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The ketogenic diet — a high-fat and very low-carb eating plan — can be tough to start. After all, it’s likely a radical departure from the way you’re eating now (a typical standard American diet is high in carbohydrates and processed foods). But many people are trying the keto diet, which puts your body in a state of ketosis. That's what happens when your body’s carb-burning switch flips to a fat-burning one, a change that can cause weight loss and has even been credited with controlling diabetes. (1)
Because it lacks carbohydrates, a ketogenic diet is rich in proteins and fats. It typically includes plenty of meats, eggs, processed meats, sausages, cheeses, fish, nuts, butter, oils, seeds, and fibrous vegetables. Because it is so restrictive, it is really hard to follow over the long run. Carbohydrates normally account for at least 50% of the typical American diet. One of the main criticisms of this diet is that many people tend to eat too much protein and poor-quality fats from processed foods, with very few fruits and vegetables. Patients with kidney disease need to be cautious because this diet could worsen their condition. Additionally, some patients may feel a little tired in the beginning, while some may have bad breath, nausea, vomiting, constipation, and sleep problems.
Contrary to what most people think, the keto diet isn’t a high-protein plan; it’s really about cutting carbohydrates and protein. And that protein deficit can be hard on your muscles, research suggests. When you limit carbs from things like fruits, vegetables, and grains, your body starts to steal protein from your muscles and other tissues to transform it into carbohydrate, Notte says. “Protein makes up our organs, our heart, our muscles as well as some hormones, antibodies, and neurotransmitters.”
Con: Results can vary depending on how much fluid you drink. By drinking more water, you dilute the concentration of ketones in the urine and thus a lower level of ketones will be detected on the strips. The strips don’t show a precise ketone level. Finally, and most importantly, as you become increasingly keto-adapted and your body reabsorbs ketones from the urine, urine strips may become unreliable, even if you’re in ketosis.

A small Feb. 20, 2017, study looked at the impact of a six-week ketogenic diet on physical fitness and body composition in 42 healthy adults. The study, published in the journal Nutrition & Metabolism, found a mildly negative impact on physical performance in terms of endurance capacity, peak power and faster exhaustion. Overall, researchers concluded, “Our findings lead us to assume that a [ketogenic diet] does not impact physical fitness in a clinically relevant manner that would impair activities of daily living and aerobic training.” The “significant” weight loss of about 4.4 pounds, on average, did not affect muscle mass or function.
The gist of the eating plan? Taking in so few carbs sends your body into ketosis—a state of burning fat for energy, instead of carbohydrates or sugars, explains Beth Warren, RDN, founder of Beth Warren Nutrition and author of Secrets of a Kosher Girl: A 21-Day Nourishing Plan to Lose Weight and Feel Great (Even If You're Not Jewish). In order to stay in ketosis, you only consume 5% to 10% of your calories from carbohydrates—which for most followers is fewer than 20 grams total per day—and instead eat moderate amounts of protein and high amounts of fat.
This means that to achieve ketosis, you have to limit your carb intake to less than 50 grams per day (most people should reach ketosis within a week of following the diet). To put this in perspective, the low-carb diet you’re most familiar with—the Atkins Diet—recommends about 130 grams of carbs per day. Also for reference, one bagel has about 55 grams of carbs.
Some athletes swear by the ketogenic diet, not just for weight loss but for improved performance in their sport, as well. But Edward Weiss, PhD, associate professor of nutrition and dietetics at Saint Louis University, doesn’t buy it. “I hear cyclists say all the time that they’re faster and better now that they’re on keto, and my first question is, 'Well, how much weight did you lose?'” he says.
I actually clicked on the story just to see if they included anything about it’s use in managing chronic migraine. I have chronic migraine, basically intractable. Nothing has helped. I’ve tried medications, meditations, and everything in between including a bunch of dietary changes. Keto is my next consideration. I’m happy to hear it helped you! Thanks for sharing
I was a Corpsman (not a corpse-man as some recent somewhat fanatical president would say), and I can tell you many stories of Marines and Sailors who maintained restrictive diets (aka picky eaters). Most obvious was lack of sustaining energy (hypoglycemia) at mile 15 (with 80lbs of gear including a 6.5lb rifle and 200 rnds of ammo, etc.) and depletion of essential vitamins, electrolyte imbalance. They were always the first to collapse and have to hear me scold “see I told you so.” An IV of D5W usually does the trick (D is for dextrose, OMG!)
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 nutrient deficiencies and talk about vitamin supplementation, as you won’t be eating whole grains, dairy, or fruit, and will eliminate many veggies. “A diet that eliminates entire food groups is a red flag to me. This isn’t something to take lightly or dive into headfirst with no medical supervision,” she says.
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