One enduring buzzword to hit the diet world seems to be “keto” — referring to the high-fat, low-carb ketogenic diet. With claims that you can eat all the fat you want, never feel hungry again, and even boost your athletic performance, the diet promises something for everyone.
But what exactly is the ketogenic diet, and is the weight loss program right for you? Let’s take a closer look before you attempt to make over your eating habits and lifestyle.
What Is the Ketogenic Diet?
What Is the Keto Diet?
How to Follow the Ketogenic Diet
A modified version of the ketogenic diet, which allows you to eat protein more liberally — at 20 to 30 percent of your total calories — with the same carbohydrate restriction, is the more commonly used version of the diet today. Some of the aims of the latest version of the ketogenic diet are weight loss, weight management, and improved athletic performance.
What Is Ketosis?
How Do You Know if You’re in Ketosis?
Many people associate elevated ketones with a diabetic medical emergency known as ketoacidosis, but nutritional ketosis associated with a ketogenic diet and diabetic ketoacidosis are very different conditions.
Ketosis vs. Diabetic Ketoacidosis (DKA)
For people with diabetes, rapidly rising ketone levels can signal a health crisis that requires immediate medical attention. When there is an absence or not enough of the hormone insulin (or the body is too resistant to insulin to allow it to drive glucose into the cells for energy), the body cannot use glucose for fuel. Insulin helps ferry glucose to our cells and muscles for energy. Instead, in this case, the body resorts to burning stored fat for energy through the process of ketosis, leading to a buildup of ketones in the body.As ketones accumulate in the bloodstream of a person with diabetes, they cause the blood to become more acidic, which can lead to the condition known as ketoacidosis. This condition can be fatal and should be treated immediately, as an article published in May 2021 in Endotext points out.
Potential Health Benefits and Risks of the Keto Diet
If you search online for the term “keto diet,” you'll find a lot of health claims associated with the ketogenic diet. But before you give this approach a try, it’s important to know what the science suggests about how it may affect your health. Namely, you'll want to know about potential keto diet dangers.
Risk: You May Suffer Fatigue and Other Symptoms as a Result of the Keto Flu
Risk: You May Experience Constipation if You Don’t Eat Enough Fruits and Veggies
Risk: You Could Develop Dangerous Nutrient Deficiencies
Eliminating food groups can be problematic. “Ketogenic diets are often low in calcium, vitamin D, magnesium, and folic acid, which over time can lead to nutrient deficiencies if the diet is not planned carefully,” adds Marie Spano, RD, a sports performance nutritionist in Atlanta.
RELATED: What Is an Elimination or Exclusion Diet?
Risk: You May Harm Your Heart With the Diet’s Emphasis on Animal Fat and Protein
RELATED: Is the Paleo Diet Good for Heart Health?
Risk: You May Experience Dangerous Low Blood Sugar if You Have Diabetes
Risk: You May Experience Weight Cycling and Negative Effects on Your Metabolism
Outside of physical health changes, one of the biggest concerns of the ketogenic diet may be in long-term adherence. “It’s a very difficult diet to stick to and maintain. Compliance is a challenge because it is so restrictive,” explains Dr. Mohr.
Benefit: You May See Improvements in Your Athletic Performance
Benefit: You Could Lose Weight Fast — but Not Necessarily More Than You’d Lose on Other Diets
But when it comes to weight loss — one of the biggest keto selling points for many individuals — the benefits of the ketogenic diet may not be much different from any other diet plan. “There is no magical weight loss benefit that can be achieved from this diet,” says Spano. “The ketogenic diet may help weight loss in the same way other diets help — by restricting food choices so you eat fewer calories.”
Benefit: You May See Better Blood Glucose Control if You Have Type 2 Diabetes
Learn More About the Possible Benefits and Risks of the Keto Diet
Common Questions & Answers
Is the Keto Diet Right for People With Diabetes?
Plus, because keto hasn't been studied long term, researchers don't know if the diet will result in nutrient deficiencies for those with or without diabetes.
If you're considering trying the keto diet and you have diabetes, it's crucial to consult your diabetes-care team before doing so to make sure it's a safe and effective eating approach for you.
Learn More About How the Keto Diet May Benefit People With Type 2 Diabetes
How to Get Started on the Ketogenic Diet
Here are some other things to know before you try this restrictive eating plan.
Can You Stick With the Carb Restrictions?
It’s important to remember that the goal of any dietary change is to promote a healthy lifestyle, so make sure to select a meal plan you can envision yourself following long term. If you know you will not be able to comply with such stringent carbohydrate restrictions for years to come, the ketogenic diet is most likely not the right choice for you.
What Are the Different Types of Keto Diets?
There are various modifications of the ketogenic diet. The majority of individuals following a ketogenic diet follow the so-called standard ketogenic diet plan, which provides about 10 percent of your total calories from carbohydrates.
Other forms of ketogenic diets include cyclic ketogenic diets, also known as carb cycling, and targeted ketogenic diets, which allow for adjustments to carbohydrate intake around exercise. These modifications are typically implemented by athletes looking to use the ketogenic diet to enhance performance and endurance and not by individuals specifically focused on weight loss.
Generally speaking, if you plan to follow a ketogenic diet, you should aim to consume less than 10 percent of your total calories from carbohydrates per day. The remaining calories should come from 20 to 30 percent protein and 60 to 80 percent fat. That means if you follow a daily 2,000-calorie diet, no more than 200 of your calories (or 50 grams) should come from carbs, while 400 to 600 calories should come from protein and 1,200 to 1,600 should come from fat. (There’s a reason this plan is also called a high-fat, low-carb diet!)
Is Exercise Involved in the Standard Ketogenic Diet?
For endurance athletes, the transition to a ketogenic diet may cut recovery time after training, but for casual exercisers, the transition to the ketogenic diet may make sticking with your fitness routine a challenge at first, the article notes. If you feel your energy levels drop too much when starting the ketogenic diet, slow down your reduction of carbohydrates, and make sure to do it gradually rather than all at once.
What Side Effects Should You Expect?
To prevent side effects such as the keto flu, begin transitioning your meal plan gradually. Start by understanding how many carbohydrates you consume most days. Then begin slowly reducing your carbohydrate intake over a period of a few weeks while gradually increasing your intake of dietary fat to keep your calories the same. You should also make sure to seek guidance from a professional to make sure this plan works for you and your health goals. “See a dietitian and adapt the diet to fit your long-term needs,” Spano recommends.
Learn More About What Beginners Should Know Before Trying the Keto Diet
What to Eat on the Standard Ketogenic Diet
The ketogenic diet is not a commercial meal plan, so there are no costs or membership fees associated with starting this diet. But, depending on your current eating habits, this eating approach may increase your food bill.
Because many processed foods are not considered ketogenic diet friendly, a switch to buying more whole, unprocessed foods may seem expensive, especially with the emphasis on high-fat and protein-rich foods.
In-season, fresh produce, along with frozen vegetables, which can be just as healthy as their fresh counterparts, will help reduce your costs. Although nuts, seeds, and animal proteins such as beef can drive up the grocery bill, bulk buying can help you save on these items as well.
Adding fat-rich foods such as avocado, nuts, and seeds can all make for healthful options that will provide you with unsaturated fats along with beneficial fiber. Most fruits are restricted on this plan — there are exceptions, including avocado — but nonstarchy vegetables such as leafy greens should become a staple of your diet.
Lean proteins such as fish, poultry, and grass-fed beef can be included as a source of protein on this diet.
A List of Acceptable Foods for the Standard Ketogenic Diet
- Nonstarchy vegetables like leafy greens, broccoli, cauliflower, cabbage, peppers, mushrooms, onions, and rhubarb
- Dairy, including eggs and cheese
- Protein like beef, pork, poultry, fish, shellfish, and soybeans
- Nuts and seeds, including walnuts, almonds, pistachios, sunflower seeds, and pumpkin seeds, coconut (in moderation)
- Fats like plant-based oils and butter
- Fruits like avocado, berries (in moderation), and tomatoes
Foods You Should Avoid or Limit on the Ketogenic Diet
- Processed foods like crackers, corn chips, and potato chips
- Sweets, including candy, cookies, brownies, and cake
- Grains of all kinds, including bread, pasta, rice, and quinoa
- High-carb fruits like melons and tropical fruits
- Artificial sweeteners such as Equal and Splenda
A Sample 3-Day Menu for the Standard Ketogenic Diet
- Breakfast: Scrambled eggs with sliced avocado
- Snack: Almond butter on celery
- Lunch: Spinach salad topped with canned tuna, olive oil, and vinegar
- Snack: 1 ounce (oz) string cheese and 1 oz pistachios
- Dinner: Sirloin steak paired with sautéed mushrooms, onions, and cauliflower rice
- Breakfast: Mushroom and cheese omelet with sliced bacon
- Snack: ½ avocado
- Lunch: Chicken stir-fry with peppers, onions, and peanuts sautéed in peanut oil
- Snack: 1 oz Brie cheese with 1 oz walnuts
- Dinner: Salmon fillet with oven-roasted Brussels sprouts
- Breakfast: Keto smoothie made with avocado, full-fat coconut milk, chia seeds, and nut butter
- Snack: Hard-boiled egg
- Lunch: Cheeseburger (without bun) over a bed of lettuce paired with string beans
- Snack: 1 oz almonds
- Dinner: Chicken breast paired with sautéed broccoli
Learn More About What You Can and Can’t Eat on the Keto Diet
What to Expect if You Try the Keto Diet
While the keto diet can lead to rapid weight loss through ketosis, the plan carries some health risks, including:
- Nutritional deficiencies
- Heart harms
- Gastrointestinal issues like constipation, and more.
Because of the health risks involved, experts advise some individuals, such as those with heart disease or individuals who are at a higher risk for it, against trying the keto diet. People with type 2 diabetes should consult their doctor before attempting the keto (or any new) diet.
If you are planning to try the keto diet, be sure to consult your healthcare team and, if possible, a registered dietitian to make sure you meet your nutritional needs on the plan. Working with a professional can help you determine whether you should make adjustments or if you’d be better off avoiding the diet entirely.
Editorial Sources and Fact-Checking
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- Low-Carb Diet: Can It Help You Lose Weight? Mayo Clinic. November 18, 2020.
- Dietary Intake for Adults Aged 20 and Over. National Center for Health Statistics: Centers for Disease Control and Prevention. March 26, 2021.
- Gosmanov A, Gosmanova E, Kitabchi A. Hyperglycemic Crises: Diabetic Ketoacidosis (DKA), and Hyperglycemic Hyperosmolar State (HHS). Endotext. May 19, 2015.
- Constipation: Overview. Mayo Clinic. June 29, 2019.
- Anand S, Hawkes C, Souza R, et al. Food Consumption and Its Impact on Cardiovascular Disease: Importance of Solutions Focused on the Globalized Food System. Journal of the American College of Cardiology. October 2015.
- Heart Disease Risk Factors. Centers for Disease Control and Prevention. December 9, 2019.
- Diabetic Ketoacidosis: Overview. Mayo Clinic. November 11, 2020.
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- Noakes T, Volek J, Phinney S. Low-Carbohydrate Diets for Athletes: What Evidence? British Journal of Sports Medicine. July 2014.
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- Feinman RD, Pogozelski WK, Astrup A, et al. Dietary Carbohydrate Restriction As the First Approach in Diabetes Management: Critical Review and Evidence Base. Nutrition. January 2015.
- Azar S, Beydoun H, Albadri M. Benefits of Ketogenic Diet for Management of Type Two Diabetes: A Review. Journal of Obesity & Eating Disorders. September 2016.
- Paoli A. Ketogenic Diet for Obesity: Friend or Foe? International Journal of Environmental Research and Public Health. February 2014.
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- Choosing Oils for Cooking: A Host of Heart-Healthy Options. Harvard Medical School. March 1, 2019.
- Hall KD, Guo J, Courville AB, et al. Effect of a Plant-Based, Low-Fat Diet Versus an Animal-Based, Ketogenic Diet on Ad Libitum Energy Intake. Nature Medicine. February 2021.
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- Kirkpatrick CF, Bolick JP, Kris-Etherton PM, et al. Review of Current Evidence and Clinical Recommendations on the Effects of Low-Carbohydrate and Very Low Carbohydrate (Including Ketogenic) Diets for the Management of Body Weight and Other Cardiometabolic Risk Factors: A Scientific Statement from the National Lipid Association Nutrition and Lifestyle Task Force. Journal of Clinical Lipidology. September–October 2019.
- Castellana M, Conte E, Cignarelli A, et al. Efficacy and Safety of Very Low Calorie Ketogenic Diet (VLCKD) in Patients With Overweight and Obesity: A Systematic Review and Meta-Analysis. Reviews in Endocrine and Metabolic Disorders. March 2020.
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