Is watermelon Keto? – How much watermelon allowed on keto diet?

Watermelon is delicious, healthy, and refreshing food.

Watermelon is filled with vitamin C, A, and lots of other healthy nutrients. It contains high water content. So, it is a very delicious way to keep your body hydrated especially in summer. [1]

Now the question arises, should you eat watermelon on the keto diet?

Does the nutrition of watermelon fit with a keto diet?

Its nutrition can fit with a keto diet you just need to eye on the servings you are taking.

1 cup (154) of watermelon contains 11g total carbs and 9g sugar or 100 g watermelon contains 7g carbs and 6g sugar, according to USDA Food Composition Databases.

92% of its weight is due to water content. It is also low in calories. It is high in vitamins A and C. it is also a great source of magnesium and potassium

Watermelon content per 100g, according to USDA Food Composition Databases

  • Carbs 7.55g
  • Sugar 6.2g
  • Water  92g
  • Calories 30
  • Protein  0.5
  • Fiber  0.4g

Vitamin and minerals

  • Calcium 7mg (1% of DV)
  • Magnesium 10mg (2% of DV)
  • Potassium  112mg (3% of DV)
  • Vitamin C 8.1mg  (13 of DV)
  • Vitamin A   569IU (11% of DV)

Watermelon also contains other vitamins and minerals such as thiamine, vitamin B6, riboflavin, niacin, folate, pantothenic acid, magnesium, zinc copper, selenium, lycopene, betaine, and choline. Watermelon contains lycopene more than any other fruit.

How many carbs in watermelon?

For the keto diet, net carbs content is the most important aspect of the food than fat. Only net carbs can kick you out of ketosis.

When it comes to fruits net-carb is the most important factor because fruits are generally low in fat.

Watermelon contains 90% calories and 90% calories come from net carbs.  

Net carbs in watermelon

Amount Net carbs
100g watermelon7g
1 small slice (71g)5g 
10 watermelon balls (152g)9.2g
1 cup (152g)11g
1 medium slice (286g)20g
1 large slice (572g)41g
1 medium Melone (3200g)242g
1 large melon (6kg)453g

SourceUSDA Food Composition Database

Is watermelon keto-friendly?

Yes, watermelon is keto-friendly, but in a low amount of less than 100g. Watermelons contain lower carbs than other fruits, so you can add one slice or 100g watermelons to your keto diet.

Generally, fruits are restricted in the keto diet because they are higher in carbs and fructose.

Watermelon is relatively lower in carbs than other fruits. 100g watermelon contains 7g carbs. But this is just one side.

The glycemic index also takes part in ketosis.

  • Glycemic index (the speed at which it elevates the sugar level in blood) = 72
  • Glycemic load (the quantity of carb present in food) = 4

The glycemic index of watermelon is high. It gives a sudden spike of sugar in your blood, which is bad for ketosis which can kick you out of ketosis.

But the good thing is that the glycemic load of watermelon is low as long as you are eating Melone in a lower amount.

Net carbs and sugar in watermelon

AmountNet carbsCalories Sugar 
100g watermelon7g30 kcal6.2g
1 small slice (71g)5g 21 kcal4.4g
10 watermelon balls (152g)9.2g36.5 kcal7.5g
1 cup (152g)11g45 kcal9.4g
1 medium slice (286g)20g86 kcal17.7g
1 large slice (572g)41g172 kcal35.5g
1 medium Melone (3200g)242g960 kcal198g
1 large melon (6kg)453g1800372g

SourceUSDA Food Composition Database 

You can easily overeat watermelon. So try to avoid it as long as you can, if you want to eat. You should eat in a minimum amount.

How much watermelon can you eat on a keto diet?

As you know watermelon can easily mess with your ketosis.

You can easily overeat watermelon. So it is better to cut a watermelon into pieces before eating.

You can eat 100g watermelon or 1 small slice (71g) or 10 watermelon balls (152g) on a keto diet, in this you will be eating 7-9g net carbs.

Just 1 cup (154g) watermelon contains 11g net carbs. 

There are more than 1200 varieties of watermelon and the smallest watermelon can weigh 1 pound. An average watermelon weighs around 10-12 pounds. 

You can eat an average watermelon for almost one month.

You should eat less than 1 cup on a standard keto diet and should avoid watermelon completely during the adaptations stage.

But if you are very active during the day, which means you do exercise or exercise, then you can eat more than 1 cup. 

Test your carb tolerance level. If your metabolism is good then you can also eat up to 1 cup of watermelon a day.

But if you are less active or your metabolism is slow, try to avoid watermelon completely.

When to avoid watermelon on keto?

You can eat a slice of watermelon on a keto diet.

But, there is a certain time on a keto diet when you should not even think about eating watermelon.

If you are still trying to get into ketosis then you should completely avoid watermelon.

Watermelon can slow down your speed to get into ketosis and you want to keto into ketosis as fast as you can. 

The slower you get into ketosis longer the keto flu symptoms stay. It is low in carbs, but at the same time, its GI is also high.

Small blood glucose spikes can slow down the ketosis process, even shut off the ketosis process completely.

Before eating watermelon in a ketogenic diet, make sure you are in ketosis fully.

For this, you can test the ketone level in your body. You can check ketone in blood, urine, and breath.

But a blood test is considered more accurate.

  1. Partial ketones0.5 mmo/L. This means you are not in full ketosis yet. It is not the right time to add carbs to your diet.
  2. Optimal ketosis1.5 – 3.0 mmo/l. This means you are in optimum ketosis. You can test your carbs’ tolerance limit and try to add some carbs to your diet. This ketone zone is optimal for weight loss.

Only eat watermelon if you are in optimum ketosis or your blood ketone level more than 1.5 mmo/l.

Otherwise, restrict watermelon completely.

One more thing if your metabolism is slow and your lifestyle is sedentary, avoid watermelon. It can mess with your ketosis.

So why take the risk of just avoid watermelon during the adaptation stage and slow metabolism.

When to eat watermelon on a keto diet?

If you are already in ketosis and all the keto-flu symptoms have gone away. 

Before eating watermelon check your blood ketone level. If you are in optimum ketosis, it is a green signal to go but don’t go too fast you can easily cross the limit.

Before eating you should be able to manage the total carbs within the limit of the ketogenic diet. 

But remember you should eat watermelon in a very low amount. If you overeat, it will be a matter of time and you will be out of ketosis. 

Bonus tip

If you want to enjoy these delicious low carbs fruits and vegetables then increase your daily activity, be more active during the day. If you are living a sedentary lifestyle. You have to stay below the 20g limit and have to avoid watermelon and many other delicious foods.

How to make room for watermelon on a keto diet?

If you are already in ketosis and all the keto-flu symptoms have gone away. 

Before eating watermelon check your blood ketone level. If you are in optimum ketosis, it is a green signal to go but don’t go too fast you can easily cross the limit.

Before eating you should be able to manage the total carbs within the limit of the ketogenic diet. 

If you are following a standard keto diet then you should avoid watermelon completely, but other keto diets allow you to add some carbs in a certain window of time.

1. The targeted keto diet (TKD) – TKD allows you to add 20-30g extra carbs before or after exercise. This diet is designed for people with very active lifestyle such as an athlete.

2. The cyclic keto diet (CKD) – in CKD you follow a standard keto diet for 5 days following with 1- days of carbs refeed in which you can eat 600-1200 carbs. Again this diet is also for people with active lifestyles.

But remember you should eat watermelon in a very low amount. If you overeat, it will be a matter of time and you will be out of ketosis. 

Conclusion

Watermelon is low in carbs but its glycemic index is high. It contains easily digestible carbs. You can easily cross the limits of the total carbs limit.

Our words for you is that you should try to avoid watermelon completely during a keto diet. 

But if you decided to eat watermelon you should remember, you should not be in a keto adaption stage and try to keep a limit minimum but not more than 100g.

Most frequently asked questions

Is it OK to eat watermelon on a low carb diet?

Watermelon contains lower net carbs content than other fruits. So, you can eat a larger portion of watermelon than other fruits as long as net carbs content is below 15g net carbs.

How many carbs in watermelon?

100g watermelon contains 7g net carbs. 1 cup (152g) watermelon contains 11g net carbs. 1 medium Melon (3200g) contains 242g net carbs. 1 large melon (6kg) watermelon contains 453g net carbs.

Does watermelon kick you out of ketosis?

It is not necessary that watermelon will kick you out of ketosis. Just stick to daily carbs limit on keto diet, which is 20-50g net carbs per day.

When should you not eat watermelon?

You should not eat watermelon during bed time. Simply don’t eat watermelon after 7pm. If you are on keto then only eat after adapting ketosis fully.

Is Watermelon good for weight loss?

90% of watermelon weight is water. It is one of the best fruits to lose weight when you eat it, you gain less calories but at the same time it makes you feel full. 100g watermelon contains just 30 calories.

Is watermelon full of sugar?

Actually watermelon is full of water and fructose. If we looked at glycemic load, it is 4, which is low. It won’t spike your blood sugar level after eating it. You just need to stick small servings. Increasing servings also increase glycemic load.