Diet, grapefruit

Related Terms

Beta-carotene, diet, fad diets, fat-burning enzymes, grapefruit, vitamin C.
Note: For more information on grapefruit, please see Natural Standard's individual monograph on grapefruit.

Background

There are many versions of the grapefruit diet, which was developed in the 1970s. However, they all require the intake of one half of a grapefruit before every meal. Some versions require that dieters eat until they are full, but most diet plans limit daily caloric intake to less than 800 calories. The average dieter generally participates for one to three weeks.
The diet is based on the idea that grapefruits contain an enzyme that helps the body use fat for energy. Proponents of the diet claim that eating grapefruit before a meal will give the consumer the benefit of fat-burning enzymes.
The grapefruit diet breakfast typically consists of 1/2 of a grapefruit, two eggs prepared any way and two slices of bacon. Lunch generally consists of 1/2 of a grapefruit, a salad with any type of dressing and as much meat as desired. The typical dinner consists of 1/2 a grapefruit, a salad with any type of dressing or red or green vegetables prepared with butter and/or spices, meat or fish, and 1 cup of coffee or tea. Snacking in between meals is not permitted. However, one cup of skim milk can be consumed as a bedtime snack.
Grapefruit is low in calories, contains no fat and has minimal sodium. Grapefruit also contains an abundance of vitamin C and pink grapefruit contains beta-carotene. Anecdotal evidence suggests that the diet causes rapid weight loss.
Critics of the grapefruit diet argue that the amount of caffeinated beverages may be dangerous to some. The consumption of too many caffeinated beverages can lead to dehydration. The diet is also argued to be lacking in vitamins, minerals and other essential nutrients. Other critics argue that any diet that relies so heavily on one food is too restrictive.
The diet has been claimed to be dangerous because dieters are severely limiting caloric intake to less than 800 calories a day. Caution is also advised in those taking herbs, supplements or drugs as a constituent found in grapefruits, called furanocoumarins, may alter the safety and efficacy of these agents.

Author information

This information has been edited and peer-reviewed by contributors to the Natural Standard Research Collaboration (www.naturalstandard.com).

Bibliography

The Grapefruit Diet Plan. 11 May 2006.
The Grapefruit Diet. 11 May 2006.
Fujioka K, Greenway F, Sheard J, Ying Y. The effects of grapefruit on weight and insulin resistance: relationship to the metabolic syndrome. J Med Food. 2006 Spring; 9(1): 49-54.

Evidence

There is no specific evidence examining the effects of the specific grapefruit diet. However, there is research examining the effects of daily grapefruit consumption along with diet and exercise and a healthy diet. Patients assigned to the grapefruit group lost significantly more weight than the patients assigned to the placebo group.
Other studies suggest that grapefruit improves insulin resistance in patients with type 2 diabetes.