Grapefruit has received exposure as one of the best weight loss fruits. The "Grapefruit Diet" claims that grapefruit is the ultimate fruit to eat if you want to drop pounds and inches. The American Council on Exercise recommends grapefruit for dieters to lose weight. Despite all the publicity, you might be curious how grapefruit actually affects your blood sugar and insulin levels, and how it stacks up in comparison to other fruits.
Glycemic Index
The glycemic index is a useful reference for diabetics and dieters who want to keep their blood sugar levels as stable as possible. When you eat a food that raises your blood sugar, your body releases insulin to "clean up" or lower your blood sugar. Insulin promotes fat storage, and you will want to prevent this as much as possible if you are trying to lose weight. The glycemic index ranks foods and beverages on how much they are likely to increase your blood sugar levels. Foods that have high rankings, especially those 70 and over, will increase your blood sugar very rapidly. Foods that have lower rankings, below 55 -- and particularly foods 25 and lower -- will not significantly affect your blood sugar and insulin levels.
Glycemic Index of Red Grapefruit
Red grapefruit has a very low glycemic index ranking of 25. This means that red grapefruit will not significantly increase your blood sugar and insulin levels. This ranking represents fresh red grapefruit without added sugars or syrups. Some red grapefruit is sold in convenient fruit cups, but is preserved in a high-sugar syrup that increases the glycemic index. Red grapefruit has a lower glycemic index ranking than almost any other fruit, according to Harvard Medical School. Apples, oranges, peaches, pears, bananas, watermelon and grapes all have a greater potential effect on your blood sugar.
Red Grapefruit Over White Grapefruit
Dr. Jonny Bowden, Ph.D. and clinical nutrition specialist, explains in his book "The 150 Healthiest Foods on Earth" that red grapefruit is more nutritious than white grapefruit. White grapefruit has more sugar, fewer cardiovascular benefits and fewer antioxidants than red grapefruit. A 2006 Israeli study published in the "Journal of Agricultural and Food Chemistry" reports that red grapefruit can lower blood triglyceride levels if they are high and lower LDL "bad" cholesterol. White grapefruit is not thought to have these heart-friendly effects.
Grapefruit Juice
Fresh grapefruit has a lower glycemic index than fresh grapefruit juice. Unsweetened 100 percent grapefruit juice has a glycemic index of 48, which is nearly double the glycemic index of a solid red grapefruit. Still, grapefruit juice is among low glycemic foods and beverages that rank below 55. Fruit juices tend to have higher glycemic index rankings than solid fruits because fruit juices do not have as high of a fiber content. If you are trying to control your blood sugar levels and you drink grapefruit juice, make sure it is 100 percent grapefruit juice. Beverages that are grapefruit "drinks" often have added sweeteners such as high-fructose corn syrup that can significantly raise your blood glucose levels and cause fat storage.
References
- "The 150 Healthiest Foods on Earth"; Dr. Jonny Bowden; 2007
- American Council on Exercise: Do Negative Calorie Foods Really Exist?
- Harvard Medical School: Glycemic index and glycemic load for 100+ foods
- Florida State University; Glycemic Index; Sanda Woodruff MS
- "Journal of Agricultural and Food Chemistry"; Red grapefruit positively influences serum triglyceride level in patients suffering from coronary atherosclerosis: studies in vitro and in humans; Gorinstein et al.; 2006
- Princeton University: A Sweet Problem (High Fructose Corn Syrup)
