some science to support eating more grapefruit. According to research led by Dr. Fujioka, principal researcher at the Nutrition and Metabolic Research Center at Scripps Clinic, “grapefruit can play a vital role in overall health and wellness and in battling America’s ever-growing obesity epidemic.”

Fujioka conducted a study in 2004 where 100 men and women participated in a 12-week “Grapefruit Diet” study. “On average, participants who ate half a grapefruit with each meal lost 3.6 pounds, while those who drank a serving of grapefruit juice three times a day lost 3.3 pounds. However, many patients in the study lost more than 10 pounds.”

There are many variations of this diet that have been circulating around for years; however, the one constant in each of these versions is the consumption of grapefruit before each meal. The reason for this is enzymes in the grapefruit may help reduce insulin levels and encourage weight loss. They are also believed to speed up the way our bodies burn fat and also may reduce appetite.

What is the Grapefruit Diet? Here’s the Daily Plan

The diet is very restrictive both in terms of choices and calories (and in my opinion, it also looks really boring!). According to diet.com, here’s the daily grapefruit diet plan:

  • Breakfast: 1/2 grapefruit + 2 slices of bacon + 2 boiled eggs + black coffee (no sugar) or unsweetened tea.
  • Lunch: 1/2 grapefruit + 1 cup of salad with low-calorie dressing + 8 ounces of lean chicken or water-packed tuna fish + black coffee (no sugar) or unsweetened tea.
  • Dinner: 1/2 grapefruit + as much salad with low-calorie dressing as desired + 8 ounces of lean chicken, lean beef, or fish + black coffee (no sugar) or unsweetened tea.
  • No snacks are allowed, and the only seasonings permitted for the meat or fish are herbs; no soy sauce, mustard, catsup, or other condiments are allowed.

The dieter is supposed to follow this diet for 12 days, then take two days off, and repeat the two-week cycle indefinitely.

I am not completely sold on the fact that you will lose 12 pounds in 12 days by consuming grapefruit before each meal, and I think it raises some concern that one would lose this much weight in such a short period of time.

With that being said, I do believe including grapefruit in your healthy diet is advantageous and has several benefits.

What are the Health Benefits of Grapefruit

  • Rich in vitamins C, A, K, D, and B complex, grapefruit also provides simple carbohydrates and is high in fiber and potassium, folic acid, calcium, phytonutrients, and phosphorus.
  • Grapefruits are rich in beta-carotene. This nutrient may be useful in supporting those with eating disorders and obesity issues.
  • When you cold press grapefruit rind, you are left with pink grapefruit oil, which may have a number of potential health benefits and uses. Some of the more commonly mentioned include as a hair treatment to make hair shiny while eliminating oily scalps. It may also help stimulate the lymphatic system, increase circulation, tone skin cells, support liver and gallbladder function, diminish appetite, even enhance self-esteem according to some sources, among others.
  • Grapefruits may also help boost your immune system, relieve sore throats, suppress coughs, help the body reduce fever, prevent constipation, support healthy blood pressure, cholesterol, and blood sugar levels, alleviate fatigue, relieve insomnia, and so on.

What is the Grapefruit Diet: A Recap

Again, if you severely restrict calories, you will lose weight temporarily—with or without following the Grapefruit Diet. Go ahead and enjoy your grapefruit for its tart flavor and health benefits. But when it comes to the Grapefruit Diet, I would prefer to see folks consume a healthy diet, including a wide variety of fresh fruits and vegetables, as opposed to relying on a proposed “miracle food.” You’ll likely enjoy it a lot more and therefore be more likely to stick to it long term, which is what’s most important for long-lasting success.


  • Is sugar in fruit bad for you?
  • Fujioka K, Greenway F, Sheard J, Ying Y. The effects of grapefruit on weight and insulin resistance: relationship to the metabolic syndrome. Journal of Medicinal Food. 2006 Mar 1;9(1):49-54.
  • Diet.com. Grapefruit Diet
  • Murase T, Misawa K, Haramizu S, Minegishi Y, Hase T. Nootkatone, a characteristic constituent of grapefruit, stimulates energy metabolism and prevents diet-induced obesity by activating AMPK. American Journal of Physiology-Endocrinology and Metabolism. 2010 May 25;299(2):E266-75.
  • The problems with plant based diets