Grapefruit is a nutritious fruit that is low in carbs and calories, making it a popular choice for low carb and ketogenic diets. However, there has been some debate over whether grapefruit is suitable for a low carb lifestyle. This article examines the carbs and calories in grapefruit, the effects it has on weight loss and metabolism, and whether there are any downsides to eating grapefruit on a low carb diet.
Carbs and Calories in Grapefruit
One medium grapefruit (approx. 184 grams) contains:
- Calories: 74
- Total carbs: 15 grams
- Fiber: 2 grams
- Sugar: 11 grams
- Net carbs: 13 grams
The majority of the carbs in grapefruit come from natural sugars like sucrose, glucose, and fructose. However, grapefruit is considered a low glycemic fruit because its sugars have little effect on blood sugar levels.
It provides only 13 net grams of carbs per serving, which is very low compared to other fruits. For comparison, a medium banana contains 27 grams of net carbs.
Given its low carb content, grapefruit can easily be incorporated into a low carb diet providing less than 50-100 grams of total carbs per day.
Effects on Weight Loss
Eating grapefruit has been associated with weight loss for several reasons:
- Low calorie density – With only 74 calories per medium fruit, grapefruit is 90% water and low in calorie density. This makes it filling for few calories.
- High fiber – The fiber content of grapefruit may increase feelings of fullness and help reduce calorie intake.
- Nutrient-dense – Grapefruit contains important vitamins, minerals, and antioxidants with few calories.
- Low glycemic impact – The natural sugars in grapefruit have a negligible effect on blood sugar and insulin levels, which can aid fat burning.
Some small studies have found grapefruit juice or half a grapefruit before meals can lead to significant weight loss compared to placebo groups.
However, other studies have found mixed results. A review of 17 studies concluded that grapefruit can induce modest weight loss but does not have a strong clinical relevance for weight management.
Overall, eating grapefruit may provide a benefit for weight loss, especially when paired with a healthy diet and active lifestyle. But the effects are likely to be modest.
Effects on Metabolism
Grapefruit contains a compound called naringin that may have beneficial effects on metabolism:
- Increases fat burning – Animal studies suggest naringin can increase lipolysis (fat breakdown) and improve insulin sensitivity in muscle and liver cells.
- Lowers insulin levels – Naringin and other grapefruit flavonoids can improve insulin sensitivity and lower insulin levels needed for blood sugar control.
- Increases metabolism – Animal studies show grapefruit extract may increase energy expenditure from greater fat metabolism.
- Reduces appetite – Grapefruit metabolites may suppress appetite signals in the brain, reducing calorie intake.
However, human studies are lacking, and the effects of grapefruit compounds on metabolism in humans remain unclear.
Downsides of Grapefruit on Low Carb
There are a few potential downsides to keep in mind when eating grapefruit on a low carb diet:
- Sugar content – While low glycemic, grapefruit is still relatively high in sugar and may not be suitable for very low carb diets under 50 grams of carbs per day.
- Can spike blood sugar – The sugars in grapefruit can potentially cause a rise in blood sugar, particularly in diabetes. Check with your doctor if you have diabetes.
- Some medications – Grapefruit can interact with several medications by inhibiting cytochrome P450, so check with your doctor about medication interactions.
- Acidic – Grapefruit has high acidity, which could aggravate issues like acid reflux or heartburn.
As long as you account for the carbs, grapefruit is unlikely to knock you out of ketosis. But it may be unsuitable for very low carb or keto diets under 20-30 grams of net carbs per day due to the natural sugar content.
Is Grapefruit Keto-Friendly?
The keto diet typically limits carbs to 20-50 grams per day to induce ketosis.
With 13 grams of net carbs in half a medium grapefruit, it can easily fit into a keto diet. But you may want to eat smaller portions to keep total carbs low for the day.
Here is how you can incorporate grapefruit into a keto diet:
- Eat just half or a quarter grapefruit at a time
- Pair it with high fat foods like avocado or nut butter
- Drink grapefruit juice in moderation or avoid altogether
- Mix some grapefruit sections into a salad
Overall, grapefruit is a keto-friendly fruit choice, though limiting intake to half a grapefruit or less per day can help keep carbs low.
Grapefruit Nutrition Facts
Here are some key nutrients found in 1 medium grapefruit (184 grams):
| Nutrient | Amount | % Daily Value |
|---|---|---|
| Calories | 74 | 4% |
| Protein | 1.5 g | 3% |
| Carbs | 15 g | 5% |
| Fiber | 2 g | 7% |
| Calcium | 22 mg | 2% |
| Iron | 0.15 mg | 1% |
| Potassium | 288 mg | 6% |
| Vitamin C | 78 mg | 130% |
| Vitamin A | 1253 IU | 25% |
Grapefruit is an excellent source of vitamin C and vitamin A. It also provides small amounts of potassium, B vitamins, calcium, and other trace nutrients.
Health Benefits of Grapefruit
Here are some of the main health benefits associated with eating grapefruit:
- High in antioxidants – Grapefruit contains powerful antioxidants like vitamin C, lycopene, and choline that can protect against cellular damage from free radicals.
- May support weight loss – As discussed earlier, compounds in grapefruit may boost fat burning, reduce appetite, and support weight loss when paired with a healthy diet.
- Lowers blood sugar – Grapefruit may improve insulin resistance and lower blood sugar levels and diabetes risk.
- Boosts immunity – The vitamin C content of grapefruit acts as an immune system booster.
- Improves heart health – The nutrients in grapefruit may reduce blood pressure, blood cholesterol, and heart disease risk.
- Fights cancer – Grapefruit contains compounds like naringenin that exhibit anti-cancer effects in studies.
- Healthy hydration – Grapefruit is 90% water, allowing it to effectively hydrate the body.
However, human studies are lacking for many potential health benefits, and more research is needed.
Tips for Eating Grapefruit on Low Carb
Here are some tips for enjoying grapefruit on a low carb diet:
- Add some cinnamon or ginger powder on top for extra flavor.
- Sweeten with a small amount of low carb sweetener if needed.
- Buy fresher grapefruit during peak season in winter and spring.
- Mix sections into a spinach or kale salad.
- Drink unsweetened grapefruit juice in moderation.
- Choose white, pink, or ruby red grapefruit varieties.
- Pair it with high fat foods like nuts, seeds, or avocado.
- Eat only half a medium grapefruit or less per serving.
Potential Grapefruit Interactions
Grapefruit can interact with a number of common medications. This is due to compounds in grapefruit that inhibit cytochrome P450, an enzyme system that metabolizes medications.
Drug classes that may interact with grapefruit include:
- Statins
- Anti-arrhythmia medications
- Immunosuppressants
- Benzodiazepines
- Antibiotics
- Antidepressants
- Anti-seizure medicines
- Opioid pain medications
- Sildenafil (Viagra)
- Calcium channel blockers
Grapefruit interactions can increase drug absorption and blood concentrations to potentially dangerous levels. Speak to your healthcare provider about any possible grapefruit interactions if you are taking medications.
Frequently Asked Questions
Is grapefruit good for weight loss?
Grapefruit may modestly aid in weight loss due to its low calorie, high fiber, and low glycemic properties. Compounds in grapefruit may also boost metabolism and fat burning. Eating grapefruit before meals could induce slight weight loss.
Can you have grapefruit on the keto diet?
Yes, grapefruit fits into a keto diet providing it accounts for total daily carb intake. Limit intake to half a medium grapefruit at a time to keep net carbs under 50 grams per day for ketosis.
Is grapefruit high in sugar?
Grapefruit contains around 11 grams of natural sugars per medium fruit, mainly glucose and fructose. So it’s relatively high in sugars compared to other low carb fruits. But it has a low glycemic impact due to its fiber content.
What is the lowest carb fruit?
The lowest carb fruits include: avocado, olives, blackberries, raspberries, strawberries, coconut, starfruit, lemons, limes, and cantaloupe. These provide only around 0-4 grams of net carbs per serving.
Is grapefruit bad for cholesterol?
No, studies show grapefruit can lower LDL (bad) cholesterol, reduce blood triglycerides, and protect the heart. The vitamin C, lycopene, fiber, and other plant compounds in grapefruit benefit cholesterol levels.
The Bottom Line
Grapefruit is a nutritious, low calorie, low carb fruit that can be enjoyed as part of a healthy low carb or ketogenic diet. It provides antioxidants, metabolism-boosting compounds, and health benefits for weight loss, diabetes, and heart disease.
While grapefruit is relatively high in natural sugars compared to other fruits, its low glycemic impact allows it to fit into diets with less than 50-100 grams of carbs per day.
Enjoy grapefruit in moderation, pair it with fatty foods, and limit intake to half a medium grapefruit or less per serving to make it work for a low carb lifestyle.
