How Many Calories Are in a Grapefruit?

Whether ruby red, pink or white, grapefruits are healthy, filling citrus fruits packed with nutrients but low in calories. They can be cut in half and eaten section by section with a spoon, or peeled and eaten like an orange.

Calories

One half of a medium-sized grapefruit, the standard serving size, has 40 calories. A whole medium-sized grapefruit, therefore, has 80 calories.

Fat, Cholesterol and Sodium

Like most fruits, grapefruits contain no fat, cholesterol or sodium.

Carbohydrates

One half-grapefruit contains 10 grams of carbohydrates, 1 gram of which is dietary fiber and the other 9 grams of which are sugars.

Protein

A half a grapefruit contains just 1 gram of protein.

Vitamin C

Grapefruits are packed with vitamin C. A half of a grapefruit contains 70 percent of the recommended daily allowance for this vitamin.

Potential Drug Interactions

People taking certain cholesterol-lowering medications, calcium channel blockers and other types of drugs should not eat grapefruit or drink grapefruit juice, because of possible negative drug interactions. A physician or pharmacist can clarify whether it's okay to consume grapefruit while taking a particular medication.