What Is the Grapefruit Diet?

Grapefruit diet

Verywell / Debbie Burkhoff 

The grapefruit diet has been around since the 1920s and 1930s (possibly earlier) and has seen various iterations. All of them tend to be extremely restrictive with promises of significant weight loss in short periods of time.

While it's true that grapefruit is a nutritious fruit, it does not necessarily have any magical powers to rev up weight loss.

What Experts Say

"While grapefruits are good for you, the health and fat-burning promises of the grapefruit diet are not evidence-based. The diet's small portions and limited food options are not sustainable, and grapefruit has a high risk of interacting with many medications and conditions."
Kelly Plowe, MS, RD

Background

The grapefruit diet is widely believed to be a byproduct of the Depression Era when it became trendy among actresses, eventually becoming known as The Hollywood Diet.

The grapefruit diet saw another resurgence in the 1970s. Over the years, it also became associated (incorrectly) with the Mayo Clinic. In 2004, a book titled "The Grapefruit Solution" suggested that eating grapefruit could improve the success rate of the weight loss plan of your choice. 

How It Works

While many versions of the diet exist, the basic premise of the grapefruit diet is to consume grapefruit prior to all three meals a day, for a duration of seven to 10 days or more. In addition, there is a restrictive eating plan for those three meals.

What to Eat

Compliant Foods
  • Grapefruit

  • Eggs

  • Bacon

  • Chicken or other meat

  • Salad or cooked vegetables

Non-Compliant Foods
  • Other fruits

  • All grains, starches, and sugars

  • Beverages other than coffee, tea, or water

  • Dairy products

Grapefruit

As the cornerstone of this diet, the serving size is half a grapefruit, or 8 ounces of grapefruit juice. You can also purchase powdered grapefruit in capsule form. For any of these choices, you consume the grapefruit prior to the rest of the meal.

Eggs and Bacon

Some forms of the grapefruit diet call for eating two eggs and two strips of bacon every day for breakfast (after the grapefruit).

Meat

Lunch and dinner on the grapefruit diet consist of a serving of meat along with salad. The diet makes no distinction between lean proteins and those with lots of saturated fat. It also doesn't limit serving size.

Salad and Cooked Vegetables

Your choice of meat is paired with a salad or some cooked veggies (some versions specify red or green vegetables only). In most cases, any kind of salad dressing is permitted.

Other Fruits

Some versions of the grapefruit diet allow for other fruit choices, while others do not.

Grains, Starches, and Sugars

All of grains, starches, and sugars are excluded on the grapefruit diet, which makes it very restrictive.

Beverages

You'll want to drink plenty of water. You can also have a cup or two of tea or coffee per day.

Dairy Products

Some versions of the grapefruit diet allow for one 8-ounce glass of skim milk per day. Other than that, no dairy products are permitted.

Recommended Timing

While there can be some variation in the grapefruit diet instructions, all call for eating the grapefruit (or drinking grapefruit juice) prior to meals. Most versions consistently call for three meals a day, no snacks, and a fourth meal (or bedtime snack)—usually a glass of skim milk or tomato juice.

Resources and Tips

If you do not like the taste of grapefruit, you can purchase capsules containing powdered grapefruit. However, you'll miss out some of the nutrition and all of the fiber you would otherwise get from eating the whole fruit (an actual benefit of the grapefruit diet).

Modifications

Before you try the grapefruit diet you need to know that it could possibly interact with medications you might be taking. Consuming grapefruit (especially frequently or in large amounts) with certain medicines can have adverse health effects.

If you are taking any medications, check with your doctor before adding grapefruit to your diet. More 50 medications are known to interact with grapefruit, but some of the most common medications that are not safe to mix with grapefruit or grapefruit juice include:

  • Thyroid medications. People on thyroid hormone replacement therapy need to avoid consuming too much grapefruit, which can make thyroid medications less effective.
  • Statins (specifically Lipitor, Zocor, and Mevacor). These medications are prescribed to treat high cholesterol. Grapefruit can change the levels of the medicine in the blood, as well as increase the likelihood of side effects.
  • Antidepressants. Several medications that are used to treat depression, bipolar disorder and other mental health conditions can be affected by certain enzymes in grapefruit.

Pros and Cons

Pros
  • Grapefruit is nutritious

Cons
  • Very restrictive

  • Based on false assumptions

Pros

Beneficial Nutrients

Adding grapefruit to your regular diet (even without following the grapefruit diet) can offer some benefits, possibly even weight loss. The fruit is an excellent source of vitamins A and C, as well as the antioxidant lycopene and some flavonoids.

Compared to other fruits, grapefruit is low-calorie and lower in carbohydrates. A full serving of grapefruit (154 grams) has about 2.5 grams of naturally occurring dietary fiber.

Grapefruit is a filling, but low-calorie, snack. Between the tart taste and the time it takes to peel them, you can't mindlessly munch your way through several hundred calories' worth of grapefruit the way you might with other snacks.

A 2006 study showed that eating grapefruit could lower blood sugar and, for some, lead to weight loss. Participants who ate half a grapefruit before meals for 12 weeks lost significantly more weight than a non-grapefruit-eating control group.

However, a third of the participants showed no change in weight after a six-week dietary intervention (eating half of a fresh grapefruit three times a day). Still, there were some decreases in blood pressure and cholesterol levels in this group.

Grapefruit can have some health benefits, but you should consult with your doctor before including it in your diet.

Cons

Very Restrictive

The grapefruit diet is very low in calories and far too restrictive to be considered healthy for the long term. It excludes almost all carbohydrates and many nutritious foods (such as whole grains and other fruits).

Following the diet might lead to consuming too much saturated fat, since it suggests eating meat twice a day without any recommendation to favor lean proteins.

False Assumptions

One common belief about grapefruit is that it contains a special enzyme that helps burn fat. This is not true. Eating any fruit before a meal could potentially help with weight loss because it reduces your hunger and could curb the number of calories you consume. 

Despite the small studies that show some weight loss effects with grapefruit, there is very little high-quality research (large, randomized studies in humans) that supports this claim.

Another argument for grapefruit is that it’s a "negative calorie" food—meaning that you burn more calories chewing and digesting it than it contains. When we burn more calories than we consume, we lose weight. Therefore, the argument is that eating a negative-calorie food would help with weight loss.

Grapefruit does contain a relatively small number of calories, but in terms of its "negative calorie" value, it's not like celery—which you'd need to chomp your way through four 12-inch stalks to consume just 40 calories.

Half of a regular size grapefruit has around 52 calories. Unless you're doing jumping jacks while you peel, eat, and digest it, it's unlikely that you would burn more calories than it contains.

How It Compares

The grapefruit diet shares many characteristics with other fad diets, though it contains a kernel of useful advice for people who are looking to lose weight.

USDA Recommendations

Food Groups

The U.S. Department of Agriculture's (USDA) dietary guidelines suggest consuming a balanced diet of fruits, vegetables, grains, proteins, and dairy products. The grapefruit diet eliminates several of these categories and therefore does not meet the USDA's standard.

Calories

In most of its versions, the grapefruit diet tops out at less than 1000 calories per day. That's far fewer than the amount recommended by the USDA, even for people who are trying to lose weight.

Similar Diets

Here's how the grapefruit diet stacks up against some other diets that claim to offer quick and easy weight loss.

Grapefruit Diet

  • Food plan: Consume fresh grapefruit or grapefruit juice prior to every meal. Eliminate all grains, starches, and sugars, including fruits other than grapefruit.
  • Duration: 10 days to two weeks, sometimes more.
  • Safety: This diet is too restrictive to be considered safe in the long term, and grapefruit can interfere with many commonly used medications.
  • Effectiveness: It's possible to lose weight on the grapefruit diet due to the severe calorie restriction. A better, more sustainable option would be to eat a healthy diet that includes grapefruit (if it is safe for you) as part of a sensible weight-loss plan. 

Egg Diet

  • Food plan: There are a few versions of the egg diet. Some suggest building just one meal a day around an egg entree. Others recommend consuming nothing but eggs and water. Another version pairs eggs with grapefruit.
  • Duration: Two weeks
  • Safety: The one-egg-meal-a-day plan could be safe provided the rest of the diet is nutritious and balanced. Other versions that restrict everything but eggs (and sometimes grapefruit) are not safe.
  • Effectiveness: As with other very restrictive diets, you could lose weight on an egg diet simply because you'll be consuming fewer calories. It's difficult to sustain this diet for the two-week period or to keep from regaining any weight you might have lost.

3-Day Military Diet

  • Food plan: Like the grapefruit diet, the military diet has a specific list of foods to be consumed (including tuna, saltine crackers, broccoli—and grapefruit), which are supposed to work together to boost weight loss.
  • Duration: Three days on, four days off, repeating as needed
  • Safety: At only three days, this diet is potentially harmless, but does suggest eating several processed foods that offer little nutritional value (for example, hot dogs and crackers).
  • Effectiveness: This diet could work simply by cutting calories, but health experts warn that the weight that's lost is mostly water and muscle mass. It is a version of intermittent fasting. The diet also suggests eating high-calorie, high-fat foods such as ice cream and hot dogs.

M-Plan Diet

  • Food plan: Another "mono diet" like the grapefruit and egg diets is the M-Plan diet. You replace one meal a day with a mushroom-based dish.
  • Duration: Two weeks
  • Safety: This diet is generally safe and healthy, depending on what's in the non-mushroom meals. Some experts have said that it's not an effective form of weight management.
  • Effectiveness: Mushrooms are nutritious and filling. This diet could help followers lose weight if they swap out high-calorie proteins for low-calorie mushrooms. The results will depend on the choices made at other meals.

A Word From Verywell

While the grapefruit diet commonly found online is not a healthy option, adding more grapefruit to your diet might be—especially if you are trying to lose weight. The fruit is a nutritious choice in a low-calorie package.

If you are taking medications, you will need to be aware of how much grapefruit you eat. Some medications that are used to treat thyroid conditions, high cholesterol, and depression can interact with grapefruit and cause adverse side effects.

In general, look for an eating plan that doesn't cut out major food groups, offers slow and steady weight loss, and addresses your health goals while also being safe. Your doctor or a registered dietitian can help you find a diet that is safe and effective.

Was this page helpful?
Article Sources
Verywell Fit uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. Scutts J. The Depression Era’s Magic Bullet For Weight Loss. The New Republic. Published May 27, 2016.

  2. Mugnolo C. What You Should Know About the Unofficial Mayo Clinic Grapefruit Diet. Livestrong.com. Updated September 17, 2019.

  3. Thomson TL. Ahrens JM. The Grapefruit Solution: Lower Your Cholesterol, Lose Weight and Achieve Optimal Health with Nature's Wonder Fruit. Carlsbad, California: LINX Corporation; 2004.

  4. Woman's World. The Grapefruit Diet Hack That Blasts Belly Bulge in Days. August 16, 2019

  5. Diet.com. Grapefruit diet.

  6. Picincu A. Livestrong.com. 21 Day Grapefruit Diet. Updated June 10, 2019.

  7. Beth Israel Lahey Health Winchester Hospital. Health Library - Grapefruit Diet. Updated June 16, 2017.

  8. Murphy MM, Barraj LM, Rampersaud GC. Consumption of grapefruit is associated with higher nutrient intakes and diet quality among adults, and more favorable anthropometrics in women, NHANES 2003-2008. Food Nutr Res. 2014;58. doi:10.3402/fnr.v58.22179

  9. Bailey DG, Dresser G, Arnold JM. Grapefruit-medication interactions: forbidden fruit or avoidable consequences?. CMAJ. 2013;185(4):309-16. doi:10.1503/cmaj.120951

  10. Colucci P, Yue CS, Ducharme M, Benvenga S. A Review of the Pharmacokinetics of Levothyroxine for the Treatment of Hypothyroidism. Eur Endocrinol. 2013;9(1):40-47. doi:10.17925/EE.2013.09.01.40

  11. Lee JW, Morris JK, Wald NJ. Grapefruit Juice and Statins. Am J Med. 2016;129(1):26-9. doi:10.1016/j.amjmed.2015.07.036

  12. El-Hage W, Samuel L, Vincent C, Catherine B. Mechanisms of antidepressant resistance. Front Pharmacol. 2013;4:146. doi:10.3389/fphar.2013.00146

  13. Murphy MM, Barraj LM, Rampersaud GC. Consumption of grapefruit is associated with higher nutrient intakes and diet quality among adults, and more favorable anthropometrics in women, NHANES 2003-2008. Food Nutr Res. 2014;58. doi:10.3402/fnr.v58.22179

  14. U.S. Department of Agriculture. Grapefruit, raw, pink and red, all areas. Updated April 1, 2019.

  15. Fujioka K, Greenway F, Sheard J, Ying Y. The effects of grapefruit on weight and insulin resistance: relationship to the metabolic syndrome. J Med Food. 2006;9(1):49-54. doi:10.1089/jmf.2006.9.49

  16. Abdul hakim BN, Yahya HM, Shahar S, Abdul manaf Z, Damanhuri H. Effect of Sequence of Fruit Intake in a Meal on Satiety. Int J Environ Res Public Health. 2019;16(22). doi:10.3390/ijerph16224464

  17. Onakpoya I, O'sullivan J, Heneghan C, Thompson M. The effect of grapefruits (Citrus paradisi) on body weight and cardiovascular risk factors: A systematic review and meta-analysis of randomized clinical trials. Crit Rev Food Sci Nutr. 2017;57(3):602-612. doi:10.1080/10408398.2014.901292

  18. Buddemeyer KM, Alexander AE, Secor SM. Negative calorie foods: An empirical examination of what is fact or fiction. bioRxiv. doi:10.1101/586958

  19. U.S. Department of Health and Human Services and U.S. Department of Agriculture. 2015–2020 Dietary Guidelines for Americans. 8th Edition. Published December 2015. 

  20. Foley KE. Quartz. A short history of terrible diets. September 1, 2018

  21. Bertoia ML, Mukamal KJ, Cahill LE, et al. Changes in Intake of Fruits and Vegetables and Weight Change in United States Men and Women Followed for Up to 24 Years: Analysis from Three Prospective Cohort Studies. PLoS Med. 2015;12(9):e1001878. doi:10.1371/journal.pmed.1001878

  22. Thompson C. Livestrong.com. What Is the Egg Diet, and Can It Help You Lose Weight?. Updated January 30, 2020.

  23. Academy of Nutrition and Dietetics. Staying Away from Fad Diets. March 18, 2019.

  24. Harvard Health Publishing. Calorie counting made easy.

  25. LaMotte S. CNN Health. Military diet: 3-day diet or dud?. March 8, 2018.

  26. Rettner R. HuffPost. M Plan, New Mushroom Diet Promising Selective Weight Loss, Won’t Work, Experts Say. September 9, 2013.