Carbs in Grapefruit: Is It Keto Approved?

Medically reviewed article

Grapefruit | Carbs | Keto | Alternatives | Conclusion | FAQ

The grapefruit is a cross between an orange and a grapefruit. It is a refreshing citrus fruit, but it also tastes sweet.

Therefore, a legitimate question is whether grapefruits suit low-carb and keto diets. In the end, there must be some carbohydrates hiding in them.

Is Grapefruit Keto?

Grapefruits can be white, yellow, pink, or red. Their taste is sweet on the one hand and sour on the other. Regardless of the color, one thing is sure: grapefruits contain a lot of vitamin C.

But can grapefruits suit keto and other low-carb diets because of their carbohydrates?

To find out, we need to look closely at their nutritional values.

Carbs in Grapefruit

Grapefruits are citrus fruits. These tend to be poorer in carbohydrates. So is grapefruit not nature’s candy?

How Many Carbohydrates Are in Grapefruit?

100 grams of grapefruit provide the following average nutritional values (*):

  • Energy: 42 calories
  • Protein: 0.77 grams
  • Fat: 0.14 grams
  • Carbohydrates: 10.7 grams
  • Dietary fiber: 1.6 grams
  • Net carbs: 9.1 grams

According to nutritional information, carbohydrates predominate in grapefruits. They are also free of fat and protein.

In short, grapefruits are a high-carbohydrate, low-fat food. So grapefruits are not precisely what we prefer in a ketogenic diet. They have a fat-to-net carbohydrate ratio of less than 0.02.

Grapefruit is not suitable for keto

Is Grapefruit Keto-Friendly?

Grapefruits are not well suited for the ketogenic diet. Just one grapefruit can kick you out of ketosis, as it contains 20-25 grams of net carbohydrates.

It contains about 9 grams of sucrose and an additional 4 grams each of glucose and fructose (*).

Sucrose is what we think of as table sugar. This ordinary sugar consists of 50% glucose and 50% fructose.

Therefore, one grapefruit provides about 17 grams of table sugar. 91% of the calories in grapefruits come from sugar.

Especially when grapefruits are enjoyed as juice, they promote blood sugar, insulin levels, and fat gain (Teff et al. 20041Meijssen et al. 20012Chandalia et al. 20003).

Is Grapefruit Healthy?

According to nutritional information, grapefruits are high in sugar. Therefore, is it perhaps the vitamins that make grapefruits healthy?

Just one grapefruit can provide the entire daily requirement of vitamin C, but that’s about it. Grapefruits contain no other vitamins or minerals worth mentioning (*).

Even beta-carotene, often erroneously reported as vitamin A, can only be converted by the body in small amounts, covering about 3% of the daily requirement (Hickenbottom et al. 20024).

Grapefruits are first-class vitamin C donors. Therefore, they are healthier than apples, which contain no significant amounts of vitamins. Nevertheless, they are by no means natural multivitamins. In contrast, offal, such as liver, and selected vegetables, deserve this title.

In the case of fruits, it is mainly the marketing that is healthy.

Keto Alternatives to Grapefruit

If you don’t want to miss the sweet and sour grapefruit refreshment on keto, you’re better off with limes in moderation. They perform about as well as lemons (*,*).

An even better low-carb alternative is raspberries. They contain fewer net carbohydrates and are richer in fiber, vitamins, and minerals (*).

Due to Carbs, Grapefruit Is Not Keto

Among citrus fruits, grapefruits are the worst choice regarding carbohydrates. Especially when separated from their fiber, e.g., juiced, they can stop ketosis instantly.

Grapefruits are not suitable for keto or any other low-carb diet. One bite is acceptable, but not much more. Limes or raspberries are better alternatives.

grapefruits are high in carbs

Carbs in Grapefruit: Is It Keto FAQ

Is grapefruit OK on a low-carb diet?

Grapefruits contain a lot of sugar and are poorly suited for low-carb diets and weight loss.

Is fresh grapefruit juice keto-friendly?

The sugar is separated from the fiber with juices, leading to a blood sugar spike. Therefore, fresh grapefruit juice is not keto-friendly.

Do grapefruit have carbs?

Over 90% of the calories in grapefruit are carbohydrates.


1Teff KL, Elliott SS, Tschöp M, Kieffer TJ, Rader D, Heiman M, Townsend RR, Keim NL, D’Alessio D, Havel PJ. Dietary fructose reduces circulating insulin and leptin, attenuates postprandial suppression of ghrelin, and increases triglycerides in women. J Clin Endocrinol Metab. 2004 Jun;89(6):2963-72. doi: 10.1210/jc.2003-031855. PubMed PMID: 15181085.

2Meijssen S, Cabezas MC, Ballieux CG, Derksen RJ, Bilecen S, Erkelens DW. Insulin mediated inhibition of hormone sensitive lipase activity in vivo in relation to endogenous catecholamines in healthy subjects. J Clin Endocrinol Metab. 2001 Sep;86(9):4193-7. doi: 10.1210/jcem.86.9.7794. PubMed PMID: 11549649.

3Chandalia M, Garg A, Lutjohann D, von Bergmann K, Grundy SM, Brinkley LJ. Beneficial effects of high dietary fiber intake in patients with type 2 diabetes mellitus. N Engl J Med. 2000 May 11;342(19):1392-8. doi: 10.1056/NEJM200005113421903. PubMed PMID: 10805824.

4Hickenbottom SJ, Follett JR, Lin Y, Dueker SR, Burri BJ, Neidlinger TR, Clifford AJ. Variability in conversion of beta-carotene to vitamin A in men as measured by using a double-tracer study design. Am J Clin Nutr. 2002 May;75(5):900-7. doi: 10.1093/ajcn/75.5.900. PMID: 11976165.

Mag. Stephan Lederer, MSc. is an author and blogger from Austria who writes in-depth content about health and nutrition. His book series on Interval Fasting landed #1 on the bestseller list in the German Amazon marketplace in 15 categories.

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