Here’s a primer: The popular ketogenic diet is a low-carb, high-fat diet. Meanwhile, you’ll aim for moderate protein in your meal plan. In other words, it’s a far cry from the fad low-fat diet approaches of yesteryear — and, really, from other diets in general. The main way ketogenic diets differ from other popular low-carb diets is that keto diets aim to drive your body into a metabolic state called ketosis, in which the body starts burning stored fat as a source of energy, instead of carbohydrates, says Stacey Mattinson, RDN, who is based in Austin, Texas. Once you’ve adjusted your food intake to get there, your body can enter a state of ketosis in 1 to 3 days, she adds. Nutritional ketosis can also happen if you eat another restrictive diet — specifically, a very low-calorie diet. Typically, that type of diet consists of 600 to 800 total calories per day and is doctor supervised and medically recommended. Another thing to keep in mind: The potential benefits of keto discussed here are for the popular, standard ketogenic diet, not other spins on the keto diet, such as the cyclical ketogenic diet or the targeted ketogenic diet. Those keto diets have even less research on them. While the classic keto diet has a wealth of research about its benefits for those with epilepsy, we won’t be discussing that here either. The good news: Mattison called research on keto supporting blood sugar management in people with diabetes “promising.” “A ketogenic diet may cause a reduction in A1C — a key test for diabetes that measures a person’s average blood sugar control over two to three months — something that may help you reduce medication use,” she says. Despite the ability of keto to lower blood sugar levels, one big concern is that you eat a lot of fat on keto, and those may be saturated fats, which are unhealthy and associated with a higher risk of cardiovascular disease, or heart disease, when eaten in excess. In one trial involving 33 people with prediabetes or diabetes, going on a ketogenic diet or a Mediterranean diet, which is a type of plant-based diet, for 12 weeks improved blood sugar control, as measured by A1C levels. That said, neither the low-carb, high-fat diet nor the plant-based diet performed better than the other. One benefit of the low-carb diet was that it reduced triglycerides better than the Mediterranean diet, and yet there were downsides: The keto diet increased LDL (“bad”) cholesterol, and those on the diet got fewer nutrients, particularly folate, vitamin C, magnesium, and fiber, because of everything that the keto diet cuts out (e.g., fruits, whole grains). The overall takeaway, researchers said, is that it’s best to work with your clinician on making an informed choice that is suited your health concerns, food preferences, and lifestyle. Despite the potential blood sugar benefits of keto, because people with type 2 diabetes have an increased risk of heart disease, there is a specific concern that eating so much saturated fat may drive up LDL cholesterol levels and further increase the odds of heart problems. So, if you have type 2 diabetes, talk to your doctor before attempting a ketogenic diet, especially if you have other risk factors for heart disease, such as high blood pressure. The doctor may recommend a different weight loss diet for you that may help improve your blood sugar levels, such as a reduced-calorie diet. Those with epilepsy should also consult their doctor before using a ketogenic diet as part of their treatment plan. If you do opt to go through with the keto diet, consider working with a registered dietitian nutritionist who is also a certified diabetes care and education specialist. They can help you develop a healthy low-carb meal plan that is high in fat but low in saturated fats, and which contains plenty of healthy foods such as low-carb veggies. Besides diabetes, the keto diet may also help improve short- and long-term cognition among people who are living with Alzheimer’s disease and experiencing mild cognitive impairment, according to a systematic review of randomized controlled trials. Researchers caution that further research is needed to confirm these findings and prove a cause-and-effect relationship between the ketogenic diet and preventing dementia.
Keto and Weight Loss
Looking to lower your body fat percentage? You’ve probably heard that keto diets can help — and that they can make a big impact on your weight right away. There may be some truth to that notion, although how much weight you lose will vary by individual. “Ketogenic diets will cause you to lose weight within the first week,” says Mattinson. Thanks to its low-carb nature, keto will force the body to first use up all its glycogen stores, which is the storage form of carbohydrates, she explains. With depleted glycogen, you’ll drop water weight. While it can be motivating to see the number on the scale go down, keep in mind that most of this is water loss initially. But the ketogenic diet can also be an effective weight loss option over time. One review suggested that this low-carb diet can spur fat loss in people with obesity when used for a couple of weeks and for up to one year. And a meta-analysis noted that one likely reason for weight loss is that all of the fat consumed when on this diet may suppress hunger. One downside of the ketogenic diet for weight loss is that it’s difficult to maintain, especially compared to a traditional diet or other diets that have less stringent rules. “Studies show that weight loss results from being on a low-carb diet for more than 12 months tend to be the same as being on a normal, healthy diet,” says Mattinson. While you may be eating more satiating fats (like peanut butter, regular butter, or avocado), the very low-carbohydrate nature of keto means that you are way more limited in terms of what’s allowed on the diet, which can make everyday situations, such as eating dinner with family or going out with friends, far more difficult. Because people often find this diet tough to sustain, it’s easier to rely on as a short-term diet than as a long-term lifestyle. Before starting, ask yourself what is really realistic for you, Mattinson suggests. Then get your doctor’s okay. You may also work with a local registered dietitian nutritionist to limit potential vitamin and mineral deficiencies and talk about vitamin and mineral supplements, since you won’t be eating whole grains, dairy, or fruit, and you will also eliminate many veggies. (However, you may be eating some high-fat dairy.) “A diet that eliminates entire food groups is a red flag to me. That isn’t something to take lightly or dive in to headfirst with no medical supervision,” she says. The remaining calories in the ketogenic diet come from a moderate daily protein intake — about 1 gram (g) per kilogram of body weight, so a 140-pound woman would need about 64 g of protein per day. As for total carb intake: “Every body is different, but most people maintain ketosis with between 20 and 50 g of net carbs per day,” says Mattinson. Total carbohydrates minus fiber equals net carbs, she explains. One thing to remember: “It’s easy to get ‘kicked out’ of ketosis,” says Mattinson. Meaning, if you eat something as small as a serving of blueberries, your body could exit that metabolic state, stop producing ketone bodies, and revert to burning carbohydrates for fuel rather than fat. “It’s so important to know what foods you’ll be eating before you start, and how to incorporate more fats into your diet,” says Kristen Mancinelli, RD, author of The Ketogenic Diet: A Scientifically Proven Approach to Fast, Healthy Weight Loss, who is based in New York City. If you are considering taking supplements, as noted below, check with your doctor first. Mancinelli shares her guidance on choosing nutritious foods for keto here:
Protein
Ketogenic diets aren’t high in protein (they focus on fat) so these should all be consumed in moderation. Liberally
Grass-fed beefFish, especially fatty fish, like salmonDark-meat chicken
Occasionally
BaconLow-fat proteins, like skinless chicken breast and shrimp. These are great to include in your keto diet, but add a sauce on top for some fat rather than eating them plain.
Never Though potentially high in fat, these protein sources may also contain too many carbs, and in the case of cold cuts and chicken nuggets, these typically high-sodium foods may rise blood pressure levels.
Cold cuts with added sugar (read the label)Meat that has been marinated in sugary saucesFish or chicken nuggets
Oil and Fat
Liberally
AvocadoAvocado oilOlive oil
Occasionally Limit your consumption of these oils, which should be easy to do if you’re avoiding packaged foods, where they’re often found.
Sunflower oilSafflower oilCorn oilButter (just keep in mind that this is high in saturated fat)Heavy creamWhole milkCoconut oil
Never
MargarineTrans fats
Fruits and Veggies
Liberally
Avocado (also high in healthy monounsaturated fat, and low in saturated fat, per the USDA)Leafy greens, like spinach and arugulaCeleryAsparagus
Occasionally These are great choices, but you’ll still need to count how many carbs they contain.
LeeksSpaghetti squashEggplantAvocadoRaspberriesLemonTomatoes
Never
PotatoesCornRaisins
Nuts and Seeds
Liberally
WalnutsAlmondsFlaxseed and chia seedsNut butter (unsweetened)
Occasionally
Unsweetened nut butters (almond or peanut butter)CashewsPistachios
Never
Trail mixes with dried fruitSweetened nut or seed buttersChocolate-covered nuts
Dairy Products
Liberally
Blue cheeseFeta cheeseParmesan cheeseCream cheese
Occasionally
Full-fat cottage cheeseFull-fat plain Greek yogurtFull-fat ricotta cheeseCheddar cheeseAmerican cheese
Never
MilkSweetened nonfat yogurtIce cream
Sweeteners
Liberally None — always practice moderation with sweeteners. If you’ve tried other low-carb diets, this aspect of the keto diet probably won’t be surprising. Occasionally
Artificial sweeteners, such as steviaErythritolXylitol
Never
AgaveHoneyMaple syrupWhite and brown sugars
Condiments and Sauces
Liberally
GuacamoleLemon butter sauceMayonnaise (ensure that there’s no sugar added)
Occasionally
Raw garlicTomato sauce (look for those with no added sugar)Balsamic vinegar
Never
Barbecue sauceKetchupHoney mustard
Drinks
Liberally
WaterUnsweetened almond milkBone brothPlain tea
Occasionally
Black coffee (watch caffeine consumption)Unsweetened carbonated water (limit only if bubbles make you bloated)Diet sodaZero-calorie drinksAlcohol (hard spirits, wine, low-carb beer, some alcoholic seltzers)
Never Again, these are no-nos on all low-carb diets.
SodaFruit juiceLemonade
Herbs and Spices
All herbs and spices fit in a keto or low-carbohydrate diet, but if you’re using large amounts, Mancinelli recommends counting the carbs. Liberally
Salt (salt foods to taste only, to avoid raising blood pressure levels)PepperThyme, oregano, paprika, and cayenne
Occasionally These are good choices, but they do contain some carbs.
Ground gingerGarlic powderOnion powder
Never
No herbs and spices are off limits; they’re generally okay to use in small amounts to add flavor to foods.
Supplements
Consider taking
FiberMultivitamin
Optional MCT oil may help increase ketone levels more quickly, according to one small study. (Though research isn’t yet clear.) Mancinelli says she has no recommendation about taking or avoiding them.
Avocado Oil
Per 1 Tablespoon (Tbsp) Serving 124 calories, 0 g net carbs, 0 g protein, 14 g fat, according to the USDA Benefits This is a good source of healthy unsaturated fatty acids.
Coconut Oil (in Moderation)
Per 1 Tbsp Serving 121 calories, 0 g net carbs, 0 g protein, 14 g fat, per the USDA Benefits High in saturated fats, coconut oil is a commonly used oil in keto diets, though research suggests that for heart health, it may still be best to choose unsaturated sources of fat, since the data isn’t yet clear about the risks and benefits of coconut oil, according to Harvard Health Publishing.
MCT Oil
Per 1 Tbsp Serving 130 calories, 0 g net carbs, 0 g protein, 14 g fat, according to Carrington Farms Benefits Often derived from coconut, per the Cleveland Clinic, MCT stands for medium chain triglycerides, and this oil is high in saturated fats. Limited research suggests that in small doses, MCT oil may aid with weight loss and help promote ketosis more than olive oil. One other note: Avoid MCT oil if you have a heart or liver condition.
Cheddar Cheese
Per 1-Ounce Slice 115 calories, 0 g net carbs, 7 g protein, 9 g fat, per the USDA Benefits Cheese is allowed as you please, and cheddar is a good example of its nutrition benefits. One study found an association between eating cheese and a 12 percent lower risk of type 2 diabetes, but more studies on the potential link are needed. What’s more, cheese can be high in saturated fats, so proceed with caution.
Heavy Cream (in Moderation)
Per 1 Tbsp Serving 51 calories, 0 g net carbs, 0 g protein, 5 g fat, notes the USDA Benefits This is an easy way to add calories and fat into a ketogenic diet, though it is rich in saturated fat.
Bacon
Per 1 Slice Serving 37 calories, 0 g net carbs, 3 g protein, 3 g fat, according to the USDA Benefits The green light on bacon may be one reason you’re up for sticking with a keto diet, as it can make eating occasions more enticing. Just watch the sodium content, as it can add up quickly and certainly won’t help with lowering blood pressure. And as with all the meats on this list, don’t go overboard — you don’t want to eat too much protein (or saturated fat) on keto.
Chicken Thighs
Per 1 Thigh Serving 181 calories, 0 g net carbs, 18 g protein, 12 g fat, notes the USDA Benefits Leave the skin on here for extra fat. (Skin-on, dark-meat poultry is higher in saturated fat than white meat.) One thigh is a good source of riboflavin, niacin, B6, and B12.
Eggs
Per 1 Large Egg Serving 72 calories, 0 g net carbs, 6 g protein, 5 g fat, according to the USDA Benefits Eggs contain the perfect combo of satiating protein and fat (most of which is unsaturated); they’re also high in the antioxidant mineral selenium.
Ground Beef
Per 4-Ounce Serving (Measured Raw) 375 calories, 0 g net carbs, 16 g protein, 34 g fat, notes the USDA Benefits Ground beef (made with 70 percent lean meat and 30 percent fat, which contains more saturated fat than 90 percent lean beef) is a higher-fat choice — but that’s the point here. It’s also an excellent source of vitamin B12, which is necessary to keep up your energy levels, notes research.
New York Strip Steak
Per 4-Ounce Serving of Prime Meat Trimmed to Eighth-Inch Fat 318 calories, 0 g net carbs, 22 g protein, 25 g fat, according to the USDA Benefits You’ll get an impressive amount of muscle-building protein plus satiating fat (almost half of which is saturated fat) in this option. It’s also rich in zinc, a mineral that may promote proper thyroid function, according to research.
Asparagus
Per 1 Cup (Raw) Serving 27 calories, 2 g net carbs, 3 g protein, 0 g fat, per the USDA Benefits Asparagus contains bone-building calcium, plus other minerals, such as potassium and magnesium, which have been linked with blood sugar regulation, per the National Institutes of Health Office of Dietary Supplements.
Avocado
Per Half Avocado Serving 160 calories, 2 g net carbs, 2 g protein, 15 g fat, notes the USDA Benefits This creamy fruit is packed with fiber, something that you may lack on the keto diet, as well as monounsaturated fatty acids. It is also a good source of immune-revving vitamin C, according to the National Institutes of Health Office of Dietary Supplements.
Bok Choy
Per 1 Cup (Shredded) Serving 9 calories, 1 g net carbs, 1 g protein, 0 g fat, according to the USDA Benefits Chinese cabbage is a rich source of vitamins A and C, and it offers some calcium and energy-boosting iron, notes StatPearls.
Cauliflower
Per 1 Cup (Raw) Serving 27 calories, 3 g net carbs, 2 g protein, 0 g fat, per the USDA Benefits Provides an excellent source of vitamin C; with 2 g of fiber, it counts toward your daily goal for this heart-healthy nutrient.
Celery
Per 1 Cup (Raw) Serving 14 calories, 1 g net carbs, 1 g protein, 0 g fat, according to the USDA Benefits Celery is one of the most hydrating veggies out there. These crunchy spears also contain vitamins A and K and folate.
Cucumber
Per Half Cup (Sliced) Serving 8 calories, 2 g net carbs, 0 g protein, 0 g fat, according to the USDA Benefits Cukes are high in water, making them a hydrating choice.They also offer some vitamin K, a vitamin important for proper blood clotting and bone formation.
Green Peppers
Per 1 Cup (Sliced) Serving 18 calories, 3 g net carbs, 1 g protein, 0 g fat, per the USDA Benefits Along with about a day’s worth of vitamin C, they’re also a good source of vitamin B6, which plays a role in more than 100 enzyme reactions in the body, according to the National Institutes of Health.
Lettuce
Per 1 Cup (Shredded) Serving 5 calories, 1 g net carbs, 0 g protein, 0 g fat, notes the USDA Benefits Leafy greens can add bulk to your meals for very few calories, as well as skin-strengthening vitamin A.
White Mushrooms
Per 1 Cup (Raw) Serving 15 calories, 2 g net carbs, 2 g protein, 0 g fat, per the USDA Benefits Mushrooms are known for their potential immune-boosting properties, as one study on shiitake mushrooms suggested. They’re also an excellent source of riboflavin and a good source of niacin.
Zucchini
Per 1 Cup (Sliced, Raw) Serving 19 calories, 2 g net carbs, 1 g protein, 0 g fat, according to the USDA Benefits This is a great way to sneak in additional fiber, and the veggie also contains some manganese, a mineral that helps form bone and aids in blood glucose control. Snack Sunflower seeds Lunch Spinach salad with grilled salmon Snack Celery and pepper strips dipped in guacamole Dinner Pork chop with cauliflower mash and red cabbage slaw
Day 2
Breakfast Bulletproof coffee (made with butter and coconut oil), hard-boiled eggs Snack Macadamia nuts Lunch Tuna salad stuffed in tomatoes Snack Roast beef and sliced cheese roll-ups Dinner Meatballs on zucchini noodles, topped with cream sauce
Day 3
Breakfast Cheese and veggie omelet topped with salsa Snack Plain, full-fat Greek yogurt topped with crushed pecans Lunch Sashimi takeout with miso soup Snack Smoothie made with almond milk, greens, almond butter, and protein powder Dinner Roasted chicken with asparagus and sautéed mushrooms
Day 4
Breakfast Smoothie made with almond milk, greens, almond butter, and protein powder Snack Two hard-boiled eggs Lunch Chicken tenders made with almond flour on a bed of greens with cucumbers and goat cheese Snack Sliced cheese and bell pepper slices Dinner Grilled shrimp topped with a lemon butter sauce with a side of asparagus
Day 5
Breakfast Fried eggs with bacon and a side of greens Snack A handful of walnuts with a quarter cup of berries Lunch Grass-fed burger in a lettuce “bun” topped with avocado and a side salad Snack Celery sticks dipped in almond butter Dinner Baked tofu with cauliflower rice, broccoli, and peppers, topped with a homemade peanut sauce
Day 6
Breakfast Baked eggs in avocado cups Snack Kale chips Lunch Poached salmon avocado rolls wrapped in seaweed (rice-free) Snack Meat-based bar (turkey or pork) Dinner Grilled beef kebabs with peppers and sautéed broccolini
Day 7
Breakfast Eggs scrambled with veggies, topped with salsa Snack Dried seaweed strips and cheese Lunch Sardine salad made with mayo in half an avocado Snack Turkey jerky (look for no added sugars) Dinner Broiled trout with butter, sautéed bok choy Many people find that they are not as hungry on the keto diet because of how filling fat can be. But even if you don’t think of yourself as a snacker, you’ll want to keep keto-friendly options on hand (in your purse or backpack and in your office desk) in case hunger strikes. Some nuts, certain meats, olives, and cheese — all high-fat, low-carb eats — are approved. Many companies are getting into the business of the keto diet and are creating their own specialty products that take the guesswork out of macronutrient counting. Some even have tried to mimic favorite snack foods that are typically high in carbs, such as candy, potato chips, and even cookies. It’s important to keep those options to minimum and stick to more whole foods when you snack. Take Chipotle, which now offers the Keto Salad Bowl, complete with carnitas, guacamole, tomatillo red chile salsa, and cheese. And that’s just the beginning. With bunless burger options galore at fast-food chains across the United States, dining out on keto doesn’t have to be rocket science. Still, you might want to do a little research before an upcoming road trip or night out. Same goes if you know you’re not going to have as much time for meal prep on a certain week and know you’ll have to resort to hitting the drive-through. When it comes to ordering, the same general rules you’d use to build keto meals apply: Steer clear of the buns, tortillas, rice, and breaded meats. When in doubt, opt for a salad with nonstarchy veggies, cheese, avocado, and a simple, olive oil–based salad dressing. If you aren’t a salad fan, though, rest assured that you have numerous other options at your disposal. Learn More About Ordering Fast Food on the Keto Diet Get More Book Recommendations for Following the Keto Diet This program targets adults who want to lose weight with keto, aiming to help guide dieters through the process safely. It offers 10 sessions with a healthcare practitioner, as well as support from health coaches, which can help you plan and successfully execute a low-carb diet.
Favorite Keto Lectures and Interviews
Keto Nutrition Dominic D’Agostino, PhD, an associate professor at the University of South Florida in Tampa, runs this website. For a more in-depth and dynamic look into the keto diet (including information on the ketogenic diet and cancer), his appearances on podcasts and lectures are a must — and this page collects all these links.
Favorite Keto Conference
KetoCon Meet up with fellow keto followers, as well as medical professionals and keto lifestyle coaches. Plus, you’ll learn about new products aimed at supporting your keto journey during this three-day event.
Favorite Keto Foundation
The Charlie Foundation for Ketogenic Therapies Started 25 years ago, this foundation focuses on advancing awareness of the ketogenic diet as a medical therapy diet for epilepsy, cancer, autism, ALS, Parkinson’s disease, type 2 diabetes, and traumatic brain injury.
Favorite Keto Diet Calculator
KetoDietCalculator Run by the Charlie Foundation, this calculator can be helpful when you’re using keto as a therapy to help manage a medical condition. The calculator helps estimate calorie needs based on weight, assists in determining a macro ratio and macros needed per meal, and can calculate macro numbers on the basis of meals and snacks you enter into the system. Also takes into account fluids, supplements, and medications.
Favorite Keto App
Senza Free; in-app purchases; ranked 4.8 on iTunes and 4.1 on Android This app counts macros easily and displays them clearly so you can stay on track. It offers a database of keto-approved foods and restaurant items. You can also monitor electrolytes to help yourself potentially avoid the keto flu. If you’re someone who needs to monitor ketones, this app will also track that info.
Favorite Website for Clinical Trials
ClinicalTrials.Gov From the National Institutes of Health, this government website lists all the ongoing and completed trials involving the keto diet. Use it to stay up to date on the potential newest applications of keto, as well as trials that may be currently recruiting for participants in your area. Use this guide, and ideally work with a registered dietitian nutritionist, to develop healthy keto meals and snacks. And if you’re looking to help manage or prevent a health condition, be sure to get clearance from your entire healthcare team before making dramatic changes to your eating habits.
