“Is this keto-friendly?”
“Can I eat this on keto?”
Questions like these are asked on keto diet forums and Facebook groups multiple times a day without a definitive answer. The line between what we should eat and avoid to sustain ketosis gets blurred after we cut out the obvious high-carb foods.
To truly figure out what is keto-friendly and what we shouldn’t eat on keto, we must have: general understanding of foods that are keto-friendly and foods that will almost always kick us out of ketosis and the ability to apply the principles behind what makes a food bad or good for ketosis so you know how to figure out if a questionable food is keto-friendly for you.
By the end of this post, we will cover all of these bases so that you will be able to answer the question “can I eat this on keto?” or “is this keto-friendly?” for virtually any food, beverage, or ingredient that you find.
Let’s start by developing a general understanding of what it means to follow the keto diet and how this translates to keto-friendly foods and foods that we should avoid.
Are You Following the Ketogenic Diet Correctly?
The Keto diet is one of the only popular diets that provide us with a precise way to tell if you are implementing it properly. Are you in ketosis consistently (I.e., when your blood ketone levels are 0.5 mmol/L or higher) or not?
If you answer yes to this question, then you are technically on the keto diet.
If the answer is no, then you are on a low carb diet and most likely need to eat fewer carbs until you can achieve and sustain ketosis.
Although other variables matter much more than how many ketones you are producing, including your overall health and weight loss results, to experience all the benefits of the keto diet you must be in nutritional ketosis.
The primary variable that separates you from nutritional ketosis? The food you eat.
What Should You Eat on Keto? Foods to Avoid vs. Keto-Friendly Foods
In general, here is what you should and shouldn’t eat on the keto diet:
Avoid These Foods to Enter and Sustain Ketosis
- Grains and grain-based foods – wheat, corn, rice, pasta, granola, cereal, etc.
- Sugar and sugar-sweetened products – table sugar, soda, sports drinks, honey, agave, maple syrup, etc.
- Most fruits – apples, bananas, oranges, etc.
- Tubers and tuber-based food products – potatoes, potato chips, French fries, yams, etc.
- Meats – fish, beef, lamb, poultry, eggs, etc.
- Low-carb vegetables – spinach, kale, broccoli, and other low carb veggies >
- High-fat dairy – hard cheeses, high fat cream, butter, etc.
- Nuts and seeds – macadamias, walnuts, sunflower seeds, etc.
- Avocado and berries – raspberries, blackberries, and other low carb fruits >
- Sweeteners – stevia, erythritol, monk fruit, and other low-carb sweeteners >
- Other healthy fats – coconut oil, avocado oil, olive oil, animal fats, etc.
This simple food list may be all you need as guidance to help you enter and maintain ketosis. The key principle that separates the foods we should eat from the foods we should avoid on keto is how many carbs each food typically contains.
Most grains, for example, contain enough carbs per cup to prevent you from producing ketones or swiftly kick you out of ketosis. The same concept applies to sugars, tubers, most fruits, and most of the products that contain these foods/ingredients. Each food is so carb-rich that it can rapidly increase blood sugar and insulin levels, shifting your body from burning fat and ketones to prioritizing sugar use.
In contrast, the keto-friendly foods on the list tend to be so low in carbs and high in fat that your body will burn more fat and ketones when you get almost all of your calories from these foods. Although some keto foods do contain net carbs (e.g., low-carb berries, nuts, seeds, and high-fat dairy), their carb content is not high enough to prevent ketosis when they are eaten in reasonable amounts.
One Key Difference Between Foods You Should Avoid and Keto-Friendly Foods: Net Carb Content
What do I mean by “net carbs”? Technically, it is a term we use to decipher the amount of carbs that our bodies can fully absorb from the grams of dietary fiber that a particular food contains. Many countries, such as the United States and Canada, include dietary fiber in with the total carb count on food labels.
Since fiber isn’t absorbed and used in the same way that net carbs are (i.e., they won’t impair ketosis), we must subtract total fiber content from total carbs to figure out how many carbs are in the food that will decrease ketone production. (If you live in Europe, Australia, or Oceania, the “Carbohydrates” on your food labels already reflect the food’s net carb content, so you won’t have to do any calculations.)
In other words, a keto-friendly food is a food that is low in net carbs (which is the amount of total carbs minus total fiber for those who do not live in Europe, Australia, or Oceania).
Let’s take vegetables for example. Why aren’t all vegetables keto-friendly?
Although vegetables are a healthy part of the diet, this doesn’t mean that each one is also keto-friendly. (Healthy does not always mean keto-friendly and keto-friendly does not always means healthy.)
If we compare kale (a leafy green vegetable) to a sweet potato (a starchy tuber), we will find that one cup of chopped kale only has ~5 grams of net carbs (6.7 g of total carbs minus 1.3 grams of dietary fiber) while one cup of cubed sweet potato has roughly 22 grams of net carbs (4 grams of fiber subtracted from 26 grams of total carbs). This striking difference gains further significance when we look at it from the context of a keto diet as a whole.
For most of us, limiting net carbs to below 25 grams per day for about a week is what we need to do to enter a deep ketosis. If we were to increase our daily net carb consumption above 25 grams, we would make it more and more difficult to sustain deeper levels of ketosis. Once we consume more than 50 grams of net carbs per day, it will be nearly impossible for most of us to sustain ketosis (unless you are very active).
If you take a look at our vegetable example from before, you can now see why starchy tubers aren’t keto-friendly. Although eating a starchy tuber won’t doom you to sugar-burning oblivion, eating a sweet potato instead of kale will make it much more difficult for you to achieve and sustain ketosis (assuming you are eating enough fat and protein).
With that being said, the difference between a keto-friendly food and a food we should avoid on keto does have some gray areas. With due diligence, it is possible to fit some higher carb foods into your diet without kicking you out of ketosis.
How to Determine If a Food is Keto-Friendly for You
One of the most important parts of the keto diet is personalizing it to your lifestyle, goals, and preferences. When we are able to adjust our diets to fit these aspects of our lives, it makes it so much easier to achieve and maintain the results we want.
To make the keto diet easier to follow, we must choose foods that are accessible and enjoyable, foods that make it is easy for us to meet our fat and protein needs while keeping net carbs low. When you consider the foods you eat from this perspective, it makes it easier for you to figure out what is “keto-friendly” for your diet.
On a practical level, here is a step by step process you can use to figure out if you can fit a specific food or product into your keto diet:
- Follow a standard keto diet for a few weeks to get a baseline of how low I need to keep my carbs to sustain ketosis (for most people, this is below 25 grams of net carbs).
- Gather relevant info (i.e., fat, protein, fiber, and net carb content) about the food product in question.
- Figure out what you need to cut out or add in to fit the new food into your diet. What adjustments should you make to stay below the carb limit that tends to keep you in ketosis?
- If the food is high enough in net carbs that you cannot stay within your carb limit, then it is not keto-friendly and you should avoid it. If you can fit the food into your keto diet while meeting your other nutritional needs (i.e., fat, protein, vitamins, minerals, and fiber), then that food is keto-friendly for you.
In general, foods that have around 10 grams of net carbs or more will be much more difficult to fit into your keto diet. This is why any food with more than 6 grams of net carbs per serving will typically find itself on the “do not eat” or “eat in moderation” list for a standard keto diet.
Net carb content, however, is not the only factor we should consider when picking keto foods. Sustaining ketosis and optimal health does not solely rely on carb intake. We must eat the right amounts of protein and fat from high-quality foods as well.
Based on what we learned so far, we could technically classify a teaspoon or two or even three of sugar as keto-friendly because one teaspoon only has ~4 grams of net carbs.
Although this silly dietary approach could technically be used to get us into ketosis, it would be virtually impossible to also consume enough vitamins, minerals, fiber, protein, and fat to sustain a healthy keto diet for a long period of time. This is why we must consider our net carb consumption in the context of our fat and protein intake and the quality of the foods we eat to ensure that we are healthy and happy in the long run.