What Is the Grapefruit Diet?

Grapefruit

Verywell / Alexandra Shytsman 

In This Article

The grapefruit diet has been around since the 1920s and 30s—and possibly earlier—and has since seen various iterations that tend to be extremely restrictive with promises of significant weight loss in short periods of time. It's true that grapefruit is a nutritious fruit, but 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 that became trendy among actresses. It eventually became known as the Hollywood Diet. The grapefruit diet saw another resurgence in the 70s, and over the years it also became associated (wrongly) with the Mayo Clinic. In 2004, the book, The Grapefruit Solution, suggested eating grapefruit to improve the success rate of the weight loss plan of your choice. 

How It Works

Although many versions 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 which cuts out many foods and calories.

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, consume prior to the rest of the meal.

Eggs and Bacon

Some forms of the 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, and it doesn't limit serving size.

Salad and Cooked Vegetables

Accompany your meat 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 these are excluded on the grapefruit diet, which makes it very restrictive.

Beverages

Drink plenty of water and a cup or two of tea or coffee per day.

Dairy Products

Some versions do allow for one 8 ounce glass of skim milk per day. Other than that, no dairy products are permitted in most other versions.

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 are consistent in calling for three meals a day and no snacks, as well as a fourth meal, or bedtime snack, usually a glass of skim milk or tomato juice.

Resources and Tips

If you do not care for 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—which is one of the actual benefits of a grapefruit diet.

Modifications

Remember: Consuming grapefruit, especially frequently or in large amounts, with certain medicines (more than 50 of them and counting) can have adverse health effects. If you’re on any medications, check with your doctor before adding grapefruit to your diet. Some of the more common meds on the avoid-grapefruit list include:

  • Thyroid drugs: In many people on thyroid hormone replacement therapy, consuming too much grapefruit can interfere with medications and make them less effective.
  • Statins (specifically Lipitor, Zocor, and Mevacor): Doctors prescribe these meds to people with high cholesterol. Grapefruit can interact with them and change the levels of medicine in the blood, as well as increase the likelihood of side effects.
  • Anti-depressants: Several of these medications, and others used to treat bipolar disorder and other mental health conditions, can also be affected by certain enzymes in grapefruit.

Pros and Cons

Pros

  • Grapefruit is nutritious

Cons

  • Very restrictive

  • Based on false assumptions

Pros

Beneficial Nutrients

Just adding grapefruit to your regular diet (without following the grapefruit diet) could offer some benefits, possibly even including weight loss. It is an excellent source of vitamins A and C and the antioxidant lycopene, as well as some flavonoids. It is low in calories and is lower in carbohydrates than some other fruits.

A full serving of grapefruit (154 grams) has about 2.5 grams of naturally occurring dietary fiber. It's a low-calorie snack and a filling one that will leave you less likely to keep on eating.

It's much pretty impossible to go overboard with grapefruit. Between the tart taste and the time it takes to peel them, you can't mindlessly munch your way through several hundred calories' worth like you might with other snacks.

A 2006 study showed that eating grapefruit could lower blood sugar and 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. A third showed no change in weight after a six-week dietary intervention (eating half a fresh grapefruit three times a day), although there were some decreases in blood pressure and cholesterol levels.

So grapefruit, on its own, may certainly have benefits. But a grapefruit diet is a different matter—and it's recommended that you consult with your doctor first.

Cons

Very Restrictive

As described, the diet is very low in calories and far too restrictive to be considered healthy for the long term, since it excludes almost all carbohydrates and many nutritious foods (such as whole grains and fruits other than grapefruit). Following it might also result in consuming too much saturated fat, as well, 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 help with weight loss because it takes the edge off your hunger and could curb the number of calories you consume. And despite the small studies that show some weight loss effects with grapefruit, overall 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, which means that you burn more calories chewing and digesting the fruit than you consume eating it. And when we burn more calories than we consume, we lose weight. Yes, grapefruit contains a reasonably small number of calories, but it’s not like celery in which you'd need to chomp your way through four 12-inch stalks before taking in 40 calories. Just half of a regular size grapefruit has around 52 calories. So unless you're doing jumping jacks while you peel, eat, and digest it, it's unlikely you're burning more than you're consuming!

How It Compares

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

USDA Recommendations

Food Groups

The Department of Agriculture dietary guidelines suggest consuming a balanced diet of fruits, vegetables, grains, proteins, and dairy products. Since it effectively eliminates several of these categories, the grapefruit diet doesn't meet this standard.

Calories

In most of its versions, the grapefruit diet typically 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. This tool can calculate a healthy calorie goal that's personalized for you.

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, with some suggesting building just one meal a day around an egg entree, others recommending consuming nothing but eggs and water, and another that 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. But 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 very specific list of foods to be consumed (such as 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 it does suggest eating some processed foods with very little nutritional value (hot dogs and crackers).
  • Effectiveness: Again, this diet could work simply by prompting users to cut back on calories, but health experts warn that the weight that's lost is mostly water and muscle mass. It is a version of intermittent fasting. But it also suggests eating high-calorie, high-fat foods such as ice cream and those aforementioned hot dogs.

M-Plan Diet

  • Food plan: Another type of "mono diet" like the grapefruit and egg diets, the M-Plan diet simply calls for replacing 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. Though 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 higher-calorie proteins for lower-calorie mushrooms. But a lot will depend on the choices they make at other meals.

A Word From Verywell

While the grapefruit diet commonly found online is not a good idea, eating more grapefruit might be, especially if you are trying to lose weight. It offers lots of nutrition in a low-calorie package. Additionally, you'll need to be cautious about eating too much grapefruit if you're on any of the medications that interact with it. In general, look for an eating plan that doesn't cut out major food groups, offers slow and steady weight loss, and is safe and healthy for you and your needs. Your doctor or a registered dietitian can help.

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