Is watermelon fattening or good for weight loss?

I have to admit that watermelon is one of my favourite fruits, largely due to its extremely sweet and refreshing taste. I particularly enjoy drinking watermelon smoothies, either on their own or with other ingredients added.

Watermelons have a lot of health benefits such as helping to lower blood pressure, soothing sore muscles, fighting off cancer and promoting beautiful skin.

That being said, it is a fruit that does have a fairly high sugar content, leaving many people wondering whether it could cause weight gain.

Is watermelon fattening?

How do people gain weight and become fat? The simple answer is that they consume more calories than they burn; doing this over a lengthy period of time leads to weight gain.

A calorie is a unit of energy and calories are obtained from the food that you eat. Everybody is unique and so people require different amounts of calories. You can use the calculator here (included below) to determine how many calories you need in order to maintain your current weight and also how many you need to lose weight.

Gender Age Weight Switch to lbs Height Switch to feet and inches Activity Level

This calculator will never show a number below 1000 calories per day. Please speak to a qualified health professional before attempting to eat less than that.

For example, if you are a 30 year old woman who weighs 65 kgs (132 lbs), are 160 cm tall (5 feet, 3 inches) and exercise 3 – 5 days a week, you will need to eat 2075 calories on a daily basis in order to maintain your current weight and around 1660 calories to start losing weight.

If you were to consume say 2800 calories everyday for a lengthy period of time, you would begin to start gaining weight; this is simply because you would have a surplus of 725 calories. The excess calories that you eat are converted into fat and this fat is stored throughout your body.


So, is watermelon fattening? Well, it depends on how much you eat.

Lets take a look at the nutritional values of 1 cup of watermelon and compare that to a whole watermelon:

1 cup (around 152 g)

Calories 46
Fat 0.2g
Cholesterol 0
Sodium 2mg
Carbohydrates 11g
Fiber 0.6g
Sugar 9g
Protein 0.9g

As you can see from the table, 1 cup of watermelon is extremely low in calories. The main reason for this is that watermelon is made up of 92% water and water contains 0 calories. So the main source of calories is the carbohydrate (the sugar to be specific) in the watermelon.

1 watermelon (around 4500 g)

Calories 1371
Fat 7g
Cholesterol 0
Sodium 45mg
Carbohydrates 341g
Fiber 18g
Sugar 280g
Protein 28g

1 watermelon contains around 1371 calories. You will quickly notice the huge difference compared to 1 cup of watermelon.

So the lesson here is portion size. Any food if eaten in abundance can cause weight gain, simply because the number of calories you eat shoots up. Eating 1 – 3 cups of watermelon everyday is not going to make you fat. Eating a whole watermelon on the other hand (which by the way 99% of people will be unable to do) most likely will, because your daily calorie consumption will most probably be much more than what your body needs.

What about the sugar content?


Due to their sweet taste, many people assume that watermelons are loaded with excess sugar. Yes, they do have a fairly high sugar content but there are other fruits that contain more. Using our healthy food finder tool, you will notice that when compared weight for weight, grapes, mangoes, bananas, apples, blueberries, pineapples, oranges and even grapefruit & papaya contain more sugar than watermelon.

When you eat carbohydrate rich foods, your blood sugar levels rise. In response to this, your body releases a hormone called insulin which instructs cells in your body to absorb glucose from the blood stream. Any glucose in your blood which is not used by these cells is stored in your liver and muscles as glycogen. However, the body can only store around 2000 calories worth of glycogen; any excess glucose that is not stored as glycogen is stored as fat.

The glycemic index (GI) of a food gives you an indication of how quickly and by what amount a given food will raise your blood sugar. The higher the glycemic index, the higher your blood sugar will be raised. Pure glucose has a glycemic index of 100; watermelon has a glycemix index of 72 which is considered to be quite high.

However, a better way of measuring a foods impact on blood sugar is to do so by measuring the glycemic load (GL). This takes into consideration the carbohydrate content of a given food. Watermelon has a GI of 72 but since it is made up of 92% water, it only contains 5 – 6% of available carbohydrate.

To calculate the GL of a food, you multiply the GI by the amount of carbohydrate available in 1 g of the food. So in this case it would be 72 x 0.06 = 4 (rounded down). A GL of less than 10 is considered to be low, 11 – 19 to be medium and greater than 20 to be high. A white frozen bagel has the same GI (72) as watermelon however it has a much higher carbohydrate content and so its GL is significantly higher at 25.

That being said, as mentioned above, portion size does matter. If you eat 2 cups of watermelon you’re going to ingest around 18 g of sugar, which is nothing to worry about (always speak to a doctor if you are diabetic). On the other hand if you eat a whole watermelon, you will ingest 280 g of sugar, which is way to much. If you are an otherwise healthy individual, you should try to keep your sugar intake from fruit between 25 and 40 g per day. Read this article to learn how much daily sugar consumption is considered healthy.

How watermelon can help you lose weight


Now we know that watermelon cannot lead to weight gain (so long as it is eaten in reasonable quantities), lets look at some of the benefits it has for weight loss.

It is low in calories

After reading the section above, you know that in order to lose weight, you need to be in a calorie deficit. The easiest way to achieve this is by making sure that a vast majority of your diet is made up of low calorie foods such as vegetables and most fruits.

1 cup of watermelon contains only 46 calories but its high water content helps fill you up (more on that next). This is great because it means you end up feeling full faster, while consuming very few calories.

It has a lot of water

Many people mistake thirst for hunger. When you are dehydrated you feel tired and so a lot of people reach out for food, thinking it is the best option to help restore their energy levels. A better option would be to simply increase your intake of water as this would help the feeling of fatigue subside. A great way to increase your water intake is to consume water dense foods such as vegetables and fruits, watermelon included.

Increased water consumption can help with weight loss. This study showed that when overweight people drank 500 ml of water, their metabolism increased by 24% for up to an hour. That is great news if you are trying to lose weight as it means you end up burning more calories. Another study showed that when a group of people drank 500 ml of water before every meal, they ended up losing 44% more weight than a group that didn’t drink water. This is most likely due to the fact that water fills you up quicker meaning you end up eating less.

Watermelon makes for a great food to snack on and is much healthier than crisps, cookies and other junk foods. It also contains a little bit of fiber (however other fruits do contain much more) and this helps keep you full longer.

It is very sweet

The sweetness of watermelon can definitely be an advantage when you are trying to lose weight because it can help satisfy a sweet tooth. Usually people reach out to foods like chocolate and ice cream to satisfy their sweet tooth but the main problem with this is that those foods contain much more fat, sugar, cholesterol and calories than fruits and vegetables.

For example, 100 g of chocolate ice cream contains 216 calories, 7 g of saturated fat, 34 mg of cholesterol and 25 g of sugar. 100 g of watermelon contains 30 calories, 0 saturated fat, 0 cholesterol and 6 g of sugar.

So the next time you have a sugar craving, have some fruit such as watermelon, pineapple or an orange instead of sugar loaded junk foods.


Watermelon can be eaten on its own or added to salads & smoothies and should definitely be included in a weight loss diet. If you combine it with other weight loss foods, exercise regularly, stay in a calorie deficit and follow the weight loss tips here, you will begin to notice a big difference in how you look in the mirror.

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