How many calories in
grapefruit?
Grapefruit runs 42 calories per 100g. Light enough that a generous portion barely moves the needle.
Common serving sizes.
Calories scale with portion. Here's how a typical grapefruit serving translates in your tracker:
What 42 calories means.
Very low calorie — at 42 kcal per 100g, grapefruit adds volume to a meal without meaningfully denting a calorie deficit.
Grapefruit vs. similar foods.
How grapefruit stacks up on calories and protein against foods people commonly compare it to:
Skip the lookup. Snap the plate.
Point your iPhone camera at grapefruit and Spotwell's AI estimates the portion and macros in a few seconds. Check it, adjust anything that looks off, and log it.
Download on theApp StoreQuick answers.
How many calories in grapefruit?
Grapefruit has approximately 42 calories per 100g. A typical serving — 3 oz (85g) — comes in at 36 calories.
How much protein is in grapefruit?
0.8g of protein per 100g. That puts grapefruit at roughly 1.9g of protein per 100 calories — a useful lens when comparing to other fruits sources.
How do I log grapefruit accurately?
The simplest method: weigh it on a kitchen scale, then enter grams in your tracker. With Spotwell, you can skip the scale — point the camera at the plate and the AI estimates the portion in a few seconds. Adjust the value if it looks off.
Is grapefruit good for weight loss?
It depends on your overall calorie target. Grapefruit is naturally low-calorie at 42 kcal per 100g, so it's easy to fit into a deficit.