Does the Sugar in Watermelon Make it a High-Carb Food?

If you watch your portions, the carbs in watermelon are balanced by nutrients

Plated wedges of summer farm fresh watermelon.
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Watermelons are moderately high in sugar, but small amounts can be part of a low-carb diet. It is best if you measure it carefully since a wedge of watermelon could be equal to several servings. The key is to keep the wedge to about 1-inch thick or eat no more than a cup of watermelon, which equals one serving and has 11 grams of net carbohydrates.

There are a number of nutrients in watermelon that have been found in studies to protect against heart disease and a myriad of other health issues.

Carbohydrate and Fiber Counts for Watermelon

Like the name suggests, watermelon is mainly composed of water. In one serving of watermelon, you will get about 5 ounces of water, which makes it a healthful alternative for getting your daily water needs met. Men and women need between 9 and 13 cups of water per day.

Preparation of WatermelonCarbs, Fiber, and Calorie Counts
1/2 cup diced watermelon5.5 grams net carbohydrates, scant amount of fiber, 23 calories
1 wedge (1/16 average watermelon, 10 ounces)22 grams net carbohydrates, 1 gram fiber, 86 calories

Glycemic Index and Glycemic Load for Watermelon

The glycemic index of a food is an indicator of how much and how fast a food raises your blood sugar. The International Tables of Glycemic Index and Glycemic Load: 2008 show the average glycemic index of watermelon as 76. 

The glycemic load of a food is related to the glycemic index but takes serving size into account.

A glycemic load of one is the equivalent of eating 1 gram of glucose. Watermelon looks much better by this measure, as there is little carbohydrate per serving.

Glycemic Load of Watermelon
1/2 cup of chopped watermelon: 1.5
1 wedge watermelon (1/16 average watermelon, 10 ounces):  6
1 serving (100 grams): 4

Health Benefits of Watermelons

Watermelon is a good source of vitamin C and vitamin A. It is also an excellent source of lycopene, a phytonutrient that studies show can be helpful in maintaining cardiovascular health and possibly bone health. Other phytonutrients in watermelon include flavonoids, carotenoids, and triterpenoids, which have anti-inflammatory and antioxidant benefits. A fully ripe red watermelon contains higher levels of these nutrients than less-ripe pink watermelon.

The amino acid citrulline is found in high concentrations in watermelon. It is marketed as a nutritional supplement for various purported benefits, but the amount in found in watermelon may not equal the concentration sold in capsule form.

The watermelon rind contains significant amounts of nutrients, including citrulline, and lower sugar content. Unfortunately, rind pickling in most cases is a recipe that calls for the addition of loads of sugar, which wouldn't be appropriate on a low-carb diet.

Watermelon Selection and Storage

A fruit that is considered "heavy for its size," means that the fruit has a higher chance of being a fresher, juicier watermelon. The outside should be firm and free of nicks or dents.

Look for the so-called "ground spot" where the melon was resting on the ground. In a melon that is fully ripe, this spot will be a creamy yellow color.

An uncut watermelon can be stored at room temperature, but it is better stored in a cooler place, ideally between 50 F and 60 F. After cutting, watermelon should be refrigerated.

    Low Carb Food Groups

    If a low-carb diet plan is what you are looking for, then leafy vegetables and nuts and seeds seem to be best bets. Most fruits, grains, legumes, and dairy products, tend to be higher in sugars or carbs. You can enjoy them as part of a balanced diet, but be sure to note their carb content and limit portions.

    A Word From Verywell

    While watermelon may look like it is high in carbohydrates, you can enjoy this fruit on a low-carb diet if you pay attention to portion sizes. It adds a colorful element to a green salad or fruit salad. A bit of natural sweetness may also please your palate, and you won't be wasting your carb allowance on something will less nutritional value.

    Sources:

    Atkinson FS, Foster-Powell K, Brand-Miller JC. International Tables of Glycemic Index and Glycemic Load Values: 2008. Diabetes Care. 2008;31(12):2281-2283. doi:10.2337/dc08-1239.

    USDA National Nutrient Database for Standard Reference, Release 28. USDA. https://ndb.nal.usda.gov/ndb/.

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