The ketogenic diet is when people change their nutrition plan, so their bodies produce ketones. This occurs in a process called ketosis, which is when a person burns fat instead of carbohydrates as their main source of energy.

The ketogenic diet is low in carbohydrates and higher in fats. While several versions of the diet exist, a person will typically eat 3 to 4 grams (g) of fat for every 1 g of protein and carbohydrates.

The result is a diet that provides around 70% of calories from fat, 20% from protein, and 10% from carbohydrates. This is different from a traditional low-carbohydrate diet that usually involves increasing protein intake.

The Mediterranean ketogenic diet is one example of a ketogenic diet that is high in fat. It incorporates no more than 30 g of carbohydrates, 1 g of protein for every 2.2 pounds of bodyweight mainly coming from fish, and fat sources that are 20 percent saturated fat and 80 percent unsaturated fat, primarily from olive oil.

In this article, we look at the best foods to eat for people who are following a ketogenic diet. We also examine what should be avoided and what are the benefits and risks.

Fats


Fats are the biggest source of energy and calories in a ketogenic diet.

Not all fats are the same. For example, doctors do not consider trans fats to be healthful fats. These are hydrogenated fats added to foods to maintain their shelf life.

Trans fats increase a person’s cholesterol levels and increase inflammation in the body. A person should avoid trans fats on a ketogenic diet.

Saturated fats are a significant part of the ketogenic diet. Saturated fats are those that are solid at room temperature. The body needs some of these to promote a healthy immune system and for other body functions.

Ketogenic-friendly saturated fat sources include:

  • coconut oil (0 g carbohydrate per 100 g)
  • grass-fed beef (0 g carbohydrate per 100 g)
  • butter from grass-fed cows (0 g carbohydrate per 100 g)
  • whole milk and whole-milk dairy foods (4.88 g carbohydrate per 100 g)

Dietitians and doctors call monounsaturated and polyunsaturated fats the “good” fats.

Research shows keto diets with a higher proportion of unsaturated fats versus saturated fats have long-term benefits. These fats are liquid at room temperature, and sources of them include:

  • almond oil (0 g carbohydrate per 100 g) 
  • flaxseed oil (0.39 g carbohydrate per 100 g) 
  • mackerel (0 g of carbohydrate per 100 g) 
  • olive oil (0 g of carbohydrate per 100 g) 
  • sardines (0 g of carbohydrate per 100 g) 
  • pumpkin seeds (8.96 g of carbohydrate per 50 seeds) 
  • sustainably-harvested seafood walnuts (13.71 g of carbohydrate per 100 g) 
  • wild salmon (0 g of carbohydrate per 100 g)

Proteins

The ketogenic diet is not a high-protein diet. The body converts excess protein to glucose when carbohydrate intake is low, thereby restricting ketosis.

Foods that are sources of protein on the ketogenic diet tend to be the same foods that provide healthy fats.

For example, grass-fed meat products are a staple on this diet. Grass-fed meats tend to have higher levels of omega-3 fatty acids than others, which is an advantage on the ketogenic diet.

Nuts, seeds, and eggs are also ketogenic diet staples.

Seafood, especially fish and low-carbohydrate shellfish, such as shrimp and most crabs, are also on the menu.

Some shellfish also contain carbohydrates, which people on a ketogenic diet should take this into account when eating these options. These varieties include clams, mussels, oysters, and squid.

Vegetables

Ketogenic-recommended vegetables are of the non-starchy variety. “Starchy” vegetables contain carbohydrates and are not a part of the ketogenic diet.

Examples of non-starchy vegetables include:

  • artichoke (10.51 g of carbohydrate per 100 g) 
  • asparagus (3.88 g of carbohydrate per 100 g) 
  • baby corn (18.7 g of carbohydrate per 100 g) 
  • broccoli (6.64 g of carbohydrate per 100 g) 
  • Brussels sprouts (8.95 g of carbohydrate per 100 g) 
  • eggplant (5.88 g of carbohydrate per 100 g) 
  • green beans (6.97 g of carbohydrate per 100 g) 
  • okra (7.45 g of carbohyrdrate per 100 g) 
  • onions (9.34 g of carbohydrate per 100 g) 
  • salad greens, such as romaine, spinach, arugula, and endive squash (11.69 g of carbohydrate per 100 g) tomato (3.89 g of carbohydrate per 100 g) 
  • turnips (3.39 g of carbohydrate per 100 g) 
  • water chestnuts (6.34 g of carbohydrate per 100 g)

Fruits

Fruits are not a part of the ketogenic diet because of their higher carbohydrate and sugar content.

However, avocado is a part of the diet thanks to its high-fat content. Blackberries are also sometimes included due to their very high fiber content.

Foods to avoid

Foods that are mainly carbohydrates, such as breads and pastas, are not seen on the ketogenic diet. 

Most fruit is not ketogenic-diet friendly either, as mentioned above.