Watermelon is the fruit with the least amount of calories among commonly eaten fruits, coming in at roughly 29 calories per 100 grams. That’s less than a third of what you’d get from the same weight of banana or grapes. But watermelon isn’t the only option if you’re looking for low-calorie fruit. Several others clock in under 45 calories per 100 grams, giving you plenty of variety.
The 10 Lowest-Calorie Fruits
Based on FDA nutritional data, here are the fruits with the fewest calories per 100 grams (about 3.5 ounces):
- Lemon: ~26 calories
- Watermelon: ~29 calories
- Lime: ~30 calories
- Starfruit: ~31 calories
- Strawberries: ~34 calories
- Cantaloupe: ~37 calories
- Honeydew melon: ~37 calories
- Grapefruit: ~39 calories
- Peach: ~41 calories
- Nectarine: ~43 calories
Lemons and limes technically win the calorie contest, but nobody sits down and eats a whole lemon as a snack. Among fruits you’d actually eat by the bowl or the slice, watermelon takes the top spot.
Why Melons Dominate the List
Three of the top seven spots belong to melons, and that’s no coincidence. Melons are mostly water, which adds weight and volume without adding calories. Watermelon is over 90% water by weight, which is why a generous one-cup serving contains just 46 calories. Cantaloupe comes in at 53 calories per cup, and honeydew at 60 calories per cup.
This makes melons especially useful if you want to feel full on fewer calories. A large wedge of watermelon (280 grams) is only 80 calories, roughly the same as a single small apple, but it’s a much bigger portion on your plate. That volume difference matters when you’re trying to eat lighter without feeling deprived.
Per-Piece Calories for Common Fruits
Calories per 100 grams is useful for comparing fruits side by side, but you probably eat fruit one piece at a time, not weighed on a scale. A whole medium peach (about 147 grams) has 60 calories. A medium nectarine (140 grams) also has about 60 calories. A cup of strawberries (147 grams) has 50 calories. A whole grapefruit half (154 grams) runs about 60 calories.
The practical takeaway: most of the fruits on this list fall between 50 and 80 calories in normal serving sizes. That’s remarkably low for a food that also delivers fiber, vitamins, and enough natural sweetness to satisfy a craving. Even pineapple, which tastes like one of the sweeter options, is only about 50 calories per 112-gram serving.
Starfruit: A Lesser-Known Option
Starfruit (also called carambola) doesn’t appear on most people’s grocery lists, but it deserves a mention. At 31 calories per 100 grams, it sits right between watermelon and strawberries. It also packs 2.8 grams of fiber per 100 grams, which is more than most melons offer. The flesh is over 91% water, crisp, and mildly tart. If you see it at the store and want something different, it’s one of the lightest fruits you can eat.
What About “Negative Calorie” Fruits?
You may have heard the claim that certain fruits or vegetables burn more calories during digestion than they contain, making them “negative calorie” foods. This isn’t supported by evidence. Your body does spend energy digesting food, a process called diet-induced thermogenesis, but that cost only amounts to about 5 to 15% of the calories in the food. So if you eat 30 calories worth of watermelon, you might burn 2 to 4 calories digesting it. You’re still netting 26 to 28 calories.
A study that directly tested this idea using celery (one of the most commonly cited “negative calorie” foods) confirmed that the body gains energy from it, not the other way around. The same principle applies to fruit. Low-calorie fruits are genuinely low in calories, but they’re not calorie-free, and your body doesn’t burn them off just by eating them.
A Note on Botanical Technicalities
If you want to get technical, some foods most people call vegetables are botanically fruits. Cucumbers are a good example. A whole 8-inch cucumber (301 grams) has just 45 calories, which works out to about 15 calories per 100 grams. That’s lower than any fruit on the list above. Tomatoes are similarly low. But since most people searching for low-calorie fruit are thinking about sweet fruit they’d eat as a snack or dessert, the ranking above sticks to those.
Choosing Low-Calorie Fruit That Keeps You Full
Calorie count alone doesn’t tell you how satisfying a fruit will be. Fiber and water content both play a role in how full you feel after eating. Strawberries and grapefruit pair relatively low calories with decent fiber, making them more filling bite for bite than something like watermelon, which is mostly water with less fiber. Starfruit, with its 2.8 grams of fiber per 100 grams, is another solid pick for staying satisfied.
Pairing fruit with a small amount of protein or fat (a handful of nuts, a spoonful of yogurt) slows digestion and extends that feeling of fullness. This is a more effective strategy than just hunting for the absolute lowest-calorie option. A peach with a few almonds will likely keep you going longer than watermelon alone, even though the peach has more calories per gram.
Ultimately, every fruit on this list is under 50 calories per 100 grams. At that level, the differences between them are small enough that taste and enjoyment should drive your choice. The best low-calorie fruit is the one you’ll actually eat consistently.