Raspberries and blackberries tie for the lowest-carb fruits at just 5 grams of net carbs per 100 grams. Strawberries come in close behind at 6 grams. But several other fruits, including some that might surprise you, also qualify as genuinely low-carb options. The full picture depends on whether you’re counting total carbs or net carbs (total carbs minus fiber), and how much you actually eat in a sitting.
The Lowest-Carb Fruits per 100 Grams
When you line fruits up by net carbs per 100 grams, berries dominate the top of the list. Raspberries deliver 10 grams of total carbs but pack 5 grams of fiber, leaving only 5 grams of net carbs. Blackberries are nearly identical: 11 grams total, 6 grams of fiber, 5 grams net. Strawberries have less fiber (2 grams) but start lower in total carbs (8 grams), landing at 6 grams net.
Star fruit is an underrated option. One medium star fruit contains just 6.1 grams of total carbs and 2.5 grams of fiber, putting its net carbs around 3.5 grams. It’s not always easy to find, but if your grocery store stocks it, it’s one of the lightest fruits you can eat.
Watermelon sits at about 7.5 grams of total carbs per 100 grams. That sounds low, and it is, mostly because watermelon is 92% water. The catch is that a typical wedge weighs nearly 300 grams, which means you’re actually consuming around 21 grams of total carbs if you eat the whole thing. Cantaloupe (about 8 grams per 100g) and honeydew (about 9 grams per 100g) behave similarly.
Practical Serving Sizes
Grams per 100g is useful for comparing fruits, but most people eat in cups and pieces, not weighed portions. Here’s how common low-carb fruits stack up in the servings you’d actually put on a plate:
- Watermelon: half cup diced, 5.5g carbs
- Casaba melon: half cup cubed, 5.5g carbs
- Strawberries: half cup sliced, 6.5g carbs
- Cantaloupe: half cup diced, 6.5g carbs
- Cranberries: half cup, 6.5g carbs
- Avocado: half cup, 6.5g carbs
- Blackberries: half cup, 7g carbs
- Plums: one medium, 7.5g carbs
- Raspberries: half cup, 7.5g carbs
- Honeydew: half cup diced, 8g carbs
All of these stay under 8 grams of total carbs in a reasonable serving. For comparison, a cup of sliced banana has 34 grams, a cup of mango pieces has about 25 grams, and a cup of grapes runs around 27 grams. The gap between low-carb and high-carb fruits is significant.
The Avocado Exception
Avocado is technically a fruit, and it’s a carb-counting outlier. A whole medium avocado has 13 grams of total carbs but 10 grams of fiber, leaving only 3 grams of net carbs. That’s lower than virtually any other fruit at equivalent weight. The tradeoff is 22 grams of fat and about 240 calories, most of it from heart-healthy monounsaturated fat. If you’re tracking net carbs specifically (as most keto plans do), avocado is arguably the single best fruit you can eat.
Lemons and Limes
These often get overlooked because people don’t eat them like snacking fruit, but they’re worth knowing about. A whole lemon has about 2.1 grams of sugar and 2.35 grams of fiber. A whole lime has 1.1 grams of sugar and 1.9 grams of fiber. Squeezed into water, dressings, or marinades, citrus adds almost no carbs to your day. If you’ve been avoiding lemon in your water out of carb anxiety, you can stop.
Why Berries Beat Other Fruits
Berries are low in carbs for two reasons. First, they carry a high ratio of fiber to sugar, especially raspberries and blackberries, where fiber accounts for nearly half the total carbs. Second, their small size and high water content mean you don’t consume much actual fruit mass in a typical serving. A half cup of raspberries weighs only about 60 grams, and 3 of those grams are carbs.
Berries also have a low glycemic index, meaning they raise blood sugar slowly and modestly. Cantaloupe, peaches, and plums all fall into the low-glycemic category as well (GI of 55 or below), which matters if blood sugar management is the reason you’re watching carbs in the first place.
Ripeness Changes the Carb Count
One detail that rarely gets mentioned: how ripe a fruit is meaningfully changes its sugar content. As fruit ripens, starches convert to sugars. Research measuring this shift found that total sugar content can more than double from ripe to overripe stages, climbing from about 7% to over 16% of the fruit’s weight. The glycemic index shifts too. Ripe fruits in one study had GI values ranging from 13 to 36, while very ripe versions of the same fruits jumped to 29 to 58.
This doesn’t mean you need to eat unripe fruit. But if you’re carefully managing carb intake, choosing fruit that’s just ripe rather than very soft and spotty will keep the sugar content closer to what nutrition labels report.
Fitting Fruit Into a Low-Carb Day
If you’re following a keto plan (typically 20 to 50 grams of net carbs per day), a half cup of berries or melon fits comfortably. Two servings a day is realistic for most people without blowing their carb budget, as long as the rest of the day stays on track. Avocado is essentially a free pass at 3 grams of net carbs per fruit.
If you’re on a more moderate low-carb plan (under 100 grams per day), nearly any fruit works in normal portions. The fruits worth being cautious about at that level are bananas, mangoes, grapes, and dried fruits like dates and raisins, all of which pack 25 to 35+ grams of carbs per cup. Sticking with berries, melons, peaches, and plums gives you the most fruit volume for the fewest carbs.