21 Day Grapefruit Diet

The grapefruit diet has been a common crash diet for decades. The 21-day plan calls for eating grapefruit at every meal, but a few other foods are allowed. Followers of the grapefruit diet believe the fruit has properties that hasten weight loss, but the rapid weight loss may instead be due to the very low caloric intake prescribed by the plan. Most grapefruit diet plans allow you to substitute grapefruit juice for the fruit.


A study by Dr. Ken Fujioka of the Scripps Clinic Division of Endocrinology found that test subjects who consumed grapefruit capsules, juice or fruit at every meal lost more weight than subjects who did not consume grapefruit. The study also found reduced insulin levels two hours after test subjects ingested grapefruit. Proponents of the ultra low-calorie grapefruit diet claim that the grapefruit and the combination of foods that must be consumed during the diet hasten weight loss. Grapefruit is an excellent source of vitamin C, according to the George Mateljan Foundation for The World's Healthiest Foods. The pink flesh is rich in the antioxidant lycopene, pectin that helps lower cholesterol, potassium and phytonutrients that assist in detoxification. Grapefruit may help ward off colon cancer and prevent kidney stones.


The 21-day grapefruit diet severely restricts calories and thus, nutrition. With a daily caloric intake of only about 800 calories, your body does not get enough fuel to allow for exercise during the diet. Following the diet for too long can cause health problems due to lack of proper nutrition. The diet lacks variety and can become monotonous, making it difficult to stick to the plan.


The grapefruit diet restricts starches and eliminates sugar. One cup of coffee or tea is allowed with dinner. Diet soda is not allowed. Grapefruit or grapefruit juice must be consumed at all meals. No other fruit is included in the diet. A bedtime snack consists of one 8 oz. glass of tomato juice or skim milk. In addition to the grapefruit, breakfast must consist of two boiled eggs and two slices of bacon. Lunch is a salad with any dressing you like, and any amount of meat cooked any way you want. Dinner is a salad and meat or fish. You may substitute a red or green vegetable cooked in butter for the salads. Some versions of the diet allow both cereal and pasta in small amounts.


The grapefruit diet recommends drinking eight to 10 glasses of water per day, which helps hydrate the body and can reduce hunger pangs. Grapefruit also has a high water content and is low in sodium, so it will not make you retain water weight. Alternating grapefruit with grapefruit juice can help alleviate boredom with this diet. While you may lose significant weight in a short time on the grapefruit diet, the weight is likely to creep back as soon as you finish the 21-day regimen. Some versions of the diet stipulate taking two days off midway through the diet.


Despite its beneficial properties as a fruit, little evidence exists that grapefruit has any magical power to significantly speed weight loss. Participants in the Scripps study lost, at most, a little over 3 lbs. over 12 weeks. According to Scripps Health of San Diego, grapefruit juice can increase the effects of some medications. Consult your physician and pharmacist before embarking on this diet.

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