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, does it work, and is it worth trying? Here's the breakdown.
What Is the Grapefruit Diet, Exactly?
The grapefruit diet involves eating grapefruit with every meal, usually for a period of about three weeks. Most versions of this weight-loss plan also limit your overall calories and food choices. The thinking is that grapefruit helps you burn more fat, and the goal is to lose weight quickly.
Dieters are allowed to have three or four daily meals, which may consist of grapefruit and high-protein foods, such as bacon, eggs, meat or skim milk. Some versions allow followers to consume coffee, salad and tomato juice. Other versions are even more flexible, allowing dieters to eat nonfat plain Greek yogurt, low-fat cheese, cottage cheese, fish, whole-wheat English muffins or strawberries.
There are also versions that restrict carbs and encourage eating high-fat foods. Others simply cap calories at 800 to 1,000 calories a day. The rules are not set in stone — it all comes down to which version of the diet you follow.
Can You Lose Weight on the Grapefruit Diet?
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. However, these claims lack any scientific evidence. Grapefruit and other citrus fruits don't burn belly fat, or any type of fat. If you do lose weight, it's likely for other reasons.
To date, there are no studies supporting the grapefruit diet or its effect on health or body weight. Also, no association has been found between grapefruit consumption and the risk of being obese or overweight.
Some studies suggest that grapefruit may facilitate weight loss, but 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.
For example, a small study published in the July 2012 edition of 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 modest weight loss. The differences between grapefruit consumers and non-consumers were negligible, though. And this was a study of just 74 participants, so its results cannot necessarily be assumed to apply to a larger population.
Grapefruit, however, is high in fiber — providing 2.5 grams per half, according to MyFoodData — and that could help with weight loss. According to a February 2015 review published in the Annals of Internal Medicine, eating more fiber can make weight loss easier, especially for those who find it difficult to follow traditional diets.
The USDA recommends adults get between 25 and 38 grams of fiber per day, but the average adult gets less than half of that, per Harvard Health Publishing.
Pros of the Grapefruit Diet
1. Grapefruit Is Low in Calories
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 stay hydrated.
2. It's High in Fiber
As mentioned above, grapefruit contains dietary fiber, which helps give you that full feeling and may help prevent overeating.
The fiber in grapefruit not only promotes satiety, it also keeps your digestive system running smoothly. 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 a position paper from the Academy of Nutrition and Dietetics.
3. Grapefruit Has Other Health Benefits
The fruit is chock-full of vitamins, minerals and antioxidants. Eating grapefruit has been linked with higher nutrient intakes, per a May 2014 review published in Food & Nutrition Research. Women 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 consume 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.
Grapefruit consumption 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 grapefruit.
Cons of the Grapefruit Diet
1. It's Overly Restrictive
Cutting out entire food groups and severely restricting calories are both sure signs of a fad diet and not a healthy plan for long-term weight loss. Fad diets provide only temporary results, according to the American Academy of Family Physicians, causing muscle and water loss, not fat loss. Most dieters gain back the lost weight (and sometimes even more) when they return to their usual eating patterns.
2. It Could Lead to Nutrient Deficiencies
Most versions of the grapefruit diet restrict calories well below what's considered safe. According to the 2015-2020 Dietary Guidelines for Americans, women shouldn't cut their calories below 1,200 a day, while men should stay above 1,500.
3. It Could Actually Sabotage Your Weight-Loss Efforts
Following an extremely low-calorie diet could negatively affect your metabolism. A November 2014 study published 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.
4. Grapefruit Isn't Safe for Everyone
Grapefruit and its juice interacts with quite a few medications, according to the FDA. This citrus fruit may interfere with statin drugs, corticosteroids, anti-anxiety meds, antihistamines, antihypertensives and others. If you're taking any of these drugs, consult your doctor before adding grapefruit to your diet.
So, Should You Try the Grapefruit Diet?
As with any fad diet, following the grapefruit diet could (and likely will) kickstart some weight loss, but it's not a diet that should be followed for an extended time period, nor should you try it if you're taking certain medications where grapefruit is contraindicated.
Instead, try simply adding grapefruit to your diet to reap the health benefits of this fiber-rich, low-calorie fruit. And check out our complete guide to finding the best weight-loss diet for you.
- Food & Nutrition Research: "Consumption of Grapefruit Is Associated With Higher Nutrient Intakes and Diet Quality Among Adults, and More Favorable Anthropometrics in Women, Nhanes 2003–2008"
- Metabolism Journal: "The Effects of Daily Consumption of Grapefruit on Body Weight, Lipids, and Blood Pressure in Healthy, Overweight Adults"
- USDA: "Grapefruit"
- Annals of Internal Medicine: "Single-Component Versus Multicomponent Dietary Goals for the Metabolic Syndrome: A Randomized Trial"
- American Academy of Family Physicians: "Nutrition for Weight Loss: What You Need to Know About Fad Diets"
- FDA.gov: "Grapefruit Juice and Some Drugs Don't Mix"
- Harvard Health Publishing: "Should I be eating more fiber?"
- Mayo Clinic: "C-reactive protein test"
- Journal of the Academy of Nutrition and Dietetics: "Position of the Academy of Nutrition and Dietetics: Health Implications of Dietary Fiber"
- 2015-2020 Dietary Guidelines for Americans
- American Journal of Clinical Nutrition: "Weight loss, weight maintenance, and adaptive thermogenesis"