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Is Grapefruit Keto-Friendly? (& Better Substitutes)

On the ketogenic diet the goal is to keep your carbohydrate intake low enough. What about grapefruit, is it keto-friendly?

Grapefruit is a citrus fruit known for its distinctive sour/sweet/bitter taste. This fruit is mostly consumed on its own, as a snack or dessert, or as grapefruit juice.

The net amount of carbs, which comes down to total carbs minus carbs from fiber, in raw grapefruit is around 9.1 grams per 100 grams.

While it depends on the rest of your diet, for most people grapefruit is not very keto-friendly. This fruit is not completely off-limits but you will have to exercise some portion control.

In any case, there are many substitutes for grapefruit that are better for staying in ketosis.

When is a food keto-friendly

The goal of the ketogenic diet is to put your body into ketosis, a state where it starts mainly burning fat as a fuel (1). This comes down to more or less getting 55%-60% of your macronutrients from fat, 30%-35% from protein, and 5%-10% from carbohydrates.

For most people this comes down to eating around 20g – 50g of carbohydrates a day.

In reality, this number is different depending on a lot of factors. For example, people who exercise a lot may be able to consume more carbohydrates before getting kicked out of ketosis.

That being said that daily amount can be a good general guideline.

It is also common to exclude fiber from this amount since it doesn’t get absorbed into your body the same way as regular carbohydrates.

Carbs in grapefruit

100 grams of grapefruit contains the following amounts of carbs (2):

  • Total carbs: 10.7 grams
  • Of which fiber: 1.6 grams
  • Net carbs: 9.1 grams

Combined with the other foods in your diet the 9.1 grams of net carbs in 100 grams of grapefruit can be enough to kick you out of ketosis.

One ounce of grapefruit is about 28 grams and contains the following amounts of carbs:

  • Total carbs: 3 grams
  • Of which fiber: 0.4 grams
  • Net carbs: 2.6 grams

The number of net carbs in 1 ounce of grapefruit, 2.6 grams, is a bit easier to fit into a keto diet. Whether or not grapefruit is keto for you ultimately depends on your individual situation and the rest of your diet.

Carbs in grapefruit juice

The above amounts of net carbs in grapefruit are with regular raw grapefruit. You can also consume grapefruit as grapefruit juice but this will impact how keto-friendly it is.

Here is the comparison between raw grapefruit and grapefruit juice as an example (2, 3).

Values Per 100gRaw GrapefruitGrapefruit Juice
Total Carbohydrates10.7 g9.2 g
Of Which Fiber1.6 g0.2 g
Net Carbs9.1 g9.2 g
Chart of carbs in raw grapefruit vs grapefruit juice

As you can see, if you decide to eat grapefruit on the ketogenic diet, you preferably want to eat it raw, not as grapefruit juice. That being said the difference in net carbs between these two nutritional value examples is not that big.

You do have to keep in mind that this example of grapefruit juice is without added sugar. Many grapefruit juice brands do add sugar which makes this drink higher in net carbs and thus less keto-friendly.

Other nutrients in grapefruit

Other nutrients like fat, protein, vitamins, and minerals also still matter on the ketogenic diet.

100 grams of raw grapefruit contains the following nutrients (2):

  • Calories: 42
  • Protein: 0.8 grams
  • Carbs: 10.7 grams
  • Part of the carbs that is fiber: 1.6 grams
  • Fat: 0.1 grams
  • Vitamin C: 52% of the DV (Daily Value)
  • Vitamin A: 23% of the DV
  • Potassium: 4% of the DV
  • Thiamin: 3% of the DV
  • Vitamin B6: 3% of the DV

And some other vitamins and minerals in smaller amounts.

On top of being slightly higher in net carbs, grapefruit does not contain that many valuable nutrients per 100 grams compared to many other foods.

How to avoid eating too much grapefruit

By now it is clear that to be able to fit grapefruit in your keto diet, you will have to exercise some portion control. Having a big bowl of peeled grapefruits near you and hoping that you don’t eat too much is not the ideal way to do this.

You can avoid eating too much grapefruit with some of the following tips:

  • Plan ahead, how much grapefruit will you eat?
  • Put the planned amount in a bowl and leave the rest of the grapefruit out of sight
  • Don’t eat during other activities like watching TV
  • Consider not buying it if you can’t control yourself

If you notice you get out of ketosis you may need to reduce the quantity of grapefruit you eat.

Substitutes for grapefruit on keto

Grapefruit is not the only option when you want to eat fruit on the ketogenic diet. Grapefruit is not the highest in net carbs but there are many fruits that are more keto-friendly.

Some of the following substitutes may be better on the keto diet. These are the net carb values per 100 grams (4, 5, 6, 7, 8, 9):

  • Blackberries: 4.9 grams of net carbs
  • Raspberries: 5.4 grams of net carbs
  • Strawberries: 5.7 grams of net carbs
  • Watermelon: 7.1 grams of net carbs
  • Cranberries: 7.6 grams of net carbs
  • Cantaloupe: 7.9 grams of net carbs

If you have trouble staying in ketosis but still have cravings for fruit it may be smart to choose some of these substitutes over grapefruit. However, even with these examples you will have to exercise portion control to stay in ketosis.

What is your goal with keto?

Even a small portion of grapefruit added to certain daily diets can potentially put you just over the net carbs border, out of ketosis. Depending on the goal you have with keto this may or may not be a problem.

If your goal is to stay strictly in ketosis 24/7 you want to be careful about your carbohydrate intake.

If your goal is to lose weight and become healthier, grapefruit can be a good food option even if it potentially puts you at a carbohydrate level slightly above your ketosis level. Even if you are just trying to lose weight grapefruit juice is generally not recommended.