Is Grapefruit Keto-Friendly? Carbs in Grapefruit

Is grapefruit keto-friendly? No, grapefruit is not keto; one contains around 21 grams of net carbs, which can trigger blood sugar spikes and push you out of ketosis. 

And, what’s more, grapefruits contain compounds that may interfere with the metabolism of certain medications, increasing the risk of side effects and drug toxicity.

Learn about low-carb fruit options that won’t disrupt fat burning.

How many carbs are in grapefruit?

Grapefruit is a popular citrus fruit and an exceptionally rich source of vitamin C. Because of its tangy and slightly bitter flavor, and grapefruit is often believed to be a keto-friendly fruit. 

However, this isn’t correct. While pink and red grapefruits have a lower carb count than other citrus fruits, such as oranges and mandarins, they contain too many carbs to be on the keto food list.  

Grapefruit nutrition facts

A grapefruit's exact amount of carbs depends on the variety, size, and ripeness. 

According to data published by the U.S. Department of Agriculture (USDA), a medium-sized pink grapefruit (230 grams) typically contains:

• 97 calories 

• 0 g total fat

• 2 g protein

• 25 g total carbs

  • 4 g fiber

  • 21 g net carbs

Watch the video below to learn why it's best to avoid eating grapefruit on keto. 

Can you eat grapefruit on keto?

No, grapefruit isn’t suitable for a low-carb diet. 

To maintain ketosis and benefit from the profound metabolic changes triggered by burning fat instead of sugar, it's important to limit your daily net carb intake to 20 to 50 grams. 

Consuming grapefruits can quickly exceed your daily net carb count, which can interfere with ketone production and may inhibit or slow down ketosis. 

Can you have grapefruit juice on keto?

Grapefruit juice isn’t a good option if you are trying to limit your carb intake. 

Juicing removes grapefruit’s dietary fiber, which concentrates the natural sugar content and explains why one eight-ounce glass (240 milliliters) of freshly squeezed grapefruit juice can contain as much as 25 grams of net carbs.

Grapefruit and medication interactions

“Consuming grapefruit or grapefruit juice can potentially interfere with the metabolism of certain drugs, which increases the risk of side effects and may even cause toxicity,” explains Dr. Berg.

Grapefruits contain furanocoumarins, an organic compound that binds to a group of enzymes known as Cytochrome P450. These enzymes are located in the liver and small intestines and play a vital role in regulating how quickly toxins and drugs can enter the circulation. 

When furanocoumarins bind to Cytochrome P450 enzymes, certain drugs can freely enter the bloodstream in much higher concentrations. This significantly increases the risk of potential side effects and may cause excessive circulating levels of pharmaceutical drugs. 

Some common examples of medications affected by grapefruit consumption include:

• Statins 

• Antidepressants 

• Blood pressure medication

• Anti-anxiety drugs 

A study published in the Canadian Medical Association Journal concludes, "One whole grapefruit or 200 milliliter of grapefruit juice is sufficient to cause clinically relevant increased systemic drug concentration and subsequent adverse effects.”

If you are taking prescription medication and are concerned about potential interactions with grapefruit, it’s crucial to consult with a healthcare provider or pharmacist for specific guidance. 

Best fruit to have on a ketogenic diet

Whether a fruit is keto-friendly depends on its carb and fiber content, and understanding how to calculate the net carbs of fruits and berries is crucial for keto success.    

Here are low-carb fruit options that are on the Healthy Keto®-approved Food List:

• Blueberries

• Chokeberries

• Blackberries

• Lemon

• Lime

• Raspberries

• Red currant

• Strawberries

• Tart cherries

While berries are naturally high in fiber and low in carbs, it’s important to include them in your net carb count to avoid exceeding your daily carb limit, which can potentially disrupt ketone production and interfere with ketosis. 

Three benefits of citrus on keto 

Lemons and limes are excellent keto-approved grapefruit alternatives. Not only do lemons and limes help to satisfy grapefruit cravings, but drinking lemon water has profound health benefits.

Here are three benefits of citrus on keto.

1. Lower risk of kidney stones

Citrus fruits are naturally high in citrate, an organic compound that may help to prevent the formation of kidney stones. 

Citrate binds to calcium in the urine, which inhibits the formation of calcium oxalate, the most predominant type of kidney stone.  

2. Weight loss

Lemons and limes are rich sources of citrus flavonoids, a group of phytochemicals that promote metabolic health and support weight loss.

A study published in the Journal of Clinical Biochemistry and Nutrition found that citrus flavonoids enhance insulin sensitivity, thereby reducing the risk of insulin resistance, a metabolic imbalance linked to weight gain and difficulty losing weight.  

3. Supports healthy digestion 

Citrus may promote the activity of enzymes involved in the production and release of bile, which plays a crucial role in the breakdown and absorption of dietary fats.

Promoting bile flow aids digestion, enhances the absorption of fat-soluble vitamins, and may prevent bile sludge and gallstones. 

Key takeaways

Is grapefruit keto-friendly? No, one grapefruit contains as much as 25 grams of net carbs, which can quickly exceed your daily net carb count and interfere with fat burning and ketosis. 

Luckily, there are several keto-approved alternatives that you can enjoy on a low-carb diet, such as lemons, limes, blueberries, blackberries, strawberries, and raspberries.   

FAQ

1. Is grapefruit okay on a low-carb diet?

No, grapefruit contains too many carbs to be considered a low-carb fruit that’s suitable for a ketogenic diet. 

2. Does grapefruit contain carbs?

Yes, grapefruit contains carbs. How many net carbs a grapefruit has depends on its variety, ripeness, and size.  

Half a grapefruit (medium-sized) typically contains around 13 grams of carbs, and eight ounces of grapefruit juice can have as much as 25 grams of net carbs. 

3. What fruits are off-limits on keto?

Fruits with a high carbohydrate content, such as bananas, grapes, mangos, apples, oranges, and pineapples, are not considered keto-friendly. 

4. Which citrus fruits kick you out of ketosis?

High-carb citrus fruits, including oranges, tangerines, clementines, and grapefruits, can quickly exceed your daily net carb limit, which can disrupt fat burning and potentially kick you out of ketosis.  

5. What kind of citrus is keto-friendly?

Lemons and limes are keto-friendly citrus fruits that won’t interfere with ketosis if consumed in moderation. 

6. Which fruits will not kick you out of ketosis?

Lemons, limes, and low-carb berries such as blackberries, raspberries, blueberries, chokeberries, and red currants won’t interfere with ketosis.

However, it’s important to remember that berries contain some carbs, and it’s important to include them in your daily net carb count to avoid spikes in blood sugar and insulin levels, which can potentially disrupt fat-burning and slow down ketosis.    

7. Can grapefruit interact with my medications?

Yes, grapefruit can interact with medications. 

Grapefruit contains organic compounds that interfere with a group of enzymes responsible for the metabolism of drugs, including statins, antidepressants, and blood pressure medications. Consuming grapefruit in combination with these drugs can increase the risk of side effects and may cause toxicity. 

8. How many carbs are in grapefruit juice?

An eight-ounce glass of freshly squeezed grapefruit juice typically contains around 25 grams of net carbs. 

9. How much grapefruit can you have on keto?

Grapefruit is generally not considered a keto-friendly fruit due to its high carb count. However, if you occasionally enjoy the tart and bitter taste of grapefruit, it’s important to include its carb content into your daily net carb count to avoid excessive carb intake, which can inhibit fat-burning and kick you out of ketosis.   

10. Is grapefruit keto-friendly? 

No, grapefruit isn’t considered a keto-friendly fruit due to its high carb count. 

One medium-sized grapefruit or one eight-ounce glass of grapefruit juice typically contains around 25 grams of carbs, which can quickly exceed your daily net carb count and kick you out of ketosis.