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Is There A Magical Ingredient In Grapefruits That Triggers Fat Burning? Kimberly Pinkney

 November 10, 2008


The 1930s may conjure up fond memories of movies such as All Quiet on the Western Front, fashion statements such as a-line skirts, or music such as Cole Porter’s Night and Day; however, for those who were in a war with their weight at the time, the 1980s probably also conjures up many fond memories of eating lots and lots of grapefruit! If you wanted to lose weight at the time, the most popular way to do it was the grapefruit diet.  In this day and age, if you mention the words a-line skirts, All Quiet on the Western Front, or Cole Porter, you are bound to get some strange looks.  However, there are still many people who are desperately trying to win their battle against obesity by eating whopping amounts of grapefruit!  How has a diet that emerged in 1930 stayed around so long?  Moreover, an even better question is: does the Grapefruit Diet work?


Also called the Hollywood Diet or the Mayo Diet, the Grapefruit Diet is one of the most popular of quick-fix, fad diets.  Thousands of dieters have signed up for the plan over the last seventy years or so ( with the promise that they would lose ten pounds during the twelve day period by simply adhering to the following menu:              


  1. Either 1/2 grapefruit OR 8 oz. juice (unsweetened)
  2. 2 eggs any style
  3. 2 slices of bacon


  1. Either 1/2 grapefruit OR 8 oz. juice (unsweetened)
  2. Salad with any dressing
  3. Meat any style and any amount.


  1. Either 1/2 grapefruit OR 8 oz. juice (unsweetened)
  2. Salad with any dressing OR a red or green vegetable cooked in butter or spices.
  3. Meat or even Fish any style cooked any way.
  4. Coffee or Tea (1 cup)

Bedtime Snack:

  1. 8oz. glass of tomato juice or 8 oz cup of skim milk.



The rules of the diet are simple: The grapefruit juice must be unsweetened.  Any food or beverage not on the diet is not allowed.  Snacking is only permitted after dinner.  Dieters can use all the butter and salad dressing they desire and prepare foods in any method desired, including frying.  Finally, dieters must drink sixty four ounces of water daily and eat all of the approved foods. 







The grapefruit diet is said to work because of a “magical” ingredient in grapefruits that when eaten with protein theoretically triggers fat burning and causes weight loss.( This “magical ingredient”, or key compound, supposedly prevents excess dietary fat and carbohydrates from being absorbed.  Therefore, incorporating grapefruit into your three meals each day reduces cholesterol levels and lowers your risk of heart disease.  There is no evidence for how the “mysterious” grapefruit enzyme works and why it is only in grapefruit and no other citrus fruits. 



It has been shown that the diet is effective in causing one to lose weight. However, the weight loss is primarily from fluids and not fat.  Therefore, generally the weight returns as soon as the dieter goes off the diet.  Simply put, the grapefruit diet is another low carbohydrate, moderately protein diet.  The average dieter will consume only 800-1000 calories per day. Because calories are being reduced to such a low level, most people still lose weight whether or not they consume grapefruit with each meal. Moreover, the low glycemic index, high fiber, and low calorie nature of the fruit may reduce insulin levels and help dieters feel full and eat fewer calories.  No studies substantiate grapefruit’s power to burn fat. 



The grapefruit diet can be very harmful.  Grapefruit is very acidic; consuming it in steady quantities can leave you with mouth sores and also irritate the stomach lining.  So, the Grapefruit Diet is not the ideal weight loss plan for anyone who suffers from ulcers or other stomach ailments. Grapefruit can also interfere with some medications because it prevents enzyme p-450 from breaking down medications in the intestinal tract. (



One small study published in 2006 and funded by the Florida Department of Citrus found that the addition of a half grapefruit or four ounces of juice with meals results in more than three pounds lost in a period of three weeks. ( Some participants reportedly lost ten pounds.  Researchers suspect that the addition of grapefruit to the otherwise healthy meal just reduced insulin levels and promoted weight loss.  Study participants also “slightly enhanced” their physical activity, which could also explain the weight loss. 





American Dietetic Association President, Connie Diekman says “There is no evidence that grapefruit has fat burning enzymes nor is it a magic bullet for weight loss. Sure you will lose weight, but it will be primarily fluids and not the fat associated with health risks.  And most people regain it as fast as they lose it.  So why bother?” ( Kelly Brownell, PhD director of the Rudd Center for food policy and obesity at Yale University says “There is no scientific basis to claim that grapefruit is special in this way.”  (



Over the years, many people have developed alternative versions to the Grapefruit Diet. However, one thing remains the same: a low amount of calories.  What should be remembered is that grapefruit can be part of a healthy eating plan because it's a healthy alternative not because it burns fat. Its fine to incorporate it into your daily diet, but do not take it to the extreme.







Works Cited




Callahan, Maureen. May 29, 2008.

Zelman, Kathleen.  February 08, 2007.

June 21, 2008.

Brownell, Kelly 2001.




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