Watermelon is a poor fit for strict keto in a large bowl, but a small measured portion can fit if you have room in your carb allowance. Raw watermelon has 7.6g total carbs, 0.4g fiber and 7.2g net carbs per 100g, according to our watermelon carb guide using USDA watermelon data.
For portion planning, 1 cup diced (152g) has 10.9g net carbs in our carb guide. A smaller 50g portion has 3.6g net carbs, calculated as half the per-100g value. Weigh a small portion rather than treating a whole slice as a standard serving.
How to Cut Watermelon
Wash the watermelon before cutting it. On a stable cutting board, slice off the ends, stand it on a flat end and carefully cut away the rind. Cut the flesh into cubes or slices and weigh the portion you plan to eat. Remove seeds if you prefer, but that doesn’t remove the carbs in the flesh or turn a large serving into a keto-friendly one.
Other Keto-Friendly Fruits
If you want a larger fruit portion for fewer net carbs, compare berries or avocado with watermelon at the same weight. Watermelon can still fit in a small measured portion; it’s the amount that makes the difference.
Strawberries, blackberries and raspberries are options to consider, along with avocado. Check the serving size in our fruit carb guide before swapping one fruit for another.
Tomatoes can also add variety to a meal. Neither a fruit’s name nor its sweetness tells you how much you can eat within your carb allowance.
Keep all fruit portions within your daily carb allowance. For watermelon, use the weighed portion above rather than assuming it belongs in an unlimited keto fruit bowl.
Potential Risks of the Keto Diet
A restrictive eating plan needs enough variety to meet your nutritional needs. If you’re unsure whether keto suits your health needs, discuss it with a registered dietitian or healthcare professional. That decision is separate from whether a small portion of watermelon fits today’s carb allowance.