Blood Sugar & Watermelon

A young boy eating a large section of watermelon.
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Watermelon is a juicy and tasty treat during the summer months. It provides you with a wealth of nutrients, including potassium and vitamins A and C, and the fruit has little impact on your blood sugar levels, making it a smart snack or dessert. High blood sugar can lead to a host of medical problems, including diabetes and heart disease. Eat the right foods to prevent spikes in your blood sugar and decrease your risk of chronic disease.

High Glycemic Index

The glycemic index rates your blood sugar's response to different foods in relation to glucose, a simple sugar. Glucose is given a rank of 100, so the closer to 100 a food ranks, the more it should spike your blood sugar levels. When blood sugar levels rapidly increase, your pancreas secretes more insulin, which results in a quick drop in blood sugar. By eating foods low on the glycemic index, you should have a steadier increase in blood sugar levels. A 3/4-cup serving of watermelon has a glycemic index of 72, ranking it high on the glycemic index scale.

Low Glycemic Load

The glycemic index is a good guide to eating healthy, but you can't rely on it all the time. According to the Linus Pauling Institute, you need to also compare the level of carbohydrates eaten in a particular food to understand the impact on blood glucose and insulin response. The glycemic load of a food is determined by multiplying the glycemic index by the total carbohydrates in the food and dividing that number by 100. Watermelon has a glycemic load of 5. This fruit is low in carbohydrates and has a very small impact on blood sugar levels, explains Patrick Skerrett, executive editor of "Harvard Health."

Health Implications

By incorporating foods with low glycemic loads, such as watermelon, into your diet, you can improve blood sugar levels and reduce your risk of chronic disease. A study published in 2003 in "Diabetes Care" analyzed 356 diabetic patients and found those consuming low-glycemic-index foods improved their blood sugar levels. Chronically high blood sugar and insulin levels cause you to lose your ability to secrete insulin. This condition, known as insulin resistance, can lead to type-2 diabetes, according to the Linus Pauling Institute. A diet with high-glycemic-load foods also raises your triglyceride levels, or levels of fat in your blood, and reduces your good cholesterol, both of which put you at risk for heart disease.

Carbohydrate Counting

All fruits, including watermelon, contain carbohydrates. The American Diabetes Association encourages fruit consumption if you have diabetes but states you should count fruit as part of your meal plan. Speak with your physician, but on average you can eat 45 to 60 grams of carbohydrates at each meal. Fruit can be consumed in exchange for other carbohydrates, such as pastas, breads and dairy products. One cup of watermelon contains 12 grams of carbohydrates. Add a pop of color and nutrients to your dinner plate with a slice of watermelon, or enjoy it as a refreshing dessert during the summer months.