The Grapefruit Diet for Weight Loss: Does It Work?

Like one of those annoying pop-up ads that take over your entire phone screen, the grapefruit diet is a fad that just keeps coming back. It's been around since at least the 1930s, and each generation seems to embrace it at one point or another.

Several versions of the diet exist, but they all have one thing in common: followers restrict their calories and eat grapefruit at each meal, along with a limited variety of foods like bacon and eggs.

So, what is the grapefruit diet plan, does it work and is it worth trying? Here's the breakdown.

The grapefruit diet is a fad diet that originated in the 1930s and involves eating grapefruit with every meal, according to the Cleveland Clinic. The idea is that the fruit contains fat-burning enzymes that will help you lose weight quickly. There are different variations of the diet, but most last for a few days to three weeks (for instance, the 7-day grapefruit diet and 21-day grapefruit diet plan are two common programs).

Many versions of this weight-loss plan also limit your overall calories and food choices. For instance, the original grapefruit diet also emphasizes eating foods full of protein, fat and cholesterol (think: eggs, red meat and butter) while cutting carbs and sugar.

That said, the rules are not set in stone — it all comes down to which version of the diet you follow. For instance, you may have heard of the egg and grapefruit diet. It is what it sounds like: You eat grapefruit and high-protein foods like eggs with most meals, according to the Cleveland Clinic. Similarly, the grapefruit, bacon and egg diet emphasizes eating high-fat and high-protein foods like processed meat and eggs alongside your citrus.

The logistics of these diets can vary: For instance, you may encounter a 7-day egg and grapefruit diet plan or 3-day hard-boiled egg and grapefruit diet menus. But typically, grapefruit egg diet reviews claim that these programs can help you lose weight (more on whether that's accurate in a moment).

Here's a sample menu, according to the Cleveland Clinic, that will have you eating grapefruit every morning, noon and night:

• ‌Breakfast:‌ 1/2 grapefruit or 1 cup of 100% grapefruit juice with no added sugar, bacon and eggs, 1 cup of coffee or tea without cream or sugar
• ‌Lunch:‌ 1/2 grapefruit or 1 cup of 100% grapefruit juice with no added sugar, salad or vegetables cooked in butter and spices
• ‌Dinner:‌ 1/2 grapefruit or 1 cup of 100% grapefruit juice with no added sugar, meat or fish prepared any way

Proponents of the grapefruit diet say that grapefruit contains fat-burning enzymes and that you can lose up to 10 pounds in 12 days or so, according to the Cleveland Clinic. But is there really a link between grapefruit and weight loss?

Well, the scientific evidence to support this is scant and mixed. In an older March 2006 study in the ​‌Journal of Medicinal Food‌, 96 people with obesity were given either a placebo, a grapefruit capsule, apple juice, grapefruit juice or half a grapefruit before each meal for 12 weeks. At the end of the study, the fresh grapefruit group had significantly greater weight loss than the other groups.

However, a February 2011 study in ​‌Nutrition & Metabolism‌ could not replicate these results. After completing a two-week caloric restriction phase, 86 adults with obesity ate either fresh grapefruit, grapefruit juice or water before each meal for 12 weeks.

These pre-meal snacks were similar in weight, calories, water content and energy density, and everyone ate the same amount of food afterwards. All three groups lost weight, so the researchers concluded that while a preload before a meal successfully reduced caloric intake and weight, grapefruit had no special effects.

Another small July 2012 study in ‌Metabolism: Clinical and Experimental‌ assessed the effects of eating grapefruit on body weight, blood pressure and blood lipids. The people who ate grapefruit with each meal for six weeks lowered their blood pressure and cholesterol and shrunk their waist circumference, but only saw negligibly more weight loss than those who didn't eat grapefruit.

This was a study of just 74 participants, so its results cannot necessarily be assumed to apply to a larger population. And all of these studies are older, so new and bigger studies are needed to better establish a link (if any) between grapefruit and weight loss.

What's more, while some studies suggest that grapefruit may facilitate weight loss, none actually mention the grapefruit diet. Additionally, most research involving the fruit has been conducted on animals (so the results may not apply to humans) or has included only very small groups of people.

That said, grapefruit is typically a nutritious food to add to a balanced weight-loss diet that includes other fruits, vegetables, whole grains, lean proteins and beneficial fats. The citrus fruit is high in fiber (1.8 grams per half of a large fruit, according to MyFoodData), an essential nutrient that can help with digestive health and weight management, per the Mayo Clinic.

Indeed, eating more fiber can support weight loss, especially for those who find it difficult to follow traditional diets, according to a February 2015 review in the ‌Annals of Internal Medicine‌.

While following the classic grapefruit diet is typically too restrictive to be considered safe, there are some perks to adding the fruit to a balanced diet. Here's why:

With only 53 calories per serving (half a large grapefruit), according to MyFoodData, this citrus fruit fits into any diet. Plus, it's over 88 percent water, which helps to suppress appetite and keep you hydrated.

As mentioned above, grapefruit contains dietary fiber, which helps you feel full and thus makes you more likely to eat less, according to the Mayo Clinic.

The fiber in grapefruit not only promotes satiety, it also keeps your digestive system running smoothly, per the Mayo Clinic. Plus, unlike other carbs, it doesn't increase blood sugar levels.

That may be why higher fiber intakes are linked to a reduced risk of type 2 diabetes, heart disease, elevated cholesterol and colorectal cancer, according to November 2015 research in the ‌Journal of the Academy of Nutrition and Dietetics‌.

Eating grapefruit has been linked with higher nutrient intakes, as it's chock-full of vitamins, minerals and antioxidants, per a May 2014 review in ‌Food & Nutrition Research‌.

People AFAB who ate the fruit or drank its juice regularly had higher intakes of vitamin C, potassium, magnesium, fiber and beta-carotene compared to their counterparts who didn't eat grapefruit or its juice. Their triglyceride levels were also lower and HDL ("good") cholesterol levels were higher. Plus, the grapefruit group weighed less and had smaller waists.

Eating grapefruit has also been shown to lower C-reactive protein, a marker of inflammation, according to the ‌Food & Nutrition Research‌ review. These potential benefits could be due to the vitamins, minerals and phytochemicals in the fruit.

Trying the grapefruit diet comes with it's fair share of disadvantages, including:

Cutting out entire food groups and severely restricting calories are both sure signs of a fad diet, which is not a sustainable way to lose weight, according to the American Academy of Family Physicians.

The ambiguous and restrictive grapefruit diet is also hard to stick to, making it even more unsustainable for weight loss.

Fad diets, in general, aren't healthy, according to the Academy of Nutrition and Dietetics. Eating a well-balanced, calorie-sufficient diet including all the food groups ensures you get the nutrients your body needs for good health.

Most versions of the grapefruit diet restrict calories well below what's considered safe, which means you aren't getting the fuel you need to function at your best.

Following an extremely low-calorie diet could negatively affect your metabolism. In fact, a November 2014 study in the ‌American Journal of Clinical Nutrition‌ found that people still had slower resting metabolic rates a year after eating a very-low-calorie diet for eight weeks.

What's more, fad diets provide only temporary results, causing muscle and water loss, not fat loss, according to the American Academy of Family Physicians. As a result, most dieters gain back the lost weight (and sometimes even more) when they return to their usual eating patterns.

The lack of calories and nutrients can also leave you low on energy and too tired to exercise, which is the other key part of sustainable weight loss.

Grapefruit and its juice interact with quite a few medications, according to the FDA, including:

• Statin drugs for cholesterol
• Corticosteroids
• Anti-anxiety meds
• Antihistamines
• Blood pressure-lowering medication

If you're taking any of these drugs, talk to your doctor before adding grapefruit to your diet.

Many iterations of the grapefruit diet encourage eating foods that are high in saturated fats, including processed meats (like bacon and sausage) and butter, according to the Cleveland Clinic.

And while a plate of bacon and eggs is fine now and then, eating lots of bacon is not healthy for weight loss or overall wellbeing. That's because eating large amounts of these types of foods can drive up your cholesterol levels, which puts you at greater risk for heart disease, heart attack and stroke, per the Mayo Clinic.

Such a low-calorie diet with little nutrition beyond grapefruit and high-fat foods can also harm your bone health. Indeed, following a calorie-restricted diet has been linked to reduced bone mineral density, according to a June 2019 review in ‌Aging Clinical and Experimental Research‌.

Following a highly restrictive eating plan like the grapefruit diet can lead to dangerous yo-yo dieting or disordered eating, according to Oklahoma State University, which can increase your risk of developing an eating disorder.

As with any fad diet, following the grapefruit diet could kickstart some weight loss, but the weight you lose likely won't stay off. It's also not a diet that should be followed for an extended time period, nor should you try it if you're taking certain medications that can interact with grapefruit.

Instead, try adding grapefruit to a well-rounded diet to reap the health benefits of this fiber-rich, low-calorie fruit without dangerously restricting your calories and other nutrients.