The ketogenic diet is a popular dietary approach revolving around the principle of drastically reducing carbohydrate intake and replacing it with fats. This shift encourages the body to burn fat for energy, leading to potential health benefits like weight loss and reduced risk for certain diseases. This comprehensive guide will provide you with everything you need to know about the keto diet, including what to eat, what to avoid, and how to make it work for you.
Keto Basics: Understanding the Ketogenic Diet
The ketogenic diet, often shortened to "keto," shares similarities with the Atkins and other low-carb diets. It's a very low-carb, high-fat diet that forces the body into a metabolic state known as ketosis. When carbs are significantly reduced, the body becomes efficient at burning fat for energy, converting fat into ketones in the liver to fuel the brain.
This dietary change leads to significant reductions in blood sugar and insulin levels, contributing to the diet's health benefits.
Types of Ketogenic Diets
There are several variations of the ketogenic diet, each with its own specific approach:
- Standard Ketogenic Diet (SKD): The most common and well-researched version, the SKD is a very low-carb, moderate-protein, and high-fat diet, typically consisting of 70% fat, 20% protein, and 10% carbs.
- Cyclical Ketogenic Diet (CKD): This diet incorporates periods of higher carb refeeds, such as 5 ketogenic days followed by 2 high-carb days, often used by bodybuilders or athletes.
- Targeted Ketogenic Diet (TKD): The TKD allows for the addition of carbs around workouts to fuel performance, also favored by athletes.
- High-Protein Ketogenic Diet: Similar to the SKD but with a higher protein intake, often with a ratio of 60% fat, 35% protein, and 5% carbs.
The standard ketogenic diet (SKD) is the most researched and recommended.
Read also: High-Fiber Diet for Better Health
Ketosis: How it Works
Ketosis is a metabolic state where the body utilizes fat for fuel instead of carbohydrates. This occurs when carbohydrate consumption is significantly reduced, limiting the body's supply of glucose (sugar), the primary energy source for cells.
Following a ketogenic diet is the most effective way to enter ketosis. This generally means limiting carb consumption to around 20 to 50 grams per day while increasing the intake of fats from sources like meat, fish, eggs, nuts, and healthy oils.
Moderate protein consumption is also important, as high amounts of protein can be converted into glucose, potentially slowing down the transition into ketosis.
Intermittent fasting can also help accelerate the process of entering ketosis by limiting food intake to around 8 hours per day and fasting for the remaining 16 hours.
Ketone levels in the body can be measured through blood, urine, and breath tests to determine if you’ve entered ketosis. Increased thirst, dry mouth, frequent urination, and decreased hunger or appetite can also indicate that you’ve entered ketosis.
Read also: Supporting Detoxification
Health Benefits of the Ketogenic Diet
A ketogenic diet is an effective way to lose weight and lower risk factors for disease. Research suggests that the ketogenic diet may be as effective for weight loss as a low-fat diet. The diet's filling nature can lead to weight loss without the need for calorie counting or strict food tracking.
One review of 13 studies found that a very low-carb, ketogenic diet was slightly more effective for long-term weight loss than a low-fat diet, with keto dieters losing an average of 2 pounds (0.9 kg) more. Another study in older adults showed that those following a ketogenic diet for 8 weeks lost nearly five times as much total body fat as those on a low-fat diet.
The increased ketones, lower blood sugar levels, and improved insulin sensitivity associated with the keto diet may also contribute to its effectiveness.
Managing Diabetes
Diabetes is characterized by changes in metabolism, high blood sugar, and impaired insulin function. The ketogenic diet can improve insulin sensitivity, with one older study showing a 75% improvement.
A small study in women with type 2 diabetes found that following a ketogenic diet for 90 days significantly reduced levels of hemoglobin A1C, a measure of long-term blood sugar management. Another study in people with type 2 diabetes showed that those following a ketogenic diet lost an average of 26.2 pounds (11.9 kg) over a 2-year period, along with improved blood sugar management and decreased use of blood sugar medications.
Read also: The Definitive Guide to Flourless, Sugar-Free Dieting
The ketogenic diet can boost insulin sensitivity and cause fat loss, leading to significant health benefits for people with type 2 diabetes or prediabetes.
Other Potential Health Benefits
Studies have shown that the ketogenic diet may have benefits for a wide variety of different health conditions:
- Heart disease: The ketogenic diet can help improve risk factors like body fat, HDL (good) cholesterol levels, blood pressure, and blood sugar.
- Cancer: The diet is being explored as an additional treatment for cancer, as it may help slow tumor growth.
- Alzheimer’s disease: The keto diet may help reduce symptoms of Alzheimer’s disease and slow its progression.
- Epilepsy: Research has shown that the ketogenic diet can cause significant reductions in seizures in epileptic children.
- Parkinson’s disease: One study found that the diet helped improve symptoms of Parkinson’s disease, although more research is needed.
- Polycystic ovary syndrome: The ketogenic diet can help reduce insulin levels, which may play a key role in polycystic ovary syndrome.
- Brain injuries: Some research suggests that the diet could improve outcomes of traumatic brain injuries.
Research into many of these areas is ongoing and not yet conclusive.
Foods to Avoid on a Ketogenic Diet
To achieve and maintain ketosis, certain foods need to be significantly reduced or eliminated from your diet:
- Sugary foods: Soda, fruit juice, smoothies, cake, ice cream, candy, etc.
- Grains or starches: Wheat-based products, rice, pasta, cereal, etc.
- Fruit: All fruit, except small portions of berries or strawberries.
- Beans or legumes: Peas, kidney beans, lentils, chickpeas, etc.
- Root vegetables and tubers: Potatoes, sweet potatoes, carrots, parsnips, etc.
- Low-fat or diet products: Low-fat mayonnaise, salad dressings, and condiments.
- Some condiments or sauces: Barbecue sauce, honey mustard, teriyaki sauce, ketchup, etc.
- Unhealthy fats: Processed vegetable oils, mayonnaise, etc.
- Alcohol: Beer, wine, liquor, mixed drinks.
- Sugar-free diet foods: Sugar-free candies, syrups, puddings, sweeteners, desserts, etc.
Avoid carb-based foods like grains, sugars, legumes, rice, potatoes, candy, juice, and even most fruits.
Foods to Embrace on a Ketogenic Diet
The majority of your meals should be based around these foods:
- Meat: Red meat, steak, ham, sausage, bacon, chicken, and turkey.
- Fatty fish: Salmon, trout, tuna, and mackerel.
- Eggs: Pastured or omega-3 whole eggs.
- Butter and cream: Grass-fed butter and heavy cream.
- Cheese: Unprocessed cheeses like cheddar, goat, cream, blue, or mozzarella.
- Nuts and seeds: Almonds, walnuts, flaxseeds, pumpkin seeds, chia seeds, etc.
- Healthy oils: Extra virgin olive oil, and avocado oil.
- Avocados: Whole avocados or freshly made guacamole.
- Low carb veggies: Green veggies, tomatoes, onions, peppers, etc.
- Condiments: Salt, pepper, herbs, and spices.
It’s best to base your diet mostly on whole, single-ingredient foods.
A Sample Keto Meal Plan
Here is a sample meal plan to give you an idea of what a week on the ketogenic diet might look like:
- Monday
- Breakfast: Veggie and egg muffins with tomatoes
- Lunch: Chicken salad with olive oil, feta cheese, olives, and a side salad
- Dinner: Salmon with asparagus cooked in butter
- Tuesday
- Breakfast: Egg, tomato, basil, and spinach omelet
- Lunch: Almond milk, peanut butter, spinach, cocoa powder, and stevia milkshake with a side of sliced strawberries
- Dinner: Cheese-shell tacos with salsa
- Wednesday
- Breakfast: Nut milk chia pudding topped with coconut and blackberries
- Lunch: Avocado shrimp salad
- Dinner: Pork chops with Parmesan cheese, broccoli, and salad
- Thursday
- Breakfast: Omelet with avocado, salsa, peppers, onion, and spices
- Lunch: A handful of nuts and celery sticks with guacamole and salsa
- Dinner: Chicken stuffed with pesto and cream cheese, and a side of grilled zucchini
- Friday
- Breakfast: Sugar-free Greek, whole milk yogurt with peanut butter, cocoa powder, and berries
- Lunch: Ground beef lettuce wrap tacos with sliced bell peppers
- Dinner: Loaded cauliflower and mixed veggies
- Saturday
- Breakfast: Cream cheese pancakes with blueberries and a side of grilled mushrooms
- Lunch: Zucchini and beet “noodle” salad
- Dinner: White fish cooked in olive oil with kale and toasted pine nuts
- Sunday
- Breakfast: Fried eggs with mushrooms
- Lunch: Low carb sesame chicken and broccoli
- Dinner: Spaghetti squash Bolognese
Always try to rotate the vegetables and meat over the long term, as each type provides different nutrients and health benefits.
Keto-Friendly Foods: A Detailed Guide
A keto diet revolves around eating high-fat, low-carb foods. Followers of this diet may consume a variety of animal proteins, dairy, vegetables, other plant-based foods, and fats and oils.
Some people on keto count their total carb intake, while others count net carbs. Net carbs refer to total carbs minus fiber, which is indigestible and therefore cannot be broken down and absorbed by your body.
Here's a detailed list of healthy foods to eat on the keto diet:
- Seafood: Fish and shellfish are very keto-friendly. Salmon and other fish are not only nearly carb-free but also rich in B vitamins, potassium, and selenium. Fatty fish like salmon, sardines, and mackerel are high in omega-3 fats, which may help manage blood sugar levels and lower insulin levels in people with diabetes. Frequent fish intake is also linked to improved brain health and a decreased risk of disease.
- Meat and poultry: Fresh meat and poultry contain no carbs and are rich in B vitamins and several important minerals. They’re also a great source of high-quality protein, which may help preserve muscle mass during a very low-carb diet. Always go for organic beef from grass-fed cows, it really makes a difference!
- Eggs: One large egg (50 g) contains less than 1 g of carbs and about 6 g of protein. In addition, eggs have been shown to trigger hormones that increase feelings of fullness. It’s important to eat whole eggs rather than egg whites since most of an egg’s nutrients are found in the yolk, including antioxidants lutein and zeaxanthin, which protect eye health.
- Cheese: Most cheeses are very low in carbs and high in fat, making them a great fit for the keto diet. Just 1 oz (28 g) of cheddar cheese provides 1 g of carbs, 6 g of protein, and a good amount of calcium. The harder the cheese, the fewer carbs, but experiment to find some varieties you enjoy.
- Keto cheese list: blue cheese, Brie, Camembert, cheddar, chevre, Colby jack, cottage cheese, cream cheese, feta, goat cheese, halloumi, Havarti, Limburger, Manchego, mascarpone, mozzarella, Muenster, Parmesan, pepper jack, provolone, Romano, string cheese, Swiss cheese.
- Plain Greek yogurt and cottage cheese: While they contain some carbs, you can eat them in moderation on keto. Both Greek yogurt and cottage cheese have been shown to help decrease appetite and promote feelings of fullness.
- Cream and half-and-half: Both cream and half-and-half are very low in carbs and high in fat, making them ideal for keto. Despite this, it’s best to enjoy them in moderation.
- Unsweetened plant-based milk: Several varieties of plant-based milk, including soy, almond, and coconut milk, are keto-friendly. Consider using unsweetened versions, as sweetened options have too much sugar to be considered appropriate for keto.
- Green leafy vegetables: Green leafy veggies are low in carbs and rich sources of vitamins, minerals, and antioxidants. In particular, dark leafy greens like spinach, kale, and collard greens are packed with vitamin K and iron. Greens add bulk to your meals without drastically increasing the carb count.
- Keto-friendly leafy greens: lettuce, baby spinach, arugula, escarole, and frisee, bok choy, collard greens, mustard greens, kale, spinach, Swiss chard, and cabbage, thyme, sage, mint, oregano, dill, parsley, cilantro, basil, rosemary, and lemongrass.
- Peppers: Several varieties of peppers exist, all of which are appropriate for the keto diet. While they’re technically fruits, they’re treated like vegetables in cooking.
- Summer squash: Summer squashes, such as yellow squash and zucchini, are versatile and low in carbs. Zucchini is extremely popular on keto. Using a spiralizer, you can make zucchini noodles, which are an excellent substitute for pasta or noodles.
- High-fat veggies: Avocados and olives are unique among vegetables in that they’re fairly high in fat. They also contain fiber and are low in net carbs. Regularly eating avocados may also help improve heart health risk factors, including lower levels of LDL “bad” cholesterol.
- Other nonstarchy vegetables: Several other nonstarchy vegetables are low in calories and carbs yet full of nutrients and antioxidants. Low carb veggies make great substitutes for high carb foods.
- Keto vegetable list: asparagus, broccoli, cabbage, cauliflower, mushrooms, cucumber, green beans, eggplant, tomatoes, radishes, Brussels sprouts, celery, okra. Carrots are too starchy for keto, while cauliflower is more acceptable because of its low net carb count.
- Nuts and seeds: Nuts and seeds are high in fat and low in carbs. Frequent nut intake is linked to a reduced risk of heart disease, certain cancers, depression, and other chronic diseases. Furthermore, nuts and seeds are high in fiber, which can help you feel full, lower your calorie intake, and reduce your risk of chronic diseases.
- Keto-friendly nut and seed options: almonds, macadamia nuts, pecans, walnuts, chia seeds, flaxseeds.
- Berries: Most fruits are too high in carbs to eat on the keto diet, but berries are an exception. These tiny fruits are loaded with antioxidants that may reduce inflammation and help protect against disease.
- Shirataki noodles: Shirataki noodles are a fantastic addition to the keto diet. They contain less than 1 g of net carbs and only 15 calories per serving because they’re mostly water.
- Dark chocolate and cocoa powder: You can eat chocolate on keto, but it’s important to choose dark chocolate that contains a minimum of 70% cocoa solids - preferably more - and eat it in moderation.
- Olive oil: As a pure fat source, olive oil contains no carbs. It’s an ideal base for salad dressings and mayonnaise. It’s also best to use olive oil for low heat cooking or add it to dishes after they’ve been cooked.
- Butter and ghee: Butter and ghee are good fats to include while on the keto diet. Butter and ghee are also carb-free.
- Unsweetened coffee and tea: Coffee and tea are healthy, carb-free drinks. They contain caffeine, which increases your metabolism and may help improve your physical performance, alertness, and mood.
- Unsweetened sparkling water: If you’re looking for a keto-friendly alternative to soda, unsweetened sparkling water is a great choice. Be sure to check the label, as extra carbs can add up quickly.
Eating Out on Keto
When eating out, select a meat-, fish-, or egg-based dish. Order extra veggies instead of carbs or starches, and have cheese for dessert.
At Mexican restaurants, you can enjoy any type of meat with extra cheese, guacamole, salsa, and sour cream. For dessert, ask for a mixed cheese board or berries with cream.
Potential Side Effects and How to Manage Them
Although the ketogenic diet is usually safe for most healthy people, there may be some initial side effects while your body adapts. These effects are often referred to as the "keto flu".
Reported keto flu symptoms include diarrhea, constipation, and vomiting. Other less common symptoms include poor energy and mental function, increased hunger, sleep issues, nausea, digestive discomfort, and decreased exercise performance.
To minimize these effects, you can try a regular low-carb diet for the first few weeks to teach your body to burn more fat before completely eliminating carbs.
A ketogenic diet can also change the water and mineral balance of your body, so adding extra salt to your meals or taking mineral supplements may help. Talk to your doctor about your nutritional needs.
At least in the beginning, it’s important to eat until you’re full and avoid restricting calories too much. Usually, a ketogenic diet causes weight loss without intentional calorie restriction.
While the keto diet has its benefits, staying on it in the long term may have some negative effects, including risks of the following: low protein in the blood, extra fat in the liver, kidney stones, and micronutrient deficiencies.
A type of medication called sodium-glucose cotransporter 2 (SGLT2) inhibitors for type 2 diabetes can increase the risk for diabetic ketoacidosis, a dangerous condition that increases blood acidity. Anyone taking this medication should avoid the keto diet.
More research is being done to determine the safety of the keto diet in the long term. Keep your doctor informed of your eating plan to guide your choices.
Helpful Supplements for the Keto Diet
Although no supplements are required, some can be useful:
- MCT oil: Added to drinks or yogurt, MCT oil provides energy and helps increase ketone levels.
- Minerals: Added salt and other minerals can be important when starting out due to shifts in water and mineral balance.
- Caffeine: Caffeine can have benefits for energy, fat loss, and performance.
- Exogenous ketones: This supplement may help raise the body’s ketone levels.
- Creatine: Creatine provides numerous benefits for health and performance. This can help if you are combining a ketogenic diet with exercise.
- Whey: Use half a scoop of whey protein in shakes or yogurt to increase your daily protein intake.
Common Questions About the Ketogenic Diet
Here are answers to some of the most common questions about the ketogenic diet:
- Can I ever eat carbs again? Yes. However, it’s important to significantly reduce your carb intake initially. After the first 2 to 3 months, you can eat carbs on special occasions - just return to the diet immediately after.
- Will I lose muscle? There’s a risk of losing some muscle on any diet. However, protein intake and high ketone levels may help minimize muscle loss, especially if you lift weights.
- Can I build muscle on a ketogenic diet? Yes, but it may not work as well as on a moderate carb diet.
Keto Diet for Weight Loss
For weight loss on keto, stock up on proteins like chicken, fish, eggs, and grass-fed beef, healthy fats like olive oil and butter, and low-carb veggies like broccoli and leafy greens.
Research suggests that following the keto diet can help you burn fat while making you feel less hungry. However, some of the weight loss you see at the beginning can actually be due to the release of stored water. Very restrictive diets that lead to fast weight loss can be bad for your health and actually make it harder to maintain your weight goals long-term. Research has shown that losing weight quickly can slow down the rate at which your body burns the energy it gets from food.
Foods to Limit or Avoid on Keto
Off-limits foods on keto include anything highly processed with added sugars that kick you out of ketosis and additives that can cause inflammation and health problems. You should also limit your consumption of high-carb fruits, legumes, grains, and starchy vegetables.
- Skip Croutons and Sprinkle Hemp Hearts on Your Salad: Just ⅓ cup of croutons contains almost 8 g of net carbs. Instead, add crunch with hemp hearts. 2 tablespoon (tbsp) of hemp hearts has less than 1 net carb.
- Bypass Starchy Peas and Opt for Broccoli as Your Veggie Side: Peas have a higher amount of carbs than other green veggies - 12 g net carbs per cup. According to the USDA, 1 cup of chopped broccoli contains 3.7 g net carbs, a cup of zucchini has 2.6 g of net carbs, and raw spinach has 0.4 g of net carbs per cup.
- Low-Calorie Snacks May Still Be High-Carb - Choose Sunflower Seeds Instead: Those include sunflower seeds, toasted pumpkin seeds, and nuts.
- Potato Chips Aren’t Keto-Friendly, So Try This DIY Seaweed Snack: A 1 ounce (oz) serving has 14.4 g of net carbs. Here’s a worthy keto- and heart-friendly snack substitute to scratch that salty itch: Finely chop up your favorite nuts and seeds in a food processor, and add white vinegar and salt. Roll up the mixture in sheets of nori seaweed (like a cigar) and cook in the oven for 5 to 10 minutes until crispy.
- Bananas Are High Carb, but Berries Can Work on Keto: One banana has more than 21 g of net carbs. Raspberries are packed with fiber, making them a good go-to. They contain 1.7 g of net carbs per ¼ cup.
- Honey-Baked Ham Is Glazed in Sugar, but Deli Meat Can Be Compliant: One serving (about 1.9 oz) contains 4 g of net carbs. Traditional sliced deli ham, which has 0 g of carbs per slice. Still, you’ll want to read the ingredients list to make sure there’s no added sugar.
- Margarine Isn’t Keto-Friendly, So Opt for EVOO: Nasar suggests using extra-virgin olive oil because research backs up olive oil’s heart-healthy properties.
- Piña Coladas Are Sugar Bombs - Sip on a Vodka Soda Instead: One 4.5 oz piña colada has 31.6 g of net carbs. A vodka soda has zero carbs per drink.
- Beer Is Packed With Carbs, but Light Beer in Moderation May Be Okay: Even light beers generally pack 5.8 g of carbohydrates per 12 oz can.
- Sweet Potatoes Aren’t Okay on Keto, but Cauliflower Is: A medium sweet spud has about 20 g of carbs. One cup of cauliflower florets contains only 3.2 g of net carbs.
- Cow’s Milk Is a Major Source of Carbs; Reach for Almond Milk Instead: One cup of whole milk has 11.5 g of net carbs. Almond milk. With about 1 net carb g per cup, this nondairy alternative can work in your keto diet. Soy milk is another great option, with 1.9 g net carb and 8 g of protein per cup. Just be sure to read the ingredients and choose an unsweetened variety.
- Trail Mix Is a No-No; Raw or Salted Nuts Are a Go: A standard 1 oz serving (a small amount, by the way) has 12.7 g of carbs. An ounce of almonds has 2.6 g of net carbs.
- Carrots, Though Healthy, Are Starchier Than, Say, Bell Peppers: One medium carrot has 4.1 g of net carbs. An entire small pepper has just 2.9 g of net carbs.
- Soda Isn’t Allowed on Keto, but Unsweetened Sparkling Water Is a Great Choice: Cola has 36.8 g of sugar per 12 oz can.
- Butternut Squash Is Too Starchy, yet Spaghetti Squash Is Keto-Friendly: One cup of cubed squash has more than 13.6 g of net carbs.
Practical Tips for Keto Success
- Meal Planning and Grocery Shopping: A keto grocery list helps you plan structured meals that meet your macros and avoid impulse purchases, especially foods that can kick you out of ketosis.
- Prioritize Versatile Ingredients: Maximizing your keto-friendly grocery haul means focusing on versatile, long-lasting ingredients that work across multiple meals. Freezer-friendly items like frozen shrimp and pre-cut veggies save time and reduce waste. Plan meals around overlapping ingredients to minimize extra shopping trips and keep your keto diet on budget.
- Start with Easy Recipes: If you’re having trouble with keto meal prep, start with easy-to-follow recipes that keep your macros balanced and boost ketosis.
- Stock Up on Keto Essentials: Keto beginners should stock up on essentials that keep them in ketosis. That includes low-carb foods like eggs, chicken, and fatty fish for protein and healthy fats like avocados, butter, and olive oil. Stick to low-carb fruits and veggies and replace pantry staples with lower-carb versions like sugar-free sweeteners and keto-friendly flours. If you’re meal prepping, buy in bulk and freeze the extras.