The Atkins diet may be a distant memory for a lot of us, but the thing about once-popular fads? They inevitably reemerge. And along with low-rise jeans of the early 2000s, another craze making a comeback is the low carb lifestyle — this time, in the form of the ketogenic diet.

As with any trend, if you’re going to jump on board, you’ve got to know how to do it right. That’s where we come in to help you with this all-you-need-to-know guide to killing it at keto.

Although the ketogenic diet is more popular than ever, its origins go back to 1923, when it was founded at the Mayo Clinic to treat epilepsy.Masood W, et al. (2019). Ketogenic diet. https://www.ncbi.nlm.nih.gov/books/NBK499830/

The diet calls for a high fat, low carb approach to eating, with a breakdown of macronutrients that generally falls in the realm of 55 to 60 percent fat, 30 to 35 percent protein, and 5 to 10 percent carbohydrates.

So, why so low carb? Glad you asked. When we eat a balanced diet, our bodies naturally break down carbohydrates into glucose as our preferred source of fuel. (You may remember at some point being advised to carb-load before a race, for example.)

But when we don’t feed our cells with carbs to convert to glucose, the body turns to fat for fuel instead. When the liver converts fat, it produces an acid byproduct called ketones that our cells can use as energy.Chang CK, et al. (2017). Low-carbohydrate-high-fat diet: Can it help exercise performance? DOI: 10.1515/hukin-2017-0025

This is better known as being in a state of ketosis.

If you’ve hopped on the keto bandwagon, you’re probably on the lookout for signs of ketosis. It may sound a little freaky, but here’s what you can look out for.

First, a lot of people can detect when they’re in ketosis just by the smell of their breath.Anderson JC, et al. (2015). Measuring breath acetone for monitoring fat loss: Review. DOI: 10.1002/oby.21242 And guys, it ain’t great (like, no amount of brushing or flossing is gonna help).

Basically, it boils down to this. Since one of the by-products of ketosis is acetone, and it can’t be used by the body, it’s excreted through our breath, sweat, and urine. Fun stuff.

A more accurate test, however, is to use ketone detection strips. These strips should come with an easy-to-follow color guide for detecting specific levels of ketones in the urine. You can usually expect them to change from a neutral beige to a shade of red in a positive ketosis test.

But remember, ketosis should only be the goal if you’re going hard on the fats. Not sure where to start? Try some of these killer keto recipes when you’re looking for a meal that’s not just a hella ton of avocado in a bowl.

Whether it’s because of the benefits of eating high fat and low carb, or because you feel justified in eating cheese all day long, keto has officially become one of the hottest diets around. Here are a few reasons why.

Weight loss

It may not be that easy to cut out all the carbs, but emerging research suggests that — surprise! — eating fat can actually help burn fat.Kossoff EH, et al. (2014). Ketogenic diets: New advances for metabolism-based therapies. DOI: 10.1097/WCO.0b013e3283515e4a So, for anyone trying to lose weight, you may find it worth the carb cut.

Beyond weight loss, recent research has found some other serious health benefits of keto that may impact your life later on. Let’s take a look at what the research has to say.

Reduced appetite

OK, so this one goes hand-in-hand with weight loss, but the high fat, moderate protein nature of the diet ensures that you’re more satiated by the food you’re eating and aren’t filling up on empty carbohydrates that do nothing for your hunger.Paoli A, et al. (2013). Beyond weight loss: a review of the therapeutic uses of very-low-carbohydrate (ketogenic) diets. DOI: 10.1038/ejcn.2013.116

The great thing about keto diet is that most dieters report not feeling hungry at all,Gibson AA, et al. (2015). Do ketogenic diets really suppress appetite? A systematic review and meta-analysis. DOI: 10.1111/obr.12230 likely because ketosis tends to suppress the hunger hormone, ghrelin, which helps tame our hangry monster within.Sumithran P, et al. (2013). Ketosis and appetite-mediating nutrients and hormones after weight loss. DOI: 10.1038/ejcn.2013.90

When you combine a satiating diet with the fact that you’re just cutting out a lot of foods, it makes perfect sense then that you’ll lose weight. Pass the cheese, please.

Better blood sugar levels

Research shows that by restricting the amount of glucose coming into the body, the keto diet has the potential to control and improve insulin and blood sugar levels.Paoli A, et al. (2013). Beyond weight loss: a review of the therapeutic uses of very-low-carbohydrate (ketogenic) diets. DOI: 10.1038/ejcn.2013.116 This makes it a promising option for those with type 2 diabetes.

A stronger ticker

Wait, what?! How could a diet rich in meat, butter, and cheese do anything but increase the chances of a heart attack? Well, the tables might be turning in defense of fat.

Yup, you read that right. Although we’ve been lectured for years on the negative effects of too much fat on cardiovascular health, there is some recent evidence that ketosis can actually have positive effects on blood lipid and cholesterol levels, though more research is needed.Kosinksi C, et al. (2017). Effects of ketogenic diets on cardiovascular risk factors: Evidence from animal and human studies. DOI: 10.3390/nu9050517

Curbed epilepsy

Recent research confirms that the keto founder, Dr. Russell Wilder, had the right idea when it comes to treating epilepsy.Suvasini S, et al. (2014). The ketogenic diet and other dietary treatments for refractory epilepsy in children. DOI: 10.4103/0972-2327.138471

It turns out that, in a ketosis states, neurons in the brain are stabilized and this controls the frequency of epileptic seizures. More research is needed to determine why, but it looks like there could be a link to increased GABA neurotransmitters in the brain.Meria ID, et al. (2019). Ketogenic diet and epilepsy: What we know so far. DOI: 10.3389/fnins.2019.00005

May prevent cognitive decline

Studies show that a ketogenic diet may enhance mitochondrial activity and reduce oxidative stress, making it effective in the prevention of inflammatory diseases like Alzheimer’s and Parkinson’s.Taylor MK, et al. (2018). Feasibility and efficacy data from a ketogenic diet intervention in Alzheimer’s disease. DOI: 10.1016/j.trci.2017.11.002

Improved MS symptoms

While research in this area is still in its infancy, an exciting 2016 study found that the keto diet helped improve the quality of life, physical health, and mental health of patients living with multiple sclerosis.Choi IY, et al. (2016). A diet mimicking fasting promotes regeneration and reduces autoimmunity and multiple sclerosis symptoms. DOI: 10.1016/j.celrep.2016.05.009

While there are parallels between the keto diet and the Atkins diet, what sets keto apart is that, unlike the latter, it doesn’t give an unlimited pass to protein consumption.

Excess protein, like carbohydrates, gets converted to glucose — something we don’t want much of in order to reach ketosis faster. So, what can you eat?

Veggies

Unlike most other diets, it’s not “all veggies go” on keto. There’s really no such thing as a bad vegetable, but some are higher in carbs than others, going against keto principles.

Instead of starchy root veggies, stick to those that grow above ground, plus high fiber ones. Here’s a non-exhaustive list:

  • artichokes
  • asparagus
  • bell peppers
  • broccoli
  • cabbage
  • cauliflower
  • celery
  • cucumbers
  • fennel
  • leafy greens
  • mushrooms
  • onions
  • sauerkraut
  • tomatoes
  • zucchini

Fruits

Most fruits are too high in sugar to be acceptable for the keto diet, but there are some you can enjoy in moderation. Stick to small servings and try to limit your intake to one serving a day.

  • Avocados. High in fat and low in sugar, this is actually a fruit you can eat often on the keto diet.
  • Berries. Strawberries, blueberries, raspberries, blackberries are all okay, but stick to a small serving size; just 1 cup of blueberries could have 20 grams of carbs.
  • Lemons. Not that you’re actually chomping into a lemon as a snack, but just know that you can if the urge happens to strike. Or simply use it to flavor meals and beverages.

Herbs and spices

They’re perfect for adding tons of flavor to your food without relying on condiments (ahem, refined sugar).

Go beyond the usual salt and pepper and season your meals generously with cumin and cinnamon, basil and oregano, parsley and sage, paprika and turmeric, garlic and ginger… you get the idea.

Dairy

Always go full fat.

  • Cheeses. Cheddar, Swiss, cottage, gouda, ricotta… drooling yet?
  • Yogurt. Full fat, plain, and unsweetened is the way to go.
  • Sour cream. To dollop on low carb tacos or even use in keto-friendly baking.
  • Heavy cream. Add a few spoonfuls to your coffee or thicken curries and soups with it.

Proteins

Fat is the foremost way to keep your body in ketosis. But protein is still a crucial part of the keto diet because it enables gluconeogenesis, a process that fuels tissue and maintains glucose levels where ketones can’t.Masood W, et al. (2019). Ketogenic diet. https://www.ncbi.nlm.nih.gov/books/NBK499830/

Include these on your plate to get your fix:

  • Poultry. Turkey works but, ideally, you want fattier cuts of chicken, like thighs or wings.
  • Beef. Choose higher fat cuts like steaks over lean ground beef.
  • Pork. Oh, hey, pork belly low carb tacos!
  • Seafood. Especially oily fish like salmon, mackerel, sardines, and tuna.
  • Eggs. No more “egg white-only” omelets. Embrace the yolk, which is where all of the fat and nutrients live.

Fats and oils

The cornerstone of the keto diet, fat is the macronutrient to really hone in on here, but make sure you’re feasting on the right fats. Recommended fats on the keto diet include:

Monounsaturated fats (MUFAs)

  • Certain oils. Avocado, walnut, olive, and flaxseed are optimal.
  • Avocados. Worth a second mention.
  • Olives. Pair ’em with cheese for a keto snack plate.
  • Nuts and nut products. Just make sure the nuts haven’t been roasted in vegetable oil (oh, and no peanuts).

Saturated fats

  • Cow’s milk butter. It makes everything better.
  • Coconut products. Oil, butter, milk, cream, and shredded coconut to name a few.
  • Ghee. Cook just about anything in this delicious clarified butter.
  • Lard. Yes, bacon. Need we say more?

Medium-Chain Triglycerides (MCTs)

With their ability to digest quickly and promote ketosis, MCTs are a super-popular addition on the keto diet.Liu YM, et al. (2013). Medium-chain triglyceride ketogenic diet, an effective treatment for drug-resistant epilepsy and a comparison with other ketogenic diets. DOI: 10.4103/2319-4170.107154

Coconut oil contains MCTs, but the pure stuff is usually available in supplement form as oils or powders. Add them to your coffee or drizzle onto food.

A note on polyunsaturated fats

While polyunsaturated fats are conventionally categorized as the good-for-you kind, the keto diet does warn of the inflammatory effects of omega-6 polyunsaturated fats in vegetable oils and margarine.

Be sure to balance them out with moderate quantities of omega-3 polyunsaturated fats, like fatty fish.

Other keto-friendly ingredients

  • Nondairy milk. Coconut is best (fat, fat, and more fat), but don’t rule out unsweetened almond, cashew, and hemp milk too.
  • Bone broth. When you need something warm but can’t have the caramel macchiato, go for this instead.
  • Some sweeteners. Sugar is totally taboo, but there are certain ingredients that are keto-approved to sweeten things up, like stevia, erythritol, and monk fruit — all in moderation, of course.

Grains

Bread, rice, pasta, and oats are all no-no’s. So are couscous, farro, barley, and bulgur. Even gluten-free grains, including quinoa, polenta, cornmeal, and millet are off the table.

Legumes and beans

While they’re high in fiber and provide great nutrients, they’re too high in carbohydrates to suit the keto diet.

Low fat and processed dairy products

This is not the diet for light cream cheese or skimmed milk. In fact, milk should be used sparingly, since you don’t want to be consuming too many of those milk sugars.

Stick to a splash in plain coffee rather than a full-on cappuccino.

Starchy vegetables

Starch = carbs. Carbs = off-limits. Might as well take beets, brussels sprouts, butternut squash, carrots, corn, parsnips, potatoes, peas, and pumpkin off your grocery list.

High sugar fruits and juices

Fruit can be a refreshing palate cleanser when you’re eating so many other richer foods, but most varieties are simply too high in sugar to support ketosis, including apples, bananas, grapes, mangos, and pears.

As for juices, well, that’s also off-limits. It’s like drinking liquid sugar.

Dried fruit

Even the unsweetened dried apricots, raisins, dates, and prunes have way too much natural sugar to be kosher for keto.

Any and all sugar

Whether it’s added or naturally occurring, sugar must be pretty much eliminated. Don’t forget, added sugars even hide in condiments like ketchup, teriyaki sauce, and relish, so read ingredient labels carefully.

Processed or packaged foods

They’re usually hotbeds of hidden sugar, trans fats, preservatives, and other very non-keto ingredients.

Peanuts

And yes, that includes peanut butter. (So sorry.) Although peanuts are high in fat, they’re also technically legumes and higher in carbohydrates than other nuts.

Still, it’s up to you. Some keto eaters don’t see an issue with eating them in small amounts, while others take a strict stance against them.

Soy

Tofu is a low carb food, yet commercially available soy products like soymilk and soybean oil tend to be made with highly processed soybeans, and anything highly processed is forbidden on the keto diet.

Vegetarians and vegans going keto could use tofu as a source of protein, but if you don’t have those restrictions, stick to meat, seafood, and eggs.

Alcohol

Most alcoholic drinks do contain sugar, and sugar means carbohydrates. It’s probably a better idea to fill your carb quota with vegetables, which offer more fiber and nutrients.

If you really need to take the edge off, stick to spirits served with unsweetened club soda.

Condiments

It bears repeating: You’d be unpleasantly surprised by how many condiments, from barbecue sauce to sriracha to even some types of mayonnaise, contain sugar.

The keto diet is notoriously difficult to stick to, in large part because it’s viewed as so restrictive. In order to set yourself up for success, here are some tips to nudge in the right direction.

Choose the right fats

At first glance, the keto diet can seem like an excuse to go totally nuts on all the fats. But it’s not just about quantity — consuming quality fat matters just as much, if not more.

Be discerning about what types of fat you’re putting in your body, focusing foremost on monounsaturated fats and MCTs, good amounts of saturated fats, and moderate portions of polyunsaturated fats.

Don’t go overboard on the protein

Between the dairy, the meat, and the eggs, this high fat diet can inadvertently turn into a high protein one too.

While protein is a key part of the equation, much of it can distract the body into producing glucose rather than going into ketosis. Keep your protein portions in check and keep some (not a ton of) greens on your plate.

Stay organized

Whether it’s ensuring that you’re hitting the right ratio of fats, proteins, and carbs, or having a keto-friendly meal on the table every night, take advantage of the many resources available to set yourself up for success.

Be mindful of electrolytes and fiber

As you cut the carbs, your body no longer stores as much water as it did when it had a greater glycogen supply. Stay hydrated with water and using both food and supplements to keep your electrolyte count high.

Same goes for fiber — don’t skip out on digestion-aiding, low carb vegetables just because you’re too busy enjoying all the cheese. Otherwise you may get a little, ahem, blocked up.

Give your pantry a makeover

If you’ve still got chips, cookies, bread, and soda in the house, there’s a chance temptation could win over. And just a handful or two of pretzels, and you could totally derail your efforts to put your body into ketosis.

There isn’t much wiggle room on the keto diet, which means there isn’t much room in your house for any food that isn’t keto-friendly.

Get rid of whatever doesn’t make the cut and replace it with whatever does so that you still have plenty to eat.

Try intermittent fasting

Let’s be clear, this does not mean starving yourself. But research has shown that going for longer periods between meals can actually help to put your body in intermittent ketosis, which, in turn, has an appetite-suppressing effect.Zilberter T, et al. (2014). Breakfast: To skip or not to skip? DOI: 10.3389/fpubh.2014.00059

If you’re already comfortable eating the keto way, try fasting between the hours of, say, 7 p.m. and noon the next day (keep drinking water, though!) to take things one step further.

Exercise patience

We all may be used to instant gratification these days, but remember that you’re a human, not a robot. Your body won’t go into ketosis after just one day of eating no bread and all bacon.

Typically, it takes a few weeks to adapt to the high fat lifestyle, and the adjustment period could include bloating or the keto flu. Know that it’s normal and don’t get discouraged — you got this!

Going keto may be the trend of the hour, but not everyone is cut out for the diet’s intense, high fat regimen.

Achieving ketosis can come with some gnarly side effects known as keto flu, a collection of symptoms ranging from headaches, mood changes, and nausea, to fatigue, insomnia, constipation, and bad breath.

While these are actually all part of getting to ketosis, if the symptoms are especially severe, you may decide the diet isn’t quite your cup of tea.

What’s more, a severely low carb diet may not be optimal as a long-term lifestyle, as its restrictive nature can lead to deficiencies of vitamins and minerals that can compromise bone and gastrointestinal health.Masood W, et al. (2019). Ketogenic diet. https://www.ncbi.nlm.nih.gov/books/NBK499830/

In addition, long-term research on the keto diet is lacking. And often, when the weight returns, it’s more pounds added on than the weight loss itself. This yo-yo style of dieting is linked to increased risk of mortality.

Many health professionals believe there is an increased risk for heart disease on the keto diet, despite research that disputes this. The diet may also cause low blood pressure, constipation, kidney stones, and eating disorders.

The keto diet is not safe for many preexisting medical conditions, so please consult a doctor to make your transition to and from the keto diet as safe as possible. Always be mindful of your body’s reactions in the process.

If adhering to the high fat, low carb thing is doing wonders for your energy and health, great!

But remember: Just because your BFF is a die-hard keto advocate it doesn’t mean that you have to be too, if it’s not working out as well for you.

Your physiology, lifestyle, and mental well-being may respond best to a diet that includes all macronutrients and the occasional frosted cupcake — and that’s totally fine. Do what’s best for you.