Are Bananas Safe On The Ketogenic Diet?

On the ketogenic diet, you have to restrict your carbohydrate intake so that your body enters a state called “ketosis.”

When in this state, your body starts using fat for energy instead of glucose.

When there are limited carbohydrates available (which would normally be the primary fuel source), the liver converts fatty acids into molecules called “ketones.” It releases them into the bloodstream, where cells can use them as an alternative fuel source.

It takes about 3-4 days for a person’s body to enter this keto-adapted state. Once it does, most people experience increased mental clarity and focus while also having more consistent energy levels throughout the day.

However, it can take up to two weeks before they enter ketosis for some people, so don’t worry if you are not in ketosis right away.

Many foods have a moderate to high amount of carbohydrates (5% or higher), making them unsuitable for the ketogenic diet and should be avoided on this type of diet.

A medium-sized banana is about 27 grams of total carbs. This means if you have a daily limit of 50 grams of carbs for the ketogenic diet, eating one banana would likely knock you out of ketosis.

Banana Nutrition Facts

Bananas are an excellent source of Vitamin B6, Vitamin C, and Potassium.

They also contain differing amounts of many other vitamins and minerals depending on the stage of ripeness when they are consumed. Bananas also contain tryptophan, a precursor to the neurotransmitter serotonin, making you feel relaxed and improve your mood.

In addition to the above, they are also a good source of fiber and antioxidants.

Since bananas have some very positive attributes, it’s important to know what you can and cannot eat on the keto diet to not knock yourself out of ketosis.

Bananas Contain Sugar

Although most people are aware that bananas contain sugar, many people don’t realize that the amount of sugar in a banana is quite significant.

When you eat a medium-sized banana (27 grams of total carbs), there are actually 14 grams of natural sugar.

This is the natural sugar in a banana, which you will need to avoid on a ketogenic diet. The remaining 13 grams of carbs come from things like fiber and other compounds.

Related: Is There A Direct Link Between Cancer And Sugar?

Eating Banana On A Low-Carb Diet

If you are a low-carber, you may be wondering if it is OK to eat bananas when trying to lose weight.

Before we get into the answer, let’s look at some of the other things that bananas contain. Included in this list are:

  • Proteins – 1 gram
  • Fats – 0 grams
  • Sodium – 1 milligram
  • Fiber – 3 grams
  • Vitamins

If you are looking for the micronutrients in a banana, they have trace amounts of:

  • Potassium
  • Calcium
  • Magnesium
  • Iron
  • Phosphorus
  • Manganese
  • Copper
  • Selenium
  • Vitamins A, C, and B6

However, how your body processes the sugar in a banana will be different from how sucrose and other carbohydrates are digested.

Carbs break down into glucose as they are metabolized, and then the glucose is transported to cells in your body via the bloodstream.

This is why when you eat carbohydrates, they spike your blood sugar levels, which trigger insulin to be released by the pancreas to bring those levels back down (which it does by storing any excess energy that is not used right away as fat on your body).

Because fruit contains a significant amount of natural sugar, this causes your blood sugar levels to rise significantly when you consume fruits.  

But once the fruit is broken down into glucose in your gut and absorbed, the same spike in blood sugar doesn’t happen because it’s already been converted into sugar.

This means that eating fruit on a low-carb diet is not ideal, although it certainly won’t knock you out of ketosis by itself.

But when you combine the sugar in fruits with all the other sources of natural and unnatural sugars that are in almost every processed food, as well as any potential carbs from hidden sources like grains and legumes, this can become a severe problem, causing you to experience all the metabolic consequences that come along with it.

The only fruits that are good for low-carb diets in moderation (about one serving per day) are berries like blueberries, strawberries, and blackberries.

However, these should only be eaten when they are in season because they are very high in antioxidants that lose their potency when they are overly processed and shipped worldwide.


Since bananas contain high amounts of carbohydrates, they are not recommended on the ketogenic diet.

Although bananas have positive health benefits since they’re a good source of antioxidants and fiber, and contain tryptophan, a precursor to the neurotransmitter serotonin, which can make you feel relaxed and improve your mood, they can still kick you out of ketosis if you’re not careful.

Although most people are aware that bananas contain sugar, many people don’t realize that the amount of sugar in a banana is quite significant. For example, when you eat a medium-sized banana (of total carbs), there are actually 14 grams of natural sugar, but around 27 grams of carbs in total, depending on the size.  

When you eat too many carbohydrates, including those from bananas, you can create an oversupply of insulin, which causes your body to stop using the fat stored as a source of energy. The excess sugar that bananas contain affects you similarly, but to a lesser extent since it’s a natural fruit and not a refined carbohydrate from grains or legumes.

For the most part, eating a banana or two once in a while will not affect your ketosis too much, but it’s best to avoid bananas if you want to get into and maintain optimal ketosis.

If you are following a strict low-carb diet, it’s important to know that although they are fruits and contain vitamins, minerals, and fiber, they also have high amounts of carbohydrates that you should try to avoid.

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