image of watermelon keto

Is Watermelon Keto-Friendly Fruit? Everything You NEED TO KNOW!

Imagine this: it’s a scorching hot day, you have a watermelon in one hand, a lettuce-wrapped burger in the other, and your favorite sports team has just won the final in their league.

Sounds pretty dreamy right?

The prize for the most crowd-pleasing summertime fruit has to go to watermelon. Its pink, vibrant color, and refreshingly sweet juices make them a staple part of our summer diet.

However, as with all fruit, there comes the question: Is watermelon keto-friendly?

How can we incorporate watermelon into the keto diet?

Want to know a secret?

We actually have! Do we have your attention now?

Can you blame us for always craving a slice on a hot summer day? We just want to eat watermelon without affecting our ketosis!

So hold onto your bucket hats and grab your lemons, we will tell you all about how you can use watermelon in the ketogenic diet.

What Is Watermelon?

You never thought you would ever read that question, did you?

So we’ll keep it simple.

Watermelon is a refreshingly sweet, water-based low-calorie fruit that is demanded during the summer months. Not only is it hydrating, but it comes with an extensive nutritional value which we cannot wait to share with you.

Watermelon comes from the Cucurbitaceae (try saying that) family, along with cucumbers, zucchini, and honeydew. (*)

Enough with the basics, let’s delve into the reason we’re all here – watermelon’s keto compatibility!

Watermelon’s Nutritious Value

Let’s get started, shall we?

Like all fruit, watermelon comes with a variety of nutritious nutrients for us to enjoy and benefit from. The list below indicates the nutritious value that one cup of diced watermelon contains (154 g) as the USDA presents. (*)


  • Calories – 46.2
  • Fat – 0 g
  • Total Carbs – 11.6 g
  • – Fiber – 0.6 g
  • – Sugar – 9.6 g
  • – Net Carbs – 11 g
  • Protein – 0.8 g


  • Vitamin C – 12.5 mg
  • Vitamin A – 43.1 mcg
  • Lycopene – 6,980 mcg
  • Potassium – 172 mg
  • Magnesium – 15.4 mg
  • Calcium – 10.8 mg

The lists above are not limited. The nutritional value of watermelon is extensive, as, alongside these nutrients, you can find a plethora of antioxidants (choline, L-citrulline, L-arginine), essential minerals, and B vitamins that all carry out their benefits uniquely.

On that note, let’s expand on what all of these vitamins and minerals can bring to your health.

Don’t worry we know watermelon is not low-carb and we’ll talk about the 11 grams of net carbs too!

Health Benefits Of Eating Watermelon

Watermelon isn’t just a pretty taste. It comes with an overwhelming amount of health benefits.

Trust us; you’re going to WANT to know these.


Unsurprisingly, watermelon has a high water content of approximately 90% water. It is also packed full of electrolytes such as potassium, magnesium, and calcium, which help replenish our electrolyte stores.

Here’s the truth:

Water is not only essential for health but even more essential for the diet. We need water to prevent us from doing damage to our kidneys whilst on the ketogenic diet.

Vitamins and Minerals

One cup of diced watermelon contains 19.5% Vitamin C of our recommended daily amount. Studies show that Vitamin C helps maintain our body’s healthy cells and blood vessels. (*)

And as if that’s not enough, it also helps form a substance called collagen which helps with wound healing, reduction of scars and acne.

Contains Compounds That May Help Prevent Cancer

The research proposed by various authors, and the National Cancer Institute, suggests that free radicles have a role in the development of certain types of cancer. (*)

Here’s an interesting fact:

Free radicles are chemicals that are highly reactive and have the potential to seriously harm your DNA cells via oxidative stress.

Certain nutrients found in watermelon, such as Vitamin C, have a role in fighting against these free radicles and help prevent cancer.

Lycopene, another nutrient found in watermelon, has been proven to reduce the incidence of certain cancers such as prostate cancer. (*)

Blood Pressure And Cardiovascular Disease

Further studies have shown that watermelon extract reduces blood pressure, especially in and around the ankles in the elderly and those with early-onset hypertension. (*)

The researchers behind the study suggest that two of the antioxidants found in watermelon- L-citrulline and L-arginine –  cause the arteries to dilate and in turn, reduce the blood pressure.

But wait, there’s more!

As previously mentioned, lycopene, another antioxidant in watermelon has been shown to reduce cholesterol levels which coincides with the reduction in heart disease.

It’s as if every component of watermelon is working together to make us even healthier!

Lower Inflammation and Oxidative Stress

Further research on watermelon has concluded that it helps protect against certain diseases by reducing inflammation in the body. (*)

Want to know how?

Carotenoids, a certain group of antioxidants also found in watermelon have been linked to reducing oxidative stress, meaning that your body’s cells will be more oxygenated and able to carry out their functions more proficiently.

May Help Relieve Muscle Soreness

The consumption of watermelon following strenuous exercise has been shown to help with muscle soreness and speed up muscle recovery time.

Want to know the best part? We have proof!

A study carried out in 2017 showed that athletes who drank half a liter of watermelon juice with added L-citrulline had a quicker muscle recovery than those drinking the placebo. (*)

May Help Prevent Macular Degeneration

One cup of diced watermelon also contains 16.5% Vitamin A of our recommended daily amount. This helps improve our vision by preventing macular degeneration and keep our skin healthy. (*)

Furthermore, research has shown that a deficiency in lycopene has been associated with macular degeneration. It is therefore important to have a diet rich in lycopene and other antioxidants. (*)

Good for Skin and Hair

Eating one cup of diced watermelon a day can help promote hair growth. This is because the antioxidants L-citrulline and L-arginine work alongside each other, increasing blood supply to your head and therefore promote hair growth.

Better yet, watermelon can stop our hair from falling out!

Vitamin c in watermelon helps the body use a certain type of iron, promoting blood flow to your hair follicles. This strengthens your hair and prevents hair loss.

The high water content of watermelon also helps prevent your skin from dehydrating.

As mentioned above, the antioxidants present in watermelon also help prevent the function of free radicles which in turn slows down our aging process!

Can Improve Digestion And Gut Motility

We now know that watermelon is full of water. It also contains 0.6 g of fiber per cup of diced watermelon.

Both of these attributes work hand-in-hand at helping our digestive system function and prevent constipation.

Is Watermelon Considered Low-carb or Keto-Friendly?

You are now wondering how to fit watermelon into the ketogenic diet.

We’re going to explain all!

Given the diet’s restrictive nature, most fruits are somewhat forbidden to us in the keto community. So we can truly understand why incorporating certain fruits such as watermelon can come across as a challenge.

But first, we need to lay out the facts.

Carb Content: How Many Carbs in Watermelon?

Let’s recap:

When we discussed the nutritional content of watermelon, the USDA suggests that there are 11 g of net carbs in one cup of diced watermelon.

This may seem considerably high for us doing the diet, right?

Therefore, one cup of diced watermelon can take up to half of a person’s total net carb allowance if they’re sticking to a strict ketogenic diet of below 20 g of net carbs.

But wait, don’t let this alarm you!

If your ketogenic diet is more flexible and allows you to consume up to 50 g of net carbs a day, then one cup of diced watermelon contains 23.2% of your daily net carb intake. This is more reasonable and can easily be adjusted into the ketogenic diet.

Glycaemic Index (GI) Of Watermelon

The GI is a scale of 0-100 that compares the sugar content of foods to that of pure glucose, which is 100.

The GI of watermelon is around a whopping 76! This means that its relatively high sugar content can cause an insulin spike, causing more sugars and glucose to roam around the body.

So What Does This All Mean For You?

In truth, it is with our deepest regret to inform you that watermelon is not ketogenic, and therefore not recommended if you’re doing the ketogenic diet.

However, if you’re willing to monitor your macronutrients and count your net carbs, then you may allow yourself the consumption of half a cup of diced watermelon a day, to minimize your intake of daily carbs.

And what you should also know…

How Much Watermelon Can You Eat on Keto?

Take note of your metabolism! If you know that you have a slow metabolism, then make sure that you avoid watermelon. If your metabolism is fast, then you may have watermelon in the ketogenic diet in moderation.

How Can I Add Watermelon To My Keto Diet?

Do you want to learn how to use watermelon in a keto-friendly way?

Then look no further! Luckily for you, we have made a shortlist on the best ways we believe you can add watermelon to your ketogenic diet.

Juicing: You can try blending a small portion of the cup of diced watermelon with a few ice cubes. This gives you a refreshing summer beverage without taking in too many carbs.

Salad: By adding half a cup of diced watermelon to your salad, with a squeeze of fresh lemon, mint, mozzarella and spinach, you will have yourself a beautiful keto-friendly salad.

Watermelon seeds: The watermelon seeds are delicious, so don’t throw them out! Simply roast the seeds for around 20 minutes, and you have a tasty snack.

Did you know that one portion (28.5 g) of watermelon seeds contains 8 g of protein?

Do be careful in stores when buying watermelon products such as juice and ‘natural candies.’ These products tend to be fortified with excess sugar and therefore are rendered unhealthy and not keto-friendly.

Does Watermelon Have A Bad Side?

So let’s get down to it. Watermelon, like any other food, can still pose some risks to us.


Unfortunately, due to the high glycemic index of watermelon, people with diabetes may have an increased spike in their blood sugar. When watermelon is had as a juice, the fibers are removed, making the sugar easier to absorb.

Remember, if you have diabetes, watch the sugar content and monitor your blood glucose regularly.


There are people out there allergic to watermelon. Eating watermelon could trigger allergic reactions such as hives, swelling of the limbs, and even an anaphylactic reaction.

Low Carb Fruits Alternative:

If you’re not convinced by the above information and looking for a fruit similar to watermelon to substitute in the keto diet, took no further! We’re going to list to you some of our favorite alternatives.

So let’s jump right in!

  • Guava – Did you know that each serving of one guava has only 4.9 g of net carbs? (Don’t worry, these are for another article!)
  • Cantaloupe – half a cup of diced cantaloupe contains only 5.8 g of net carbs, making them a wonderful substitute for watermelon! (*)
  • Dragon Fruit – One half of a dragon fruit, which is a rather large portion, only contains 4.5 g of net carbs! Dragon fruit is very subtle in flavor, and therefore you can add it to most fruit-based meals for added flavor and beautiful coloring!

Watermelon Can Be Used In Keto If You Be Careful

As a general rule of thumb, anyone undergoing the keto diet or deciding to start on the diet should consult with their local doctor or pharmacist if they are known to have any medical issues.

This is especially important for people with diabetes or hypertension.

In addition to hydrating your body thanks to its high water volume, watermelon is also packed full of nutritional vitamins, minerals, and antioxidants.

In essence, the addition of watermelon into the keto diet can be possible, as long as you moderate the amount you decide to eat or use!

Will Watermelon Knock Me Out of Ketosis?

If you are following a strict keto diet of only 20 g of net carbs per day, then one cup of diced watermelon can take up to almost half of your daily allowance! Watermelon is therefore not ketogenic due to its high sugar and net carb content.

The Bottom Line

The good news is that depending on how you personally set out your carbs for the day; you can fit watermelon into the keto diet.

However, the bad news is that it can potentially account for half of your daily net carb allowance. This means that you should take this fact into account before you can apply watermelon carefully.

If you know you have a slower metabolism, then you should avoid watermelon and prevent unnecessary sugars in your body. If your metabolism is quick, then feel free to add watermelon to your keto diet.

The bottom line is:

Watermelon contains less net carbs per serving than most conventional fruit out there, such as bananas and apples. If you are looking for a more keto-friendly option, then consider adding fruits such as berries, guava, and cantaloupe to your diet.

image of Is Watermelon Considered Low-carb Keto-Friendly (1)

Leave a Comment

Your email address will not be published. Required fields are marked *

Scroll to Top