Eating red grapefruit affects your blood glucose levels because, like all varieties of fruit, it contains carbohydrate. Unlike protein or fat, carbohydrate is a type of nutrient that causes your blood glucose levels to rise. Eating red grapefruit will cause your blood sugar to rise.
Nutritional Information
Sugar, starch and fiber comprise the three main types of carbohydrate. Red grapefruit contains naturally-occurring sugar and fiber, but does not contain any starch. Sugar and starch carbohydrates raise your blood glucose levels, whereas fiber carbohydrate does not. One half of an average size red grapefruit contains 10.47 g of total carbohydrate -- 8.47 g from sugar and 2.0 g from fiber. Red grapefruit contains relatively few calories. One half of the fruit contains about 52 calories.
Blood Glucose
The naturally-occurring sugar carbohydrate in red grapefruit will cause your blood glucose levels to rise. Red grapefruit contains three types of sugar carbohydrate: sucrose, fructose and glucose. Glucose is the simplest form of sugar. After you consume a red grapefruit, the food material makes its way to your stomach in order to undergo digestion. The glucose molecules immediately pass through the lining of your stomach and get absorbed into your bloodstream. The sucrose and fructose molecules are quickly broken down into their simplest form, glucose, so that they too can go through the lining of your stomach and enter your bloodstream.
Fiber
Fiber is a unique carbohydrate in that it does not raise your blood glucose levels. Unlike unlike sugar and starch, fiber does not get broken down into glucose molecules. Instead, fiber passes through your body undigested. Red grapefruit is a particularly good source of soluble fiber. The soluble fiber in red grapefruit may actually help stabilize your blood glucose levels by helping to slow down your body's absorption of sugars into your bloodstream. Soluble fiber may help combat the effects of the fast-acting sugars in red grapefruit, which may help prevent sudden spikes in your blood glucose levels.
Intake Guidelines
Carbohydrates are an essential part of a healthy and balanced diet, as they are your body's primary source of energy. Based on a 2,000 calorie a day diet, most adults should generally consume between 225 g and 325 g of total carbohydrate daily. In general, fruit makes a healthy choice of carbohydrate because it is nutrient-dense and low in calories. Adult men and women should consume about 1 1/2 cups to 2 cups of fruit per day. An entire medium-size grapefruit is equivalent to 1 cup of fruit.
References
- American Diabetes Association: Food and Fitness -- Carbohydrates
- American Diabetes Association: Food and Fitness -- Glycemic Index and Diabetes
- United States Department of Agriculture Nutrient Database
- MayoClinic.com: Nutrition and Healthy Eating -- Glycemic Index Diet: Losing Weight with Blood Sugar Control, Nov. 24, 2009
- MayoClinic.com; Nutrition and Healthy Eating -- Dietary Fiber: Essential For A Healthy Diet; Nov. 17, 2009
- MayoClinic.com: Nutrition and Healthy Eating -- Healthy Diet: End the Guesswork with these Nutrition Guidelines, Feb. 22, 2011
