Both watermelon and pineapple are packed with nutrients that support overall health. However, fruit can be high in carbohydrates (a main source of energy in the body). This means that snacking on either watermelon or pineapple may affect your blood sugar levels.
First things first, fresh fruit can fit into a healthy, blood sugar-friendly diet, no matter if you have diabetes or not.
However, some fruits impact blood sugar more than others.
A 2025 study found that fresh watermelon had a GI of 50 and a GL of 5.6, while pineapple had a GI of 66 and a GL of 8.6. This means that both fruits have a low GL, which is considered to be a more accurate representation of how food impacts blood sugar.
The GL of pineapple is slightly higher than watermelon, meaning watermelon has less of an impact on blood sugar.
However, both fruits can be included in a balanced, blood sugar-friendly diet when eaten in moderation. Eating large servings of watermelon or pineapple will have a more significant impact on your blood sugar.
Here’s how a cup of watermelon and a cup of pineapple compare:
Nutrient
Watermelon (152 g)
Pineapple (165 g)
Calories
46
82.5
Total Carbs
11.5 g
21.6 g
Dietary Fiber
0.6 g
2.3 g
Total Sugars
9.4 g
16.3 g
Glycemic Index (GI)
50
66
Glycemic Load (GL)
5.6
8.6
Vitamin C
12.3 mg, or 13.7% of the Daily Value (DV)
79 mg, or 88% of the DV
Copper
0.06 mg, or 7% of the DV
0.18 mg, or 20% of the DV
Manganese
0.06 mg, or 2.6 % of the DV
1.53 mg, or 67% of the DV
Watermelon is lower in total carbs and sugar than pineapple, which is why it has a lower GL and less of an impact on blood sugar.
However, pineapple is higher in fiber and several vitamins and minerals, such as vitamin C, copper, and manganese. Vitamin C:
- Supports immune function
- Helps make collagen, a protein that keeps skin bouncy and healthy
- Helps with iron absorption
Pineapple and watermelon are also high in antioxidants, which prevent cell damage and lower inflammation. Eating foods rich in antioxidants can support overall health and protect against several health conditions, such as certain cancers.
While you can enjoy watermelon and pineapple while maintaining optimal blood sugar control, there are a few ways to make high-carb foods, like fruit, more blood sugar-friendly.
You can do this if you:
- Pair them with high-protein foods: Protein slows digestion, which can prevent post-meal blood sugar spikes and keep blood sugar levels stable throughout the day. Pair watermelon and pineapple with high-protein foods, like Greek yogurt and cottage cheese, for a blood sugar-friendly snack.
- Choose fresh or frozen fruit: For the best blood sugar control, choose fresh or frozen fruit and limit your intake of sweetened fruit products, such as canned fruit in syrup and sweetened dried fruit.
- Choose whole fruit over juice: Though 100% juice is nutritious, it’s much higher in carbs and lower in fiber than fresh fruit and will therefore have a greater impact on blood sugar.
- Consume fruit in moderation: While watermelon and pineapple have a low GL when consumed in normal portions, eating large amounts of these fruits will have a greater impact on blood sugar.
In addition to these tips, it’s important to follow a balanced diet high in blood sugar-regulating foods, such as protein, fiber, and other nutrients that support blood sugar control, including magnesium.
Instead of focusing on individual foods, look at your diet as a whole, including the amount of macronutrients (carbs, proteins, and fats) in your meals and your intake of foods known to regulate blood sugar.
Health.com uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
Ahmed J, Riaz M, Imtiaz R. Glycemic index and glycemic load values. Pak J Med Sci. 2021;37(4):1246-1247. doi:10.12669/pjms.37.4.4555
Singh MK, Han S, Ju S, et al. Fruit carbohydrates and their impact on the glycemic index: a study of key determinants. Foods. 2025;14(4):646. doi:10.3390/foods14040646
U.S. Department of Agriculture: FoodData central. Pineapple, raw, all varieties.
U.S. Department of Agriculture: FoodData central. Watermelon, raw.
National Institutes of Health Office of Dietary Supplements. Vitamin C: fact sheet for health professionals.
Du L, Sun G, Zhang X, et al. Comparisons and correlations of phenolic profiles and anti-oxidant activities of seventeen varieties of pineapple. Food Sci Biotechnol. 2016;25(2):445-451. doi:10.1007/s10068-016-0061-3
Manivannan A, Lee ES, Han K, Lee HE, Kim DS. Versatile nutraceutical potentials of watermelon—a modest fruit loaded with pharmaceutically valuable phytochemicals. Molecules. 2020;25(22):5258. doi:10.3390/molecules25225258
Yang J, Qian S, Na X, Zhao A. Association between dietary and supplemental antioxidants intake and lung cancer risk: evidence from a cancer screening trial. Antioxidants (Basel). 2023;12(2):338. doi:10.3390/antiox12020338
Shukla AP, Dickison M, Coughlin N, et al. The impact of food order on postprandial glycemic excursions in prediabetes. Diabetes Obes Metab. 2019;21(2):377-381. doi:10.1111/dom.13503
