5 doctors weighed in: Does alcohol thin the blood? 5 doctors weighed in Want a second opinion? Blood actually doesn't get thinned.  what we call blood thinners are agents that decrease the ability of the blood to clot, usually used in people whose blood clots excessively.
However, due to its very high water content, the same amount of watermelon that provides us with 16% of the DRI for vitamin C only costs us about 46 calories, or about 2% of our total daily calories on a 1800-2000 calorie diet.
Watermelon is a low-calorie food, containing only 46 calories per cup. According to the Mayo Clinic, it takes 3,500 calories to make a pound of body fat, so watermelon is not likely to contribute to weight gain. Because a cup of watermelon contains less than a gram of fat, it is also appropriate for a low-fat diet. Watermelon also contains 139 grams of water per cup along with a small amount of fiber, so it can help fill you up and make you less likely to eat other, higher-calorie foods included in the same meal.