The ketogenic diet, often simply referred to as the keto diet, is characterized by its high-fat, moderate-protein, and very low-carbohydrate composition. While carbohydrates are typically the body’s primary energy source, a strict keto diet drastically reduces carbohydrate intake to just 5% to 10% of total daily calories. This significant reduction in carbs induces a metabolic state known as ketosis. In ketosis, the body shifts from burning glucose to burning fat for fuel. This process involves breaking down stored fat into molecules called ketones, which then serve as the primary energy source in the absence of sufficient blood sugar from carbohydrates. Once ketosis is achieved, most cells in the body will utilize ketones for energy until carbohydrate consumption is resumed.
Historically, the ketogenic diet was primarily a therapeutic tool used in clinical settings to manage seizures in children with epilepsy. However, its applications have expanded considerably. “Now there is a lot of interest in the diet’s effectiveness in helping with other 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 strategy for weight loss.
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Even with an understanding of the keto diet’s macronutrient ratios—very low-carb, high-fat, moderate-protein—navigating the specifics of what is keto diet foods can be perplexing. This guide clarifies the food choices on a ketogenic diet, categorizing foods into those you can freely enjoy, those to limit, and those to consume in moderation.
Foods You Can Eat on the Ketogenic Diet
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Here’s an extensive list of low-carb foods perfectly suited for a ketogenic diet, making it easier to understand what is keto diet foods:
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Fish and Seafood: Excellent sources of protein and essential nutrients like B vitamins, potassium, and selenium, fish and seafood are naturally carb-free. Fatty fish such as 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 and are associated with reduced risk of chronic diseases and improved mental health. Aim for at least two 3-ounce servings of fatty fish per week. Examples include cod, shrimp, crab, lobster, and trout.
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Low-Carb Vegetables: Non-starchy vegetables are foundational to what is keto diet foods. They are low in calories and carbohydrates but packed with vitamins, minerals (like vitamin C), and antioxidants. Focus on vegetables with less than 8 grams of net carbs per cup (net carbs = total carbs – fiber). Excellent choices include broccoli, cauliflower, spinach, kale, asparagus, Brussels sprouts, cucumber, zucchini, bell peppers, and green beans.
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Cheese: Cheese is a keto dieter’s friend as it contains virtually zero carbohydrates and is high in fat, along with protein and calcium. A variety of cheeses can be incorporated into a keto meal plan, such as cheddar, mozzarella, cream cheese, parmesan, and blue cheese. Be mindful of saturated fat content, as a 1-ounce slice of Cheddar cheese contains about 5g of saturated fat.
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Plain Greek Yogurt and Cottage Cheese: These dairy options are protein-rich and calcium-rich, suitable in moderation for what is keto diet foods. Plain Greek yogurt offers around 8g of carbohydrates and 20g of protein per 7 ounces, while 8 ounces of cottage cheese has just over 6g of carbohydrates and 28g of protein. Higher-fat versions are preferable on keto to enhance satiety.
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Avocados: Avocados are a prime example of heart-healthy fats in what is keto diet foods. Rich in monounsaturated fat and potassium, half a medium avocado provides approximately 6g of total carbohydrates (4.5g fiber) and 360mg of potassium. Incorporating plant fats like avocados can help reduce the risk of cardiovascular disease and type 2 diabetes.
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Meat and Poultry: Meat and poultry are staples in what is keto diet foods due to their high lean protein content and zero carbohydrates. Fresh meats like beef, pork, lamb, chicken, turkey, and game meats are all keto-friendly. While processed meats such as bacon and sausage are permissible, they should be limited in favor of leaner options due to heart health concerns.
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Eggs: Eggs are nutritional powerhouses, loaded with protein, B vitamins, minerals, and antioxidants, and contain zero carbohydrates. Two large eggs provide over 12g of protein and promote feelings of fullness. They also contain lutein and zeaxanthin, beneficial for eye health, making them a key component of what is keto diet foods.
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Nuts, Seeds, and Healthy Oils: Nuts and seeds are excellent sources of healthy polyunsaturated and monounsaturated fats, fiber, and protein, while being very low in net carbs, making them ideal for what is keto diet foods. Olive oil and coconut oil are particularly recommended. Olive oil is rich in oleic acid and linked to lower heart disease risk. Coconut oil contains medium-chain triglycerides (MCTs) that can boost ketone production and potentially aid in weight loss. Portion control is important when consuming nuts, seeds, and oils due to their calorie density.
Net Carb Counts per 1 oz (28g) Serving:
- Almonds: 3g
- Brazil nuts: 1g
- Cashews: 8g
- Macadamia nuts: 2g
- Pecans: 1g
- Pistachios: 5g
- Walnuts: 2g
- Chia seeds: 2g
- Flaxseeds: 0g
- Pumpkin seeds: 1g
- Sesame seeds: 3g
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Berries: Berries offer a touch of sweetness in what is keto diet foods while being rich in antioxidants, fiber, and lower in carbs compared to other fruits.
Net Carb Counts per 1/2 Cup Serving:
- Blackberries: 3g
- Blueberries: 9g
- Raspberries: 3g
- Strawberries: 3g
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Unsweetened Coffee and Tea: Plain coffee and tea are carb-free, fat-free, and protein-free, making them perfectly acceptable beverages on the keto diet. Coffee consumption is linked to a reduced risk of cardiovascular disease, and tea is rich in antioxidants with numerous health benefits.
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Dark Chocolate and Cocoa Powder: Dark chocolate and cocoa powder can be included in what is keto diet foods in moderation. Opt for dark chocolate with a high cocoa percentage (70% or more) and check labels for carb content. Cocoa is rich in antioxidants, and dark chocolate contains flavanols that may support heart health.
Foods to Limit on the Keto Diet
Given the low-carbohydrate nature of the keto diet, certain higher-carb foods need to be limited. Understanding what is not keto diet foods is equally important:
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Grains: Grains such as wheat, rice, oats, and corn, including products like bread, pasta, cereal, crackers, and beer, are high in carbohydrates and should be significantly restricted or avoided. Even whole-wheat and bean-based pasta are too high in carbs. Consider low-carb alternatives like spiralized vegetables or shirataki noodles.
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Starchy Vegetables and High-Sugar Fruits: Starchy vegetables like potatoes, corn, sweet potatoes, and beets, along with high-sugar fruits such as bananas, grapes, mangoes, and dried fruits, are higher in digestible carbohydrates and should be limited on keto. Berries are a better fruit choice due to their lower sugar content.
Net Carb Counts for High-Sugar Fruits:
- Banana (1 medium): 24g
- Raisins (1 oz/28g): 21g
- Dates (2 large): 32g
- Mango (1 cup): 22g
- Pear (1 medium): 21g
Net Carb Counts for Starchy Vegetables:
- Corn (1 cup): 32g
- Potato (1 medium): 33g
- Sweet potato (1 medium): 20g
- Beets (1 cup, cooked): 14g
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Sweetened Yogurts: Flavored or sweetened yogurts are often high in added sugars, increasing their carbohydrate content. Stick to plain yogurt and sweeten it yourself with keto-friendly sweeteners if desired.
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Fruit Drinks and Juices: Fruit juices, even 100% fruit juice, are concentrated sources of fast-digesting carbohydrates that can spike blood sugar. Water is the best beverage choice on a keto diet.
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Honey, Syrup, and Sugar in Any Form: Sugar, honey, maple syrup, agave, and other forms of added sugars are high in carbohydrates and low in nutrients, and should be strictly limited in what is keto diet foods.
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Chips and Crackers: Processed snack foods like chips, crackers, and many grain-based snacks are high in carbohydrates and low in fiber, making them unsuitable for a keto diet.
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Gluten-Free Baked Goods: While gluten-free, many gluten-free baked goods are still high in carbohydrates, often comparable to traditional baked goods. They may also be lower in fiber. Always check nutrition labels.
Foods and Drinks You Can Sometimes Have on the Keto Diet
Some foods fall into a gray area, being neither strictly high-carb nor definitively low-carb. These can be included in moderation as part of what is keto diet foods, provided they fit within your daily carbohydrate limit:
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Dairy Milk: While a good source of calcium and vitamin D, dairy milk contains lactose, a sugar, contributing 12g of carbohydrates per cup. Opt for low-carb milk alternatives like unsweetened almond milk, coconut milk, or flax milk.
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Beans and Legumes: Beans and legumes like black beans, chickpeas, lentils, and kidney beans are high in fiber and protein and part of a healthy diet, but they are also relatively high in carbohydrates. They can be included in small portions but should be carefully measured and may consume a significant portion of your daily carb allowance.
Pros of the Ketogenic Diet
The ketogenic diet has demonstrated benefits, particularly for individuals with drug-resistant epilepsy. Short-term weight loss is commonly reported. Emerging research suggests potential benefits for conditions like autism, traumatic brain injury, brain tumors, migraines, Alzheimer’s disease, and type 2 diabetes, including improvements in insulin sensitivity, blood sugar levels, and weight management. However, more research is needed to fully validate these claims, and benefits are contingent on strict adherence to the diet.
Cons of the Ketogenic Diet
The restrictive nature of the keto diet can make it challenging to meet nutritional needs. Common side effects include constipation, the “keto flu” (fatigue, headache, nausea), bad breath, hair loss, and potential negative impacts on gut health. Long-term health consequences are not yet fully understood. Highly restrictive diets can also negatively affect one’s relationship with food.
The Bottom Line
The keto diet is not a universally suitable approach. Consulting a registered dietitian is crucial to ensure nutritional adequacy and safe implementation. While promising research exists for certain conditions, the long-term effects and sustainability of the keto diet are still under investigation. It’s important to consider that EatingWell advocates for a balanced approach to eating that includes a variety of nutritious foods, including whole grains, legumes, fruits, and vegetables, which are often restricted on a strict ketogenic diet. If considering keto, professional guidance from an RDN is highly recommended to create a personalized and safe plan.
