The ketogenic diet, commonly known as the keto diet, is characterized by its high-fat, moderate-protein, and very low-carbohydrate composition. This dietary approach drastically reduces carbohydrate intake, typically to just 5% to 10% of total daily calories. This reduction forces the body into a metabolic state called ketosis.
During ketosis, the body shifts its primary fuel source from carbohydrates to fat. The liver breaks down stored fat into molecules called ketones, which are then used for energy. This process occurs because the body no longer has sufficient glucose (sugar) from carbohydrates for fuel. Initially used clinically to manage epilepsy in children by reducing seizures, the keto diet has gained popularity for various other potential health benefits.
“The keto diet is now being explored for its potential in managing neurological conditions, cancer, diabetes, PCOS (polycystic ovary syndrome), obesity, high cholesterol, and cardiovascular disease,” notes Emily Stone, M.S., RD, founder of Eat to Enjoy. Many individuals also adopt the keto diet as a weight loss strategy.
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Navigating the ketogenic diet can be confusing, especially when determining which foods are appropriate. While the core principle is low-carb, high-fat, and moderate-protein, understanding the specifics of food choices is crucial for success. This guide provides a clear breakdown of foods to enjoy, limit, and consume in moderation on a ketogenic diet.
Foods You Can Eat on the Ketogenic Diet
When following a ketogenic diet, your food choices should primarily consist of low-carbohydrate options. Here’s a detailed list of keto-friendly foods to incorporate into your meal plan.
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- Fish and Seafood
- Low-carb vegetables
- Cheese
- Avocados
- Poultry
- Eggs
- Nuts, seeds, and healthy oils
- Plain Greek yogurt and cottage cheese
- Berries
- Unsweetened coffee and tea
- Dark chocolate and cocoa powder
Fish and Seafood
Fish and seafood are excellent additions to a ketogenic diet. They are naturally carb-free and rich in protein, B vitamins, potassium, and selenium. Fatty fish varieties like salmon, sardines, mackerel, and albacore tuna are particularly beneficial due to their high omega-3 fatty acid content. Omega-3s are known to improve hemoglobin A1c levels, a key marker for long-term blood sugar control. Regular fish consumption is also associated with a reduced risk of chronic diseases and improved mental well-being. Aim for at least two 3-ounce servings of fatty fish each week.
Low-Carb Vegetables
Non-starchy vegetables are nutritional powerhouses on a keto diet. They are low in both calories and carbohydrates while being packed with essential nutrients like vitamin C and various minerals. These vegetables are also rich in antioxidants, which combat cell damage from free radicals. Focus on non-starchy vegetables with less than 8 grams of net carbs per cup. Net carbs are calculated by subtracting fiber from total carbohydrates. Excellent choices include broccoli, cauliflower, green beans, bell peppers, zucchini, and spinach.
Cheese
Cheese is a keto-friendly staple, boasting zero carbohydrates and a high fat content. It’s also a good source of protein and calcium. However, it’s important to be mindful of saturated fat intake. A 1-ounce slice of Cheddar cheese contains approximately 5 grams of saturated fat. The American Heart Association recommends limiting saturated fat to minimize heart disease risk.
Plain Greek Yogurt and Cottage Cheese
Plain Greek yogurt and cottage cheese are protein-rich and calcium-rich dairy options suitable for keto in moderation. A 7-ounce serving of plain Greek yogurt provides around 8 grams of carbohydrates and 20 grams of protein. Cottage cheese (8 ounces) contains slightly over 6 grams of carbohydrates and a substantial 28 grams of protein. Increasing protein intake can help manage appetite by reducing hunger hormones, promoting satiety. Opting for full-fat versions of yogurt and cottage cheese aligns well with the ketogenic diet’s high-fat requirements and contributes to longer-lasting fullness.
Avocados
Avocados are a fantastic source of heart-healthy fats, particularly monounsaturated fats. They are also rich in potassium, a mineral often lacking in American diets. Half of a medium avocado contains approximately 6 grams of total carbohydrates, with 4.5 grams being fiber, and 360 milligrams of potassium (about 8% of the daily recommended intake). Replacing animal fats with plant-based fats like those found in avocados can contribute to a reduced risk of cardiovascular disease and type 2 diabetes.
Meat and Poultry
Meat is a cornerstone of the ketogenic diet, providing lean protein and containing zero carbohydrates. Fresh meat and poultry are also rich in B vitamins and minerals like potassium, selenium, and zinc. While processed meats like bacon and sausage are technically allowed on keto, they are not the healthiest choices for your heart and may increase the risk of certain cancers. It is recommended to prioritize chicken, fish, and beef, and limit processed meat consumption.
Eggs
Eggs are nutritional powerhouses, packed with protein, B vitamins, minerals, and antioxidants. Two large eggs contain zero carbohydrates and over 12 grams of protein. Eggs promote feelings of fullness and contain antioxidants like lutein and zeaxanthin, which are beneficial for eye health.
Nuts, Seeds, and Healthy Oils
Nuts and seeds are excellent sources of healthy polyunsaturated and monounsaturated fats, fiber, and protein. They are also very low in net carbs. Olive oil and coconut oil are the top recommended oils for the keto diet. Olive oil is rich in oleic acid and is linked to a lower risk of heart disease. Coconut oil, while high in saturated fat, contains medium-chain triglycerides (MCTs), which can boost ketone production. MCTs may also enhance metabolic rate and promote weight loss, particularly belly fat reduction. Portion control is essential when consuming nuts, seeds, and oils due to their calorie density.
Net Carb Counts per 1 oz (28g) Serving:
- Almonds: 3g net carbs (6g total carbs)
- Brazil nuts: 1g net carbs (3g total carbs)
- Cashews: 8g net carbs (9g total carbs)
- Macadamia nuts: 2g net carbs (4g total carbs)
- Pecans: 1g net carbs (4g total carbs)
- Pistachios: 5g net carbs (8g total carbs)
- Walnuts: 2g net carbs (4g total carbs)
- Chia seeds: 2g net carbs (12g total carbs)
- Flaxseeds: 0g net carbs (8g total carbs)
- Pumpkin seeds: 1g net carbs (3g total carbs)
- Sesame seeds: 3g net carbs (7g total carbs)
Berries
Berries are rich in antioxidants that combat inflammation and protect against disease. They are relatively low in carbohydrates and high in fiber compared to other fruits, making them suitable in moderation on a ketogenic diet.
Net Carb Counts per 1/2 Cup Serving:
- Blackberries: 3g net carbs (7g total carbs)
- Blueberries: 9g net carbs (11g total carbs)
- Raspberries: 3g net carbs (7g total carbs)
- Strawberries: 3g net carbs (6g total carbs)
Unsweetened Coffee and Tea
Plain coffee and tea are keto-friendly beverages, containing zero grams of carbohydrates, fat, or protein. Drinking 2-3 cups of coffee daily has been linked to a reduced risk of cardiovascular disease. Tea is rich in antioxidants, contains less caffeine than coffee, and offers numerous health benefits, including potential protection against cancer, high blood pressure, and cognitive decline.
Dark Chocolate and Cocoa Powder
Dark chocolate and cocoa powder can be enjoyed on a ketogenic diet, but moderation and label checking are key. The carbohydrate content varies depending on the type and portion size. Cocoa is considered a “superfood” due to its high antioxidant content. Dark chocolate, particularly varieties with a high cocoa percentage, contains flavanols, which may improve heart health by lowering blood pressure and promoting healthy arteries.
Foods to Limit on the Keto Diet
Due to the low-carbohydrate nature of the ketogenic diet, certain higher-carb foods need to be limited. These include:
- Grains
- Starchy vegetables and high-sugar fruits
- Sweetened yogurt
- Juices
- Honey, syrup, or sugar in any form
- Chips and crackers
- Baked goods, including gluten-free options
However, dietitians Emily Stone and Laura Dority, RDN, LDN, from the Keto Hope Foundation, emphasize that no food is entirely off-limits on keto. It’s about managing total carbohydrate intake and strategically “spending” your carb allowance. The general guideline is to stay under 20 to 40 grams of carbohydrates per day. “The exact carbohydrate threshold for ketosis varies from person to person, ranging from 10 to 60 grams of net carbs daily. This refers to net carbs, which are total carbs minus fiber,” explains Stone.
Dority adds that activity level plays a role: “Active individuals can often tolerate slightly more carbs (closer to the 40-gram end) compared to sedentary individuals.”
High-Carb Foods Typically Limited on Keto
Grains
Grains such as cereal, crackers, rice, pasta, bread, and beer are high in carbohydrates. Even whole-wheat pasta and bean-based pasta are carb-dense. Consider lower-carb alternatives like spiralized vegetables or shirataki noodles. Sugary breakfast cereals and even healthy whole-grain cereals should also be limited. “A slice of bread averages 11 grams of carbs, so you could technically have a slice, but it consumes a significant portion of your daily carb allowance,” Dority points out. “For the same amount of carbs, you could enjoy a much larger serving of vegetables.”
While beer is high in carbs, dry wine and spirits are lower-carb alcoholic options that can be consumed in moderation. Alcohol intake should generally be minimal on a keto diet.
Starchy Vegetables and High-Sugar Fruits
Starchy vegetables contain more digestible carbohydrates than fiber and should be limited on a ketogenic diet. These include corn, potatoes, sweet potatoes, and beets. High-sugar fruits, which cause faster blood sugar spikes and have higher carbohydrate content than berries, should also be restricted.
Net Carb Counts for High-Sugar Fruits:
- Banana (1 medium): 24g net carbs (27g total carbs)
- Raisins (1 oz/28g): 21g net carbs (22g total carbs)
- Dates (2 large): 32g net carbs (36g total carbs)
- Mango (1 cup): 22g net carbs (25g total carbs)
- Pear (1 medium): 21g net carbs (27g total carbs)
Net Carb Counts for Starchy Vegetables:
- Corn (1 cup): 32g net carbs (36g total carbs)
- Potato (1 medium): 33g net carbs (37g total carbs)
- Sweet potato (1 medium): 20g net carbs (24g total carbs)
- Beets (1 cup, cooked): 14g net carbs (17g total carbs)
Sweetened Yogurts
Opt for plain yogurt to avoid added sugars and excess carbohydrates. Greek yogurt is a better choice than regular yogurt due to its higher protein and lower carbohydrate content.
Fruit Drinks and Juices
Fruit drinks, even 100% fruit juice, are high in fast-digesting carbohydrates that rapidly elevate blood sugar levels. Water is the preferred beverage on a keto diet.
Honey, Syrup, and Sugar in Any Form
Limit or avoid sugar, honey, maple syrup, and other forms of added sugars as they are high in carbohydrates and low in nutritional value.
Chips and Crackers
Minimize consumption of chips, crackers, and other processed, grain-based snack foods. These are typically high in carbohydrates and low in fiber.
Gluten-Free Baked Goods
Be aware that gluten-free does not automatically mean carb-free. Many gluten-free breads and muffins are as high in carbohydrates as their traditional counterparts and are often lower in fiber.
Foods and Drinks You Can Sometimes Have on the Keto Diet
While technically any food can fit into a ketogenic diet if it aligns with your daily carbohydrate limit, some foods fall into a gray area between strictly keto-friendly and high-carb.
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Dairy Milk
Dairy milk is a good source of calcium, vitamin D, potassium, and B vitamins. However, 1 cup of dairy milk contains 12 grams of sugar (lactose). Consider unsweetened almond milk, coconut milk, or other low-carb milk alternatives instead.
Beans and Legumes
Beans and legumes are rich in fiber and protein and are part of a heart-healthy dietary pattern. However, they are also relatively high in carbohydrates. They can be included in small portions on a ketogenic diet, but they can quickly consume a significant portion of your daily carbohydrate allowance.
Pros of the Ketogenic Diet
“Strong evidence supports the ketogenic diet for individuals with drug-resistant epilepsy who experience seizures,” states Dority. In the short term, many people experience weight loss on the keto diet. Dority adds, “Emerging research shows promise for keto in conditions like autism, traumatic brain injury, brain tumors, migraines, and Alzheimer’s, as well as type 2 diabetes, potentially reducing insulin needs, fasting blood sugar, A1C levels, and promoting significant weight loss.” However, more research is needed to confirm these benefits, and any positive outcomes are contingent on successfully adhering to this restrictive diet.
Cons of the Ketogenic Diet
“Like most highly restrictive diets, meeting nutritional needs on keto can be challenging,” notes Stone. “It often leads to uncomfortable side effects like constipation and the ‘keto flu.’ Furthermore, the long-term health consequences are not fully understood.” Highly restrictive diets can be difficult to maintain and may negatively impact one’s relationship with food. Other potential negative side effects of the keto diet include bad breath, hair loss, and impaired gut health.
The Bottom Line
The ketogenic diet is not a universally applicable approach, and consulting with a registered dietitian is crucial to ensure adequate nutrient intake while maintaining ketosis. While research suggests potential benefits for various conditions, the keto diet is very challenging for most individuals to sustain long-term. The long-term effects on overall health require further investigation. EatingWell advocates for a balanced approach that includes nutritious foods like whole grains, legumes, fruits, and vegetables. If you are considering a keto diet, working with a Registered Dietitian Nutritionist (RDN) is highly recommended to develop a personalized plan.
