The ketogenic diet is a low-carb, high-fat diet. It shares similarities with the Atkins and various other low-carb diets.

The keto diet involves drastically reducing your carbohydrate intake and replacing it with fat. This forces the body into a state of ketosis. This happens when molecules called ketones build up in the bloodstream. It’s a result of eating a low- or no-carb diet.

The diet has gained popularity in recent years thanks to its link to rapid weight loss, ability to help moderate the symptoms of epilepsy among children, and control of blood sugar in those with type 2 diabetes.

But it’s also garnered its fair share of criticism. There are those who believe the keto diet isn’t a sustainable, long-term dietary plan and can do more harm than good. As is the case with most fad diets, there are varying opinions on the subject.

So we’ve gone out into the community and asked medical professionals, fitness experts, and those who follow the keto diet to answer questions most often associated with this hot-button issue.

Leanne Vogel

Healthful Pursuit

What do you eat on a keto diet?

Keto is so much more than what most people typically think. While bacon and eggs are great, I prefer lots of variety from nutrient-dense, alkaline-forming foods. Think quality grass-fed meats and fats that won’t cause inflammation, lots of veggies with a low Glycemic Index like kale, spinach, broccoli, and zucchini, and the occasional strategic use of complex carbohydrates, what I call a “carb up.”

I’ve labeled my approach to the ketogenic diet the Fat Fueled approach. It differs because it focuses on a few things: eating enough, not forcing yourself to fast, eating the right amount of carbohydrates for your individual needs, focusing on whole foods, and not consuming dairy (because it’s inflammatory for most people).

Bio: Leanne is a nutrition educator, host of “The Keto Diet Podcast,” and the author of the national and international best-seller “The Keto Diet: The Complete Guide to a High-Fat Diet.” Her goal is to help you do away with feeling overpowered and controlled by food through providing you with the tools you need to inject your life with happiness, healthfulness, and a whole lot of dietary fat.

Ben Greenfield

Ben Greenfield Fitness

How do I fill the nutritional gaps when on the keto diet?

To fill in notoriously missing nutritional gaps in a ketogenic diet, be sure to cover your bases with the following: potassium and magnesium, lots of dark greens or greens powders, plenty of polyphenols like low-sugar berries and anti-inflammatory herbs, and spices like ginger, garlic, and curcumin.

Bio: In 2013 and 2014, Ben was named as one of the world’s top 100 most influential people in health and fitness by Greatist. By 2015, Ben was coaching the world’s top CEOs, chefs, biohackers, poker players, professional athletes, and tennis, motocross, and endurance competitors — all while advising and investing in top companies in the health, fitness, and nutrition industry. As founder and CEO of Kion, Ben now creates step-by-step solutions, from supplements and fitness gear to coaching and consulting for the world’s hard charging, high achievers — all from his quiet home in Washington state.

Julie Upton

Appetite for Health

Will a keto diet help me lose weight?

Yes, it will. But that doesn’t mean it’s healthy, nor would we recommend that someone follow a keto diet. The problem with the keto eating style is that is restricts carbs to about 40 grams per day (the amount in about 1 1/2 apples), so it’s virtually impossible for people to follow for any sustained period of time. When you remove carbs from your plate, you cut out about 50 percent of the calories in a typical American diet. Essentially, the way keto helps you lose weight is by drastically reducing your calories — no magic involved.

Bio: Julie Upton, MS, RD, is a communications expert specializing in nutrition, fitness, and health. Upton is a nationally recognized journalist who’s written articles for national newspapers, magazines, and e-media, including The New York Times, Shape, and The Huffington Post. She’s a frequent guest on national and local television and radio stations. She’s been interviewed on NBC’s “Today” show, “CBS Evening News,” and “ABC World News Tonight.” She co-produces “Appetite for Health,” a weekly nutrition news segment that airs nationally and writes for the companion website, AppForHealth.

Robb Wolf

Can you do keto if you don’t do dairy?

Yes. While dairy is one of the major sources of fat, there are still plenty of other options to fill your fat needs. Personally, I cannot handle dairy products — except for goat or sheep’s milk — and I’m able to stay in ketosis without it. I strongly encourage getting your fat from whole, real foods, such as meat, oils, avocado, olives, and nuts. As a side note, you do have to be a little more careful when it comes to nuts — some have a much higher carb count, so it’s easy to accidentally overdo carbs.

For protein, it’s important to choose something with large amounts of fat relative to protein to simplify things, since you won’t need to add as much fat to hit your macro and calorie goals, like fish.

Bio: Robb Wolf, the New York Times’ best-selling author of “The Paleo Solution” and “Wired to Eat,” is a former research biochemist and a leading expert in nutrition, health, and wellness. Wolf has transformed the lives of hundreds of thousands of people around the world via his top-ranked iTunes podcast, books, and online course.

Andreas Eenfeldt, MD

Diet Doctor

Is ketosis good for individuals with type 2 diabetes?

Yes. A ketogenic diet can even potentially reverse type 2 diabetes, normalizing blood sugar, sometimes even making it possible for people to get off all diabetes medications and still achieve fully normal blood sugars. It can also improve blood pressure.

The main potential risk to be aware of is that people can rapidly become too healthy for their diabetes drugs (primarily insulin) and blood pressure drugs. This may require doses to be reduced or eliminated, sometimes as early as day one on the diet, to avoid overdosing.

Bio: Dr. Andreas Eenfeldt is a Swedish medical doctor who specializes in family medicine. Dr. Eenfeldt spent 12 years working as a doctor, and eight of those years as a family physician, treating people with low-carb, high-fat diets. During that time, he witnessed tremendous success for people with obesity and type 2 diabetes. But despite that, helping one person at a time couldn’t change the status quo, so in 2015, he quit. He now runs the health site Diet Doctor together with 17 co-workers. The site is completely free from ads, product sales, or industry sponsorship. Instead, it’s fully funded by the people via an optional membership.

I Quit Sugar Nutrition Team

I Quit Sugar

What are the symptoms of ketosis?

In the early stages of ketosis, it’s common to experience a number of symptoms. This can include (but isn’t limited to) decreased energy levels, irregular sleep patterns, constipation, frequent urination, mood changes, and halitosis. However, symptoms can also vary depending on individual factors, such as the presence of autoimmune diseases, diabetes, and stage of life.

Bio: The I Quit Sugar: 8-Week Program helps people quit sugar by recalibrating their taste buds and resetting their appetite. This means they’re no longer a slave to those sweet cravings and can, instead, listen to their body as it tells you what foods makes them feel good.

Matt & Megha

KetoConnect

I’m concerned about incorporating so much fat into my diet and whether I’ll be able to do so on a daily basis. What should I do?

Making the switch to eating the majority of your calories from fat can be a really hard thing to do after we’ve become accustomed to seeing low-fat products everywhere and being told we should avoid fat. However, once you start incorporating more fat into your diet, you’ll be able to connect the eating fat to feeling good and more energetic. The benefits are almost immediate for many people.

Getting in 75 percent of your calories from fat when you’re not used to it can be very difficult, but there are several ways to do this. The best advice we can give you is to plan ahead. You can either plan out one day in advance or even meal prep for the week to stay on track and accountable. Some great food options for high fat are bulletproof coffee or tea, which is adding butter or oil to your hot drinks. You can also make “fat bombs” (a combination of ingredients such as butter, nuts, unsweetened chocolate, and coconut oil) for a sweet treat and a quick way to boost your fat intake for the day.

Bio: Matt and Megha are the faces behind the ketogenic food blog KetoConnect and YouTube channel where they share low-carb recipes and videos on how to make them. They also make informational videos to educate keto beginners and people looking to expand their knowledge of the keto diet.

Beth Zupec-Kania

Ketogenic Therapies LLC

Can I go on and off a ketogenic diet?

I don’t advise that. A boost in carbohydrates can cause a surge in insulin that can lead to a reaction called “reactive hypoglycemia.” It can make you feel awful.

Bio: Beth A. Zupec-Kania, RDN, CD, owner of Ketogenic Therapies LLC, has specialized in ketogenic therapies since 1991. She began her career as clinical hospital dietitian and has been a private consultant since 2006. Beth received her Bachelor of Science degree in nutritional sciences at the University of Wisconsin, Madison. She consults internationally for individuals with autism, epilepsy, mitochondrial and metabolic disorders, migraine headaches, rare genetic disorders, various cancers, and Parkinson’s disease. Ms. Zupec-Kania also serves as a consultant to the Charlie Foundation for Ketogenic Therapies.

Libby Jenkinson

Ditch the Carbs

Why aren’t I losing weight on a low-carb or keto diet?

Weight loss isn’t always linear, and it varies person to person. When it comes to the keto diet, we like to encourage people to focus on how they feel day to day as opposed to the numbers. There are so many incredible benefits to the diet, and you’re allowing your body to heal. That process takes time, and by healing your body on the inside (think hormone regulation, digestive health, inflammation), the weight will more easily and naturally come off.

Bio: Libby Jenkinson is a registered pharmacist and mother of three children. She’s the founder of Ditch the Carbs, a leading low-carb website in New Zealand and Australia that offers recipes, articles, and support to those looking to make healthy changes to their diets.

Justin Mares

Kettle & Fire

What are the most common mistakes people make on a keto diet?

The first is not getting enough salts (sodium, potassium, and magnesium). While we typically get lots of sodium thanks to processed foods, most people find that when they go keto and cut out processed foods, they’re actually low on sodium. You might not think of low sodium as a problem, but it usually results in fatigue and cravings, so make sure you get sufficient amounts.

Not eating enough greens is also a common mistake. One of the keys of a ketogenic diet is to eat fewer carbohydrates. Many people interpret this to mean avoiding all vegetables. Please don’t do that! For good gut health and to ensure you get plenty of vitamins and minerals, it’s important to keep eating a lot of vegetables. There are many ways to get more veggies into your diet. Salads, sautés, and green smoothies are all easy and quick to make.

Finally, not exercising. Exercise is one of the components of a healthy lifestyle that many of us skip when we’re trying out a new diet. It can be mentally hard to stick to keto during the first few weeks, and that makes going to the gym more challenging. However, it’s good to try and do some exercise if you can manage it. It’ll often help you get keto-adapted faster and help with fat loss.

Bio: Justin Mares is the co-founder and CEO of Kettle & Fire, a company that offers organic, grass-fed, and paleo-friendly bone broths.

Before you begin a keto diet

Talk to your doctor before beginning a keto diet to ensure it’s right for you and won’t worsen any health conditions you may have. They can work with you and help monitor any negative effects.

Some side effects to keep in mind and talk to your doctor about include: