Food & Nutrition

Everything You Need to Know About Keto Diet Fruit

Everything You Need to Know About Keto Diet Fruit

Often referred to as nature's candy, fruit is high in sugar, giving it its signature sweet taste. That's exactly why you'll hear that fruit has no place in low-carb, ketogenic diets. But is this really so or has fruit been unfairly vilified in low-carb communities?
 
Truth is that you do have to be careful with fruit on keto. One medium apple, for example, has at least 21 grams of net carbs. That's pretty close to the average 30 grams net carbs limit that most keto dieters follow. However, there are low-carb exceptions you can enjoy on a keto diet. 
 
To help clear any confusion about the role of fruit in keto diets, read our comprehensive overview below. You will also find a list of the top low-carb fruits to add to your diet and examples of those you need to avoid. We also explain how much keto diet fruits you can eat and offer a couple of recipes to include them into your diet.

Why You Need to Limit Fruit on Keto

The ketogenic (keto) diet is by definition a low-carb, high-fat diet. On this diet, carbs are usually limited to below 50 grams a day which is around 5-10% of your total daily calorie intake. In comparison, the average person eats between 225 and 325 grams of carbohydrates a day on a standard diet.
 
The goal of this drastic carb reduction is to induce a metabolic state called nutritional ketosis. In this state, your liver starts producing great amounts of ketone bodies (aka ketones) which are acidic molecules that replace glucose from carbohydrates as fuel.
 
In order to limit your carb intake to a maximum of 50 grams per day, keto experts recommend eating low-carb fruits and vegetables. This can be a bit tricky as carb content varies between different plant foods, so you need to research your fruits and vegetables carefully.
 
Another thing worth noting is that there are three main types of carbohydrates: starches, sugars, and fiber. Of these three, sugars spike blood glucose levels the most, while fiber has no direct effect whatsoever. Fruit being particularly high in sugar is the most problematic plant food for keto. But if you plan your diet right, fruit can and should be part of your keto journey.

About Fruit and Its Sugars

Botanically speaking, fruit is the seed-bearing structure formed from the ovary of flowering plants. But culinary speaking, fruit is any sweet-tasting part of a plant, especially when it's also coincidentally a botanical fruit. In this article, we'll be talking mainly about fruit in the culinary sense for simplicity’s sake.
 
Fruit gets its sweet taste from sugar. Most of this sugar is a combination of fructose, glucose, and sucrose. Each is metabolized differently, but all are anti-ketogenic and here's why:
 
Fructose– Also called fruit sugar, fructose is a simple monosaccharide that doesn't affect blood sugar whatsoever. However, that doesn’t make it’s harmless. Fructose is entirely metabolized in the liver where it quickly replenishes glycogen and boosts triglyceride synthesis spelling disaster for ketosis [1].
 
  • Glucose– Plants make glucose through photosynthesis using water and carbon dioxide. It's the most common source of energy for most organisms, including plants. When you eat glucose, it circulates the blood stream until it's used as energy or stored as fat. This strongly inhibits ketone synthesis.
  • Sucrose– Sucrose is a disaccharide containing equal parts fructose and glucose. Your body digests sucrose quickly by breaking it down into its constituents (i.e. fructose and glucose). Sucrose also affects blood glucose and glycogen synthesis. Not all fruit contains sucrose, though.
The ratio of these sugars and their density in fruit varies greatly. Some fruit has a fairly low sugar content, making it suitable for the keto diet, but others are almost like snacking on a chocolate bar. That's why you need to know your keto diet fruits well.
 
Besides sugar, fruit is also a source of fiber, vitamins, minerals, and antioxidants. Some fruit also has small amounts of fats and protein. For these, and many other reasons, fruit is considered an important function food that helps maintain good health,[2] even on a keto diet.

Why Eat Keto Diet Fruits?

In case you're wondering why not just remove fruit completely from your keto diet, here are a couple of reasons to make keto diet fruits a part of your lifestyle:
 

1. A Source of Vitamin C

Vitamin C is an important water-soluble vitamin we need for the biosynthesis of collagen, certain proteins, and neurotransmitters. Your brain also heavily relies on vitamin C for antioxidant defense. Adults generally need around 75-120 mg of vitamin C daily to maintain these functions [3]. The problem with vitamin C is that it degrades when exposed to heat and light, so unlike fruit, cooked vegetables are not the best source of this nutrient.
 

2. Rich in Polyphenols

Polyphenols are a special group of phytochemicals – plant components with antioxidant properties. There are thousands of polyphenol compounds in fruits and vegetables, and examples include flavonoids, coumarins, lignans, tannic acid. By including fruit into your keto diet, you can reap some of the many health benefits of polyphenols like a reduced risk of type II diabetes and cardiovascular disease [4].
 

3. A Source of Fiber

Plant foods like fruits are the only natural source of dietary fiber. Fiber is an indigestible type of carb that can be either soluble or insoluble. Both types are essential for normal bowel movements and a balanced gut flora. Many low-carb fruits also happen to be high in both soluble and insoluble fiber.
 

4. For a Touch of Sweetness

You can add sweetness to your smoothies, muffins, and keto desserts by adding keto diet fruits to these meals. Every fruit also has its unique flavor which further enhances the palatability of keto desserts. Just make sure to keep your intake within the recommended daily limits, and you can enjoy fruity keto desserts worry-free.
 

5. A source of Other Essential Nutrients

We already mentioned that fruit is an important source of vitamin C. Well, fruit is also a great way of meeting your daily needs for potassium and folate – two nutrients that studies show most people are not eating enough [5]. You will also find these nutrients in certain vegetables, but fruit is a more reliable source of these nutrients as it is, more often than not, eaten fresh.
 

What Constitutes Keto Diet Fruit?

Keto diet fruit is any fruit with a low carb content. A low carb content would be anything below 10 grams of net carbs per serving of fruit. Below is a list of low-carb, keto diet fruit for you to consider. You'll find their net carb* content per 100 grams of fruit included:
 

Berries (5-12 grams)

Most berries are low-carb. Examples of berries to take on a keto diet include blueberries, strawberries, blackberries, mulberries, boysenberries, gooseberries, currants, and goji berries. Of these, blueberries and currants are highest in carbs. Keep your intake below 100 grams a day to play it safe.

Limes (7,7 grams)

A lime is a hybrid citrus fruit that you’ll find available year-round. Limes are fairly low in sugar as evident by their sour taste. Add them to your keto meals to boost your vitamin C intake and accent flavors of your favorite keto dishes (hello guacamole).

Lemons (6 grams)

Another sour fruit on the list, lemons are also low in sugar but high in vitamin C with one whole lemon providing 140% of the daily value for this important nutrient. Drizzle lemon over grilled fish, add it to your salad dressing, or simply make a keto-friendly lemonade sweetened with stevia.

Rhubarb (2,7 grams)

Although rhubarb is a vegetable, it is culinary fruit. The plant's leaf stalks are the only edible part noted for their tart and slightly sweet taste. Rhubarb complements strawberries well in desserts but there are many other ways to use this low-carb keto diet fruit. Studies show that rhubarb has powerful healing properties with evidence that it can even fight sepsis [6].

Prickly pears (6 grams)

Prickly pears are a type of cactus that produces succulently sweet and refreshing fruit also known as cactus figs. With only 6 grams of net carbs per 100 grams of fruit, there's no reason not to enjoy a prickly pear from time to time. One study found that the antioxidants in prickly pears help prevent DNA damage and diabetes [7].

Starfruit (4 grams)

Also known as carambola, star fruit is an exotic keto diet fruit you can find at Asian supermarkets. You can eat it raw or cook it with savory dishes like teriyaki chicken. Make sure to eat slightly ripened carambola as overripe fruits are higher in sugar content.
 
Other than these fruits, you can also consider coconut, avocados, and olives as keto diet fruits. These may not technically fall under the same category as the fruits above, but they are botanically fruits. What's best about these three is that they're higher in fat content than other fruits and also come with plenty of fiber.
 
Fruit you need to avoid on a keto diet include:
  • Bananas- A medium banana contains almost 30 grams net carbs. These are mostly sugars but some are starches.
  • Apples- Apples are also quite high in sugar.
  • Cherries - Both sweet and sour cherries are equally high in sugar.
  • Melons- Honeydew, cantaloupe, and watermelon are sweet for a reason.
  • Oranges - Oranges and even grapefruit are not allowed on keto.
But in general, if a fruit tastes overwhelmingly sweet, it’s a sign that it’s high in sugar. Avoid all succulent sweet fruits like kiwis, peaches, nectarines, mangoes, grapes, and papayas and stick to low-carb keto diet fruit.
 
Notes:
*Net carbs are total carbs minus fiber. For example, if a serving of fruit has 15 grams total carbs of which 5 grams is fiber, this fruit has a total of 10 grams net carbs. The reason fiber is extracted from the total carb content is because it does not affect blood glucose levels or ketosis.

How Much Keto Diet Fruits Can I Eat?

That really depends on the fruit in question. But generally speaking, we suggest sticking to one serving a day for fruits with a carb content of less than 5 grams per serving. That leaves you plenty of room for low-carb vegetables and the sneaky carbs found in high-fat and protein foods.
 
To make sure you're not going overboard with fruit, it's a good idea to weigh your fruit and check its nutrition facts profile on websites like MyFitnessPal or SELF Nutrition Data. Or simply stick to the fruits listed in this article and you're good to go.
 
To make fruit a part of your keto diet, it's best to add it to your meals instead of eating it on its own. For example, you can make a small fruit salad topped with heavy cream (sweetened with stevia, of course). You can also add a bit of keto diet fruit to your smoothie, chia pudding, keto muffins or top cheesecakes or pancakes with a couple of berries.
 
For more inspiration, visit our Recipes section and read our article covering 7 low-carb, keto diet fruit and offering recipe ideas.

A Couple of Exceptions

As already mentioned, coconuts, avocados, and olives are higher in fat than most other fruit while also being low in carbs. That means you can eat these fruits in greater amounts than other keto diet fruit. Here's a quick nutritional breakdown of these three:
 

Coconut

A 100 grams of raw coconut meat provides only 5 grams of net carbs. On the other hand, the same amount provides 7,2 grams of dietary fiber, 27 grams of fat, and 2,7 grams of protein. Coconut is also an excellent source of manganese, selenium, and iron.
 

Avocado

A 100 grams of raw avocado comes with only 1,8 grams of net carbs and as much as 14,7 grams of fat. Most of this fat is monounsaturated (MUFA), which reduce risk of cardiovascular diseases and other inflammation-related diseases [8]. Besides that, avocado is rich in vitamins C, E, K, B6, and folate. Avocado is also a good source of potassium, which is a mineral that most of us need to get more of.
 

Olives

A 100 grams of ripe olives provides 3 grams of net carbs and 10 grams of fat. Olives are also a good source of iron and copper. Olives are also rich in phenols, which are bioactive plant compounds that studies show provide antioxidant protection [9].
 
As you can see, these three foods contain more fats than they do protein, making them ideal for your keto diet. Feel free to enjoy these three keto diet fruits but keeping their carb content in mind. They may not be as sweet as most other fruit, though and when it comes to olives specifically, they suit only savory dishes.

What Will Happen if I Eat Too Much?

If you eat several servings of keto diet fruit in a single day, chances are you'll be well beyond your 50 grams a day mark. This will increase your blood glucose levels to the extent that ketosis will be inhibited and glycogen stores replenished.
 
Although this isn't a catastrophe or any reason for concern, you did sabotage your keto diet. Ketosis is the goal of this diet and for it to work, your ketone levels need to remain relatively high (0.5-3.0 mmol/L).
 
For this to happen, your blood glucose levels need to be at a constant low. This is only possible when you eat fewer than 50 grams of total carbs per day or 30 grams of net carbs per day. Breaking your carb fast by overeating on fruit means you'll need to start all over again.
 
However, there are ways to get your body back into ketosis quickly:
 

1. Exogenous Ketones

These are dietary supplements containing ketones made in the laboratory. The have the exact same chemical formula as endogenous ketones (made inside your body). The only difference is that exogenous ketones are bound to minerals or alcohols to aid in their absorption.
 
A fairly recent study involving 15 participants found that drinks containing exogenous ketones lowered blood glucose, free fatty acid and triglyceride levels in all subjects [10]. The same study also found that ketone drinks containing β-Hydroxybutyrate (a ketone body) elevates blood ketone levels for over 8 hours.
 

2. Exercising

Vigorous exercising depletes muscle and liver glycogen [11]. However, keep in mind that it takes a lot of energy for this to happen. Some people even do extreme types of "glycogen depletion workouts" for this purpose. Weight lifting, and high-intensity intermittent training are good examples of glycogen-depleting workouts. If you can handle this type of activity, then do give it a go.
 

3. Fasting

Fasting also helps you reach ketosis quicker. You can go for short, half day fasts or a whole day fast to deplete liver glycogen, lower blood glucose levels, and increase ketone production. In case you're wondering how exactly you can use fasting to get into ketosis, read our article here.
 
Make sure to break your fasts with low-carb and high-fat meals to boost ketone production. And if you're considering combining exercising with fasting, keep in mind that this could negatively affect your muscle mass. It's best to stick to just one method to help correct ketosis mishaps for safety reasons.
 

4. Taking MCT oil

MCT stands for medium-chain triglycerides. These are unique types of saturated fats that studies show your body can easily turn into ketones [12]. MCT oil is a supplement that is a purified source of these fats. Because MCTs don't require bile and enzymes for digestion, they get easily absorbed in your small intestine and they reach the liver quickly where they're turned into ketones.

Can I Simply Do Without Fruit?

The keto diet already excludes a range of foods most people eat on a daily. Examples include grains, legumes, honey, and refined sugar. Studies proved that this approach was completely safe, and even beneficial for overall health and long-term weight loss [13].
 
Most of these studies followed subjects who ate a standard keto diet that also included fruit on the daily menu. So, there's no guarantee that excluding this food group as well is safe. That's why we recommend eating a small portion of fruit on your keto diet.
 
Still, if you feel like you can get all the vitamin C, fiber, and other nutrients from keto-friendly vegetables, nuts, and seeds, then it's up to you to decide. After all, the classification of plant foods into fruits and vegetables as we know it is only a culinary thing based on taste.
 
To explain this further consider zucchini, tomatoes, eggplants, and cucumbers. These are all botanical fruits. The only reason they're not consider a culinary fruit is because they lack sweetness. So, all in all, as long as you're eating a variety of plant foods on keto, you should have no reason for concern.

How to Store and Buy Keto Diet Fruit?

Keto diet fruits make up only a small portion of your overall diet. That means that you'll be eating them occasionally and in small amounts. Buying small portions of fruit daily can be time consuming while larger batches are likely to spoil on a keto diet. So, what's a keto dieter to due when it comes to fruit storage and buying?
 
We suggest buying a combination of frozen and fresh fruits for practicality and frugality reasons. Frozen fruit tends to be a whole lot cheaper than their fresh counterparts. Just make sure to consume your frozen fruit within 3 months as prolonged storage tends to degrade vitamins and antioxidants in fruit [14].  
 
If you're thinking of making dried fruit a part of your keto diet, think again. Dried fruit, even if it's dried berries is higher in carb content than fresh fruit. Fruit juices are also higher in carbs than whole fruits due to a loss of fiber.
 
And to keep your countertop fruit fresh for longer, there are a couple of tricks that help:
 

1. Store fruit away from vegetables 

When fruit is stored near vegetables, it tends to go bad faster.
 

2. Move to fridge if you notice fruit going bad 

Preferably in the drawer of your refrigerator to reduce oxygen exposure as oxygen causes fruit to degrade faster.
 
3. Keep fruit in a zip-lock bag 
This is another way to prevent fruit from oxidizing. Just make sure that you place sealed fruit in a cool, dry place as well. This prevents "sweating" inside the bag.

Takeaways

Fruit has its place in a keto diet, albeit a tiny one. It's often higher in sugar than other plant foods, so caution is necessary when eating fruit on a keto diet. Luckily, there are plenty of low-carb keto diet fruits out there for you to choose from.
 
Adding keto diet fruits to your regimen helps you spice up your keto desserts, add important vitamins to your daily meals, and boost your intake of health-protecting antioxidants.
 
When choosing keto diet fruits, go for those that have a net carb content of 5 grams per serving or lower. Keep your intake to one serving a day and make sure to keep an eye on your daily carb intake when eating keto diet fruit.
 
And if you think that excluding fruit from your diet completely can make your life easier, then consider adding more low-carb botanical fruit to your regimen. This way, you'll ensure you're not missing out on the nutrients and antioxidants typically found in fruit while also meeting your minimal daily need for carbs and also dietary fiber.

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