If you’re a fruit lover who’s on the ketogenic diet, you may be wondering if you can sneak some fruit into your keto meal plan without affecting weight loss or your other keto goals. Fruit is healthy, after all, right?
But on a high-fat, low-carb diet, eating too many net carbs can elevate your blood sugar and kick you out of ketosis.
Luckily, there is a difference between high-carb fruits and low carb fruits — and there are some keto-friendly fruits that even have healthy fats. In this article, you’ll learn how to incorporate “nature’s candy” into your meal plan without harming your insulin sensitivity or blood sugar levels.
A Short History of Fruit
You know all the most popular fruits of today. Sweet bananas, strawberries, and apples, juicy oranges and tangy berries.
Fruits started in the wild where they were consumed by humans and animals, then cultivated in more agricultural settings. Today, it’s almost impossible to find fruit in the wild — at least in the U.S, — except for some wild berry bushes and a citrus tree here and there.
Human beings have a long tradition of gathering, cultivating, and eating fruits. To understand why people like fruit and what the effects of fruit are on human health, it is vital to understand the history, science, and biology behind human fruit intake.
Ancient and Modern Fruit
Humans and animals are naturally attracted to fruit because it contains sugar, vitamins, minerals, phytonutrients, and antioxidants.
Fruit plants evolved alongside animals, using their sweetness and nutritional value to hitch a ride for their seeds in the digestive systems of mammals (including humans) and birds. This relationship allowed fruit plants to expand their range.
Somewhere around 10,000 years ago, as humans made the shift from nomadic hunting and gathering to agriculture, they began selectively breeding fruit for traits they enjoyed or preferred.
As a result, over hundreds and eventually thousands of years, fruits became bigger, juicier, easier to grow and eat, and — of course — sweeter.
Most modern fruits grown by humans have followed this path from wild to domesticated. As a result, most modern fruits are almost unrecognizable compared to their ancient counterparts.
In addition to getting bigger, easier to eat, and sweeter, this process of cultivation may have also reduced the number of phytonutrients in modern plants. While modern fruits are easier to grow, they may be less nutritious than ancient or wild plants.
Higher Yields Equal Fewer Nutrients
Recent humans have continued the trend with modern agriculture. Post World War II fruit production has intensified, becoming more industrialized and technological. Big corporations focus on high output and fast growth rates, which reduces the levels of vitamins and minerals in food[*].
As companies focus on increased sugar content and high yield to make more money[*], greenhouse gas emissions resulting in higher carbon dioxide levels are also accelerating the growth of plants and increasing their carbohydrate content[*][*][*].
One paper published in 2008 found higher yields of fruit and other plants meant lower levels of nutrients: high yield crops had 5-40% fewer vitamins, minerals, and proteins[*].
Another researcher found in 1991 that compared to organic methods, non-organic plant foods had 30% lower levels of the following vitamins and minerals: calcium, copper, iron, magnesium, manganese, phosphorus, potassium, sodium, zinc, beta-carotene, and ascorbic acid[*].
Organic fruits are higher in antioxidants, with less pesticide residue and less of the heavy metal cadmium[*].
Is Fruit Really That High in Sugar?
Sucrose, glucose, and fructose are carbohydrates. Glucose and fructose are both called simple sugars because they each have one sugar molecule.
Most fruits contain sucrose. Sucrose is made up of a combination of glucose and fructose.
Carbohydrates are a fast-acting, readily available form of energy. But fructose is different from other carbs in a significant way: your liver must convert fructose into glucose before your body can use it for fuel.
Fructose and Your Health
Fructose doesn’t raise insulin levels as much as other sugars, but it can still cause problems. Fructose is less filling than other sugars and causes more fat storage[*].
Other issues associated with fructose include increasing[*]:
- Small dense LDL levels — the type of cholesterol that causes health problems
- Fat storage in your liver
- Triglyceride production
- Free radicals and oxidative stress
Eating fructose is also linked to obesity, type 2 diabetes, heart disease, metabolic syndrome, insulin resistance, and high blood pressure[*].
Because of its effects on your liver, fructose has similar side effects to ethanol (drinking alcohol) compared to other forms of sugar.
Fructose doesn’t get you drunk, but drinking a can of soda — or binging on fruit — can have a similar effect on your liver to drinking a can of beer[*].
Is Sugar Addictive?
All sugar, even natural sugar from fruit, is addictive to animals and people.
In ancient times, sugar did not cause as many problems as it does now, because it was only available in the form of fruits growing in late summer and early fall.
People 10,000 years ago didn’t eat fruit or artificial processed sugar foods daily or year-round.
In modern humans, sugar can trigger the brain’s opioid reward system. Some scientists think eating sugar has parallels with drug abuse[*].
Fructose and Keto
If carbs and sugar are a no-no on keto, that’s doubly true for fructose because of its ability to cause additional health problems.
Fructose is also anti-ketogenic because your liver has to metabolize it. As soon as your body digests fructose, your liver glycogen stores are replenished, taking you out of ketosis temporarily.
But I Thought Fruit Was Necessary?
It’s true — some fruits contain a good amount of vitamins and minerals, but that doesn’t make them a healthy part of a low-carb or keto diet.
Dr. Jennifer Di Noia, of William Patterson University in New Jersey, studied 47 plant foods and ranked the top 41 “powerhouse fruits and vegetables” from highest to lowest based on the content of 17 critical nutrients: fiber, potassium, protein, calcium, folate, vitamin B12, vitamin A, vitamin D, and others[*].
Here’s the top 10 list:
- Chinese cabbage
- Beet greens
- Leaf lettuce
- Romaine lettuce
- Collard green
What’s missing? You may have noticed fruit is absent from the top ten most nutritious plant foods!
The four most nutritious fruits in the study were bell pepper (#17), pumpkin (#20), tomato (#27), and lemon (#28). Only ten of the 41 powerhouse fruits and vegetables were actually fruits.
You’ll notice that the fruits that were included are very low-carb.
Many fruits are nutritious, but most fruits have a relatively high carb content. If you want a daily source of vitamins and minerals, start with eating more low-carb vegetables.
Top 12 Fruits To Eat On A Keto Diet
Too much fructose is bad for your health, but not all fruits are high in fructose. Some fruits are lower in sugars and pack a big nutritional punch.
In moderation, the health benefits of certain fruits can outweigh the downsides of sugar and fructose. And all fruits are far better than processed foods for an occasional treat.
Here are the top 12 fruits that fit into a keto diet perfectly:
Lemon wedges or lemon juice are delicious in water or other beverages. Lemon is a good source of ascorbic acid (natural vitamin C), aids digestion, prevents kidney stones, and even freshens your breath.
Per 100 grams, lemons contain 29 calories, 2.8g fiber, 6g net carbs, and 1.1g fructose. A typical lemon serving size is 1 tablespoon (15g).
Limes are another popular citrus fruit. High in potassium and magnesium, limes can improve digestion, fight off infections, help lower your blood sugar, reduce the chance of cancer and heart disease, improve heart health, and reduce inflammation.
Per 100 grams, limes contain 30 calories, 2.8g fiber, 8.5g net carbs, and 0.6g fructose. A typical lime serving size is 1 tablespoon (15g).
Avocados are a fruit, not a vegetable. They contain more potassium than bananas and they’re loaded with healthy fats, fiber, and phytonutrients like beta-sitosterol, lutein, and zeaxanthin.
Avocados are one fruit that fits right into a keto diet thanks to the high-fat content.
Per 100 grams, avocados contain 167 calories, 15g fat, 6.8g fiber, 1.8g net carbs, and just 0.08g fructose. A standard avocado serving size is 1/3 of an avocado or about 50 grams. However, you can easily eat more avocado than that on your keto diet.
#4: Olives (Green or Black)
Just like avocados, most people don’t think of olives as fruits. Olives are a good source of dietary antioxidants, and healthy fats.
They can improve circulation and reduce blood pressure by increasing nitric oxide levels. Olives are also anti-inflammatory, and their vitamin E content boosts brain health and helps keep free radicals under control.
Per 100 grams, olives contain 81 calories, 6.9g fat, 2.5g fiber, 3.1g net carbs, and 0g fructose. A typical olive serving size is two jumbo olives, or about an ounce (28.5g).
#5: Bell Peppers
In Dr. Di Noia’s powerhouse fruits and veggies study, bell peppers were the #1 ranked healthy fruit, ranked #17 overall[*].
You can eat them like vegetables — raw or cooked. Bell peppers are filling, low in calories, and great for keto-friendly dipping sauces.
This fruit is extremely rich in vitamins like vitamin C and carotenoids, and a great source of antioxidants. Eating bell peppers is associated with health benefits like improved eye health and reduced risk of chronic diseases like heart disease and cancer.
Per 100 grams, bell peppers contain 20 calories, 1.7g fiber, 2.9g carbs, and 1.12g fructose. A typical bell pepper serving is 1 cup chopped (150g).
Tomatoes are yet another fruit you can enjoy like a vegetable. You can eat them raw, steamed, sauteed, or as part of a sauce, soup, or stew. Cherry or grape tomatoes are perfect for snacking.
Tomatoes are loaded with the antioxidant lycopene, which reduces the risk of heart disease and cancer. Tomatoes also provide plenty of vitamin C, potassium, folate, and vitamin K.
Per 100 grams, tomatoes contain 18 calories, 1.2g fiber, 2.7g carbs, and 1.37g fructose. A typical tomato serving is 1 cup, chopped or sliced (150g), or 10 cherry tomatoes (170g).
Once dismissed by fat-phobic dietitians, coconuts are an outstanding choice for your keto meal planning.
They’re considered a fruit, a nut, or a seed depending on who you ask — but coconuts are great for you no matter how you classify them. To avoid fructose, stick with the fleshy interior instead of drinking coconut water.
Coconuts are packed with natural dietary fiber to help satisfy your appetite. They also provide vitamin B6, iron, magnesium, potassium, zinc, copper, and selenium. And coconuts are loaded with healthy fats, including lauric acid, which increases your HDL or “good” cholesterol.
Per 100 grams, coconut flesh contains 354 calories, 33g fat, 9g fiber, 6g carbohydrates. A typical serving of coconut meat is 1/3 cup (about 28.5g).
No one is going to mistake strawberries for a vegetable. Strawberries are a healthy fruit that can safely satisfy your fruit cravings on keto (in moderation).
Pro tip: whip up some fresh whipped cream and add to fresh berries for a simple, low-sugar dessert.
Strawberries have plenty of fiber, high levels of polyphenols, and they’re a good source of manganese and potassium. When it comes to antioxidant capacity, strawberries are among the best of the best fruits.
Per 100 grams, strawberries contain 32 calories, 2g fiber, 5.7g carbohydrates, and just 2.44g fructose. A typical serving of strawberries is 8 large strawberries (about 144g).
Raspberries offer plenty of antioxidants: vitamin C, quercetin, and gallic acid. This fruit can help prevent cancer, heart disease, and circulatory problems.
They also contain ellagic acid, a natural compound with additional chemopreventive (cancer-preventing) benefits and anti-inflammatory properties.
Per 100 grams, raspberries contain 52 calories, 6.5g fiber, 5.5g carbohydrates, and a mere 2.35g fructose. A typical serving of raspberries is 1 cup of raspberries (about 123g).
Blackberries are a bramble fruit that grows in upright shrubs or trailing varieties. Unripened blackberries are incredibly tart, while the ripe berries are dark, dull, soft, and very sweet-tasting.
Blackberries are high in vitamin C: a cup of blackberries has half the U.S. daily recommended value of vitamin C for an adult on a 2000 calorie diet.
They’re also high in fiber, vitamin K, and manganese. Blackberries even help reduce inflammation, boost immune function, and fight cancer with abundant antioxidants.
Per 100 grams, blackberries contain 43 calories, 5.3g fiber, 4.3g carbohydrates, and 2.4g fructose. A typical serving of blackberries is 1 cup of fresh blackberries (about 142g).
Plums are a pit fruit that can range from sweet to tart. You can eat plums fresh or use them for making jam or other fruity desserts.
Plums contain vitamins A, C, and K, along with potassium, copper, and manganese.
They’re also rich in antioxidants that can reduce inflammation and protect your cells from oxidative damages. Plums contain about twice the amount of polyphenols compared to most other fruits.
Per 100 grams, plums contain 46 calories, 1.1g fiber, 9.5g carbohydrates, and 3g fructose. A typical serving of plums is 2 small plums (about 131g).
Blueberries are relatively low in calories but packed with vitamin C, vitamin K, and manganese. They contain trace amounts of many other nutrients.
Blueberries rank higher than most fruits for antioxidant content. They’re also high in beneficial flavonoids — colorful polyphenol antioxidant compounds — like anthocyanins.
The Spectrum of Fruits on a Keto Diet
Now that you know the best fruits to eat on a keto diet, where do all the rest fit?
The good news is that you can eat any fruit in moderation on keto. Since most fruits do contain carbohydrates, the key to success is knowing how many total carbs you can eat on a keto diet.
If you decide to eat fruit, stick to fresh, raw or home-cooked fruits. Avoid fruit juices (other than lemon or lime juice) and fruits with added sugar, juice, or other processed or packaged forms of fruit.
Here’s how most other fruits rank from best to worst for keto eating. Consume the lower-ranked fruits occasionally and in limited quantities, not daily:
Can You Eat Fruit on a Keto Diet?
In a word, yes. You can eat fruit on the keto diet. Think of fruits more like a condiment or seasoning, as opposed to a main course or frequent snack.
For example, fruit can be a perfect addition to salads for more color and flavor, or you can make sugar-free, low-carb jams and preserves.
You can enjoy fruits by themselves or try them in these awesome PerfectKeto recipes and smoothies:
- Citrus Keto Green Smoothie
- Buzzy Raspberry Lemonade Spritzer
- Raspberry Keto Thumbprint Cookies
- Blueberry Cheesecake Pancakes
- Nootropic Berry Chocolate Protein Smoothie
- Chocolate Pancakes With Blueberry Butter
The bottom line: don’t stress out if you feel like indulging your sweet tooth with fruits.
Fruits offer much better nutritional value than processed carb sources, and in moderation they won’t have much negative impact on fat burning or fat loss.