What is the Grapefruit Diet?

Margo Upson

The grapefruit diet is a classic crash diet dating from at least the 1930s. It lasts for 12 days, and promises that dieters can loose up to ten pounds in that time. Anyone wishing to use the diet for longer than 12 days will need to take two days off between each session. It is a low-cost diet plan, and thought to be an influence for the popular low-carbohydrate Atkins diet.

People who are on the grapefruit diet should consume ample quantities of water.
People who are on the grapefruit diet should consume ample quantities of water.

The grapefruit diet is based on the idea that grapefruits contain a special enzyme that, when combined with protein, can rapidly burn fat, resulting in weight loss. It requires a very strict diet, with half of a grapefruit, or a glass of unsweetened grapefruit juice, consumed before each meal. Snacking and complex carbohydrates, such as pasta, baked goods and rice, are not allowed. Vegetables that are high in carbohydrates, including peas, yams, beans and corn, are also forbidden. The grapefruit diet also restricts what dieters can drink; black coffee and water are the only allowed beverages, besides a single glass of skim milk before bed.

The grapefruit diet relies on a supposed ability of a grapefruit enzyme to burn fat.
The grapefruit diet relies on a supposed ability of a grapefruit enzyme to burn fat.

There is no proof that the grapefruit diet really works; although there have been a couple studies done, no definite findings have ever been published proving that the weight loss is due to the grapefruit and not the calorie restrictions. Grapefruit is a very healthy fruit, with a lot of vitamin C, potassium and other nutrients. Pink grapefruit is a great source of beta carotene, which our body uses to produce vitamin A. With only 40 calories per fruit on average, it is a great fruit to eat as part of a sensible diet, but it does not seem to have any special weight loss powers.

Black coffee is allowed during the grapefruit diet.
Black coffee is allowed during the grapefruit diet.

The weight loss seen from the grapefruit diet is most likely a result of losing water weight and the severe calorie restrictions. Most versions of the diet restrict dieters to 800 calories, not enough to allow the body to perform normally. Fatigue, dizziness and loss of concentration are all possible consequences of consuming so few calories. This can also lead to a slower metabolism, slowing down the rate at which a body burns calories. As a result, as soon as the dieter begins eating normally again, all of the weight, and then some, will be regained.

The grapefruit diet may help a person lose weight for a short amount of time, but it is not a realistic weight loss plan for long-term use. The only guaranteed way to safely lose weight, and keep it off, is through making healthy nutrition choices and getting regular exercise. The grapefruit diet is not nutritionally sound and does not provide enough calories or nutrients to be safe for regular use.

The grapefruit diet might show short-lived results.
The grapefruit diet might show short-lived results.

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Discussion Comments


It might also be worth mentioning that grapefruit is usually banned when you are taking certain medications. That includes some contraceptive pills. I'm not sure how exactly, but grapefruit interferes with the ability of the pill to work, so if you eat it accidentally you are supposed to be aware that you aren't protected for a couple of days.

I just thought I'd mention it, because I always thought it was kind of strange and most people don't seem to know about it.

Maybe it is the same enzyme that makes you lose weight that interferes with the medication.

I really don't like grapefruit, so it doesn't matter how much weight I would lose, I just won't eat it.


I actually thought the grapefruit diet was just eating grapefruit for twelve days. Like the cabbage soup diet is basically just eating cabbage soup. 800 calories a day is ridiculous though. That's not even enough for a child. And the author of the article is right, the weight will come back on straight away. In fact, you will probably end up gaining even more weight in the long term, because you will have wrecked your metabolism.

Really, health is about good food, exercise and reducing stress. This diet has none of those things.

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