How Many Calories in Grapefruit? Nutrition Facts & Macros

Half a grapefruit (123g) has approximately 52 calories. Per 100g, pink grapefruit has 42 calories. A whole grapefruit (246g) has about 103 calories. White grapefruit has fewer calories at 33 kcal per 100g. Very low-calorie for such a filling fruit.

Pink grapefruit has 31.2mg of vitamin C per 100g. Half a grapefruit (123g) provides about 38mg — roughly 42% of the daily recommended intake. While less than oranges (53mg per 100g), grapefruit is still a good vitamin C source with fewer calories.

Yes, pink and red grapefruit contain 1419 mcg of lycopene per 100g — the same antioxidant found in tomatoes. Lycopene gives pink grapefruit its color and is linked to heart health and cancer prevention. White grapefruit has virtually no lycopene. Half a pink grapefruit provides about 1745 mcg of lycopene.

Yes — this is important. Grapefruit contains furanocoumarins that block the CYP3A4 enzyme in your intestines, affecting how certain medications are metabolized. This can increase drug levels to potentially dangerous amounts. Affected medications include: some statins (atorvastatin, simvastatin), calcium channel blockers, some anti-anxiety drugs, and immunosuppressants. Always consult your doctor if you take medications regularly.

Pink grapefruit has 6.89g of sugar per 100g — relatively low for a fruit. Half a grapefruit (123g) has about 8.5g of sugar. This is less than oranges (9.35g per 100g), apples (10.39g), and grapes (16.25g). The bittersweet taste means less perceived sweetness despite moderate sugar content.

Grapefruit is excellent for weight loss at just 42 kcal per 100g. Half a grapefruit (52 kcal) is filling due to its water content (88%) and fiber (1.6g per 100g). Some studies suggest grapefruit may help with insulin sensitivity. The 'grapefruit diet' is extreme, but including grapefruit as part of a balanced diet is beneficial. Eat the whole fruit rather than juice for more fiber and fewer calories.