How Much Weight Can You Lose by Eating Grapefruit?

Most versions of the grapefruit diet cut calories, some to as low as 800 calories per day. This, alone, is the reason for temporary weight loss on the diet. Don't start such a low-calorie diet without consulting a doctor.

The Grapefruit Diet is a fad diet that can be traced back to the 1930s that involves eating a half a grapefruit before every meal. It is intended as a jump-start to a weight loss plan. The claims are that grapefruit contains fat-burning enzymes that will speed up metabolism and aid in quick weight loss.

A sample version of the diet involves:

• Breakfast:
  • 2 boiled eggs 
  • 2 slices of bacon
  • 1/2 grapefruit or 8 oz. 100 percent grapefruit juice without added sugar
• Lunch:
  • 1/2 grapefruit or 8 oz. 100 percent grapefruit juice without added sugar
  • Salad
• Dinner:
  • 1/2 grapefruit or 8 oz. 100 percent grapefruit juice without adding sugar
  • Salad or a red or green vegetable cooked in butter or spices
  • Meat or fish cooked in any manner
  • 1 cup coffee or tea 
• Bedtime Snack:
  • 8 oz cup of skim milk

Most versions of the diet cut calories, some to as low as 800 calories per day.

The diet may be difficult for vegetarians and vegans due to its reliance on meat and eggs for protein.

The Grapefruit Diet Plan claims dieters can lose up to 10 pounds in 12 days without hunger and while still eating meals at normal times.

A small study funded by the Florida Department of Citrus found that dieters who are a pre-meal snack of half a grapefruit, or drank a half-cup of 100 percent grapefruit juice or water before three main meals on a reduced calorie diet lost weight, lowered body mass index (BMI), and reduced waist circumference.

The study lasted 14 weeks and participants lost an average of 7.1% of their initial body weight, which averaged about 15 pounds per person. It should be noted that the group that drank water also saw these same reductions in weight, BMI, and waist circumference. 

The study did find some additional benefits in the grapefruit and 100 percent grapefruit juice groups, such as: 

• Increased HDL (“good”) cholesterol
• Decreased appetite
• Increased vitamin C intake 
• Increased fiber intake (for those who ate half a grapefruit)

Any diet that reduces calories dramatically is not healthy. Any weight loss that occurs is likely due to fluid loss and will be regained as soon as the dieter resumes normal eating. 

Grapefruit and grapefruit juice also interact with numerous medications, including:

• Statins
• Calcium-channel blockers
• Other cardiovascular drugs
• Immunosuppressants
• Sedatives
• Some neurological and psychiatric medications
• Phosphodiesterase inhibitors

While grapefruit is healthy, low in calories, and full of fiber and vitamin C, there is nothing to indicate it has special fat-burning capability or is any better for weight loss than other fruits and vegetables.