For a beat there, the ketogenic diet was everywhere.
Lebron, Tebow, Kardashian—you name the headline-maker and they were likely working their way to or living in ketosis. It was all Joe Rogan ever talked about. Chipotle popped in to offer something called a keto “Lifestyle Bowl” on their menu. Keto even supported the continuance of at least one member of the original Jersey Shore cast.
And for a diet that came from bizarre and mysterious origins, you can’t help but be in awe of its staying power. Is keto as trendy as it once was? Probably not. But you likely still have friends who swear by the bread-free, butter-heavy diet.
The foundations of the ketogenic diet haven’t changed: eat a fat-and-protein-rich diet that’s ultra-low in carbs and you’ll enter into “ketosis,” a state where your body burns fat as its primary fuel source.
But what has changed is that we now have perspective on the diet. And, with that perspective, nutrition experts everywhere are breathing a sigh of relief.
Sure, the keto diet is known to deliver quick weight loss results at the beginning. But those who love eating nothing but bacon, cheese, and avocado all day might be disappointed to learn that researchers have yet to prove that keto has any lasting health benefits for the average person, and some worry about the potential health risks of consuming so much fat and so little carbohydrate. What’s more, the research is pretty clear that keto isn’t any more effective for long-term weight loss than other diets out there.
So, in short, keto faced a reality check. If you’re thinking about trying keto and want to determine if it’s worth sacrificing carbs, here’s a healthy dose of that perspective.
What is ketosis?
Ketogenesis has existed as long as humans have.
If you eat a very low amount of carbohydrates, you starve your brain of glucose, the organ’s main fuel source. Your body still needs fuel to function, so your brain flips the switch to tap into your reserve of ketones, which are compounds the liver creates from fat when blood insulin is low. This process is known as ketosis: It’s like when a hybrid car runs out of gas and reverts to pure electricity.
There’s nothing inherently magical about ketones. In fact, you already have them in your body. “Your liver produces ketones all the time, but the rate depends on carbohydrate and protein intake,” says Jeff Volek, Ph.D., R.D., a professor of human sciences at Ohio State University.
When the majority of your diet is made up of carbs and protein—as the average American diet is—ketogenesis (the process of producing ketones) slows. Replacing carbs and protein with fat will put your body into ketosis, thus ramping up ketone production. Essentially, you’ll burn fat instead of carbs for energy. Ketosis is not instantaneous, and the process takes about three days to induce—often with some side effects during the transitioning stages. (More on those later!)
What can you eat on the keto diet?
To understand which foods you should and which you should avoid on the keto diet, you have to first consider three key nutrients: fat, protein, and carbohydrates.
A ketogenic diet generally requires that fat comprise 60 to 80 percent of your total calories. Protein take up about 20 percent, while the remaining 10 percent comes from carbs. Proponents of a ketogenic diet often recommend limiting your carb intake between 20 to 30 grams per day in order to maintain ketosis. For perspective, that’s the equivalent of about half a medium bagel.
Yes, that all. Half a medium bagel.
And remember, carbs aren’t just present in processed foods; a cup of chopped broccoli has 6 grams of carbs, a cup of chopped carrots has 12 grams, and a cup of Brussels sprouts has 8 grams. In other words, eating the recommended five servings of vegetables per day (because fruits, which are higher in carbs, are pretty much off the table) will probably put you at your max carb allowance.
If this sounds like the Atkins Diet from the 1990s, it’s close, but “ketogenic diets tend to be more severe in carb restriction and have a more moderate protein restriction,” says Spencer Nadolsky, D.O., author of The Fat Loss Prescription.
Though you can eat bacon on a ketogenic diet, the rest of the spectrum is limited. Starchy vegetables like potatoes, corn, and squash are too high in carbs. Same with most fruits. Milk, beans, rice, pasta, bread: nope.
To stay as healthy as possible, keto dieters should eat plenty of low-carb vegetables like red bell pepper, kale and cauliflower. These vegetables contain important micronutrients (AKA vitamins and minerals), as well as fiber, which is linked to a lower risk of heart disease, diabetes, and cancer.
The rules of keto impact more than just mealtime, too, since juices, sodas, and alcohol will knock you out of ketosis.
So what does a typical day of eating look on the ketogenic diet?
Sample keto meal plan
- Breakfast: 4 eggs, 1/2 avocado, 1 to 2 Tbsp olive oil
- Lunch: 4 oz baked salmon with 1 Tbsp olive oil, 1/2 bunch asparagus with 1 to 2 Tbsp butter
- Dinner: Rib-eye steak, 2 cups spinach with coconut oil, 2 oz macadamia nuts
Most men consume nearly half of their calories from carbs, according to the Centers for Disease Control and Prevention. And that’s not a bad thing; it’s actually within the range of what the Dietary Guidelines for Americans recommend for optimal health. So, it goes without saying that cutting your intake to less than 10 percent will be a challenge, and may pose some risks.
We’ll get into those a little later, but, first, the ketogenic does have some benefits that are worth highlighting.
How do you know if you’re in ketosis?
Sure, eating bacon and cheese may sound like a dream but achieving ketosis isn’t easy, says Melanie Boehmer, a registered dietitian at Lenox Hill Hospital.
“Sometimes people try and teeter into it and they won’t lower their carbohydrates enough,” Boehmer says. She recommends eating no more than 20 to 30 grams of carbohydrates per day to maintain the ketogenic state.
Often people think they can eat unlimited amounts of meat on the diet, but that isn’t true. Consuming too much protein will also decrease ketone levels.
Cheat days, even if they are rare, and drinking alcohol can take you out of ketosis, too.
You can determine whether you’re actually in ketosis by purchasing an over-the-counter test. However, they’re not always accurate, warns Ginger Hultin, M.S., R.D.N., spokesperson for the Academy of Nutrition and Dietetics.
“They sell testing strips for urine, though those can get false reads for a number of reasons, like hydration levels,” she previously told Men’s Health.
So, in short, it’s kind of tough to tell. You just have to stick to your macros and hope the number on the scale drops.
What are the benefits of the keto diet?
Well, you can lose weight on keto. And maintaining a healthy weight can reduce the risk of and alleviate symptoms related to heart disease, diabetes, and a whole host of other challenging conditions.
When it comes to weight loss, “there is no question that ketosis does work in the short term,” Konstantinos Spaniolas, M.D., associate director of the Stony Brook Metabolic and Bariatric Weight Loss Center in New York.
Anecdotally, plenty of men have told Men’s Health that the keto diet helped them lose large amounts of weight. According to Spaniolas, keto helps with weight loss by reducing cravings.
Some studies show that keto may lower blood sugar for people with type 2 diabetes, but there is not enough long-term research to determine whether it’s safe and effective for diabetics.
Also, side note, although studies have shown that the keto diet can reduce seizures for children with epilepsy, there is no evidence indicating that keto helps with other brain disorders or improves mental cognition, according to Harvard Health Publishing.
So, in the short term, yes, a keto diet can help you lose weight, which may reduce your risk of disease—but more indirectly than directly. But what about in the long term?
Does the keto diet work for long-term weight loss?
It’s still too soon to tell. In fact, the rapid weight loss which occurs at the start of a keto diet may not be fat loss at all.
“Early weight loss at the beginning of the Keto diet is likely related to fluctuations in fluid,” says Ashley Harpst, R.D., a sports dietitian and the owner of Go For the Gold Nutrition in San Diego. “Three to four ounces of water is retained for every 1 gram of carbohydrate stored as glycogen in the muscles to use for energy.” So, as your glycogen stores are depleted and you enter ketosis, there’s less water in your body as well.
There’s also no long-term data on ketogenic diets versus other diets. In a 2015 Italian study, those on a ketosis diet lost 26 pounds in three months. About half of the participants stayed on the diet for a year but lost little additional weight in the next nine months. People in a 2014 Spanish study who followed a very-low-calorie ketogenic diet lost an average of 44 pounds in a year—but a third of them dropped out, possibly because it was too hard to maintain.
Another study, published in 2020 in The BMJ, analyzed the results from 121 previously conducted clinical trials that looked at the effectiveness of various diets (low-fat, low-carb, low-calorie, etc.) for weight loss and lowering markers of cardiovascular disease risk, like blood pressure and LDL cholesterol. Based on data from nearly 22,000 adults, the researchers found that while all of these diets led to weight loss and improvements in cardiovascular health markers in the first six months, virtually all of those benefits had disappeared at the one year mark.
The bottom line: Keto (and any other diet) may lead to weight loss and improved health in the first several months, but even if you’re able to stay on the diet for longer, those benefits will likely disappear after about a year.
Do ketone supplements work?
While it is possible to elevate your ketones by taking them, “without the low-carb stimulus, there is no net increase in ketone production, no decrease in insulin, and no net increase in fat oxidation,” says Volek.
So don’t trust trainers or “body hackers” who say that you can induce ketosis quickly via a pill, powder, or potion—without changing your diet.
What are the side effects of the keto diet?
There are a few. Let’s hit them one at a time.
People who begin the diet often develop “Keto Flu,” as their bodies get accustomed to eating fewer carbs. During this time you may experience headaches, nausea, fogginess, muscle cramps and fatigue. Symptoms last about a week, but staying hydrated and getting ample sleep will help with cramps and exhaustion.
Aside from Keto Flu, you may notice a few other unpleasant side effects. Acetone—yes, the ingredient in nail polish remover—is one of the compounds found in ketones, so your breath may be stinkier than normal. Pooping may be difficult since cutting carbs will lower fiber intake, but a fiber supplement will help keep you regular.
There’s also the risk of nutrient deficiencies when you’re on the keto diet. “An individual who cuts out whole grains may become deficient in vitamin B1 (thiamine) and B3 (niacin),” Harpst says.
These essential vitamins are added to grain products through fortification, as it’s tough to eat enough of them through food alone, and deficiencies can lead to adverse health effects. Iron and vitamin B9 (folate) are also added to grains, and while it’s relatively easy to get enough iron by eating animal products, eliminating grains can lead to folate deficiencies, as well. (This is particularly concerning for women who may become pregnant, as folate is essential for neural tube development in the first month of pregnancy, before most women even realize they’re expecting.)
And, while there’s not enough long-term research on keto diets specifically, a 2021 review published in Frontiers in Nutrition concluded that foods and nutrients typically consumed at higher than average levels on the keto diet (namely red meat, processed meat, and saturated fat) are linked to an increased risk of kidney disease, heart disease, cancer, diabetes and Alzheimers, whereas restricted foods like fruits, vegetables, legumes, and whole grains are associated with lowered risk of these same conditions. “Current evidence suggests that for most individuals, the risks of such diets outweigh the benefits,” the authors state.
Is the ketogenic diet for you?
This may sound like a cop out, but the best diet is the one you stick with. For Volek, who’s been following an ultra-low-carb diet for two decades, it works.
If you can’t stick to it, then it probably won’t.
“This is the problem I have with all of these fad diets,” registered dietitian Andy Yurechko, M.S., R.D., of Augusta University Medical Center in Georgia, previously told Men’s Health. “A healthier type of diet is something you can do every day of your life.”
Since maintaining ketosis requires strict carb counting, this diet works best for people who are diligent. And, it’s probably not a good idea for athletes or avid gym-goers to do the keto diet long-term.
“There is no conclusive research to support any athletic performance benefit [of keto],” Harpst says. “Research continues to show that training on a low carb diet impairs intensity and decreases endurance, recovery and cognitive function.”
It can also impair muscle strength, she says, since carbohydrates are muscle’s preferred energy source during workouts, and because muscle synthesis (AKA, repairing and building muscle in order to get stronger) requires both protein and carbohydrates.
Keto diet tips
Still, there are a few healthy habits from the keto diet that are easy to adopt:
Eat fewer processed carbs
Instead of thinking about the total carbs you’re eating, assess what those carbs provide to you. Do the majority of your carbs come from fruits, vegetables, whole grains, and legumes, all of which deliver loads of and health-supporting fiber and antioxidants? Fantastic. Or are you consuming them mostly in the form of added sugars (cookies, candy, soda) or refined flour? It’s fine to enjoy your favorite sweet treats and processed foods sometimes, but the bulk of your carbs should come from whole food sources.
Don’t fear fat
The ketogenic diet may seem like the Jekyll to the Hyde-like low-fat craze of the 1990s. The bulk of current research finds that the middle ground between the two extremes is more beneficial for overall health. Make it easy for yourself: Eat at least two servings a week of fatty fish (salmon, sardines, mackerel) and cook with a variety of quality fats (olive oil, canola oil, avocado oil) throughout the week.
Pack in the greens
Leafy vegetables are loaded with nutrients and they’re keto-friendly. There’s kale, spinach, bok choy, Swiss chard, collards, watercress, mizuna, and arugula. Dig in.
Oh, and you might be wondering—how’d things turn out with the bacon beaus? Their experiment worked until life changed. They had a kid. They made a big move. They stopped the diet. “It was too hard to maintain,” she told me. Proof that all the bacon you can handle even grows boring after a while.
Originally posted on Men’s Health