With its high fiber content and low glycemic load, citrus fruits may be a secret weight-loss weapon. Research suggests that dieter might be more successful if they select foods with staying power like whole citrus that help curb appetite and prevent overeating rather than employing some of the current fad diets. It has been shown that a person can actually eat
large quantities of food without consuming too many calories by choosing foods high in fiber and water content. Such foods include fruit, vegetables, whole grains, legumes and some soups. For example, oranges and grapefruit rank #1 and #2 in fiber out of the top 20 most-consumed fruits and vegetables. Studies provide evidence that they provide a greater feeling of fullness and keep blood sugar levels more constant resulting in better appetite control.
Current dieting studies suggest that dieters should focus on eating carbohydrates that have a low impact on blood sugar. This has led to the concept of Glycemic Load (GL), a ranking of food based on its carbohydrate content and its impact on blood sugar level. A GL below 10 is considered low. The GL for a medium-sized orange is 6 and that for a half grapefruit is 6. A listing of the GL values for many common foods can be found at the About Diabetes