If you're healthy and eating a balanced diet, your body controls how much fat it burns, and you don't normally make or use ketones. But when you cut way back on your calories or carbs, your body will switch to ketosis for energy. It can also happen after exercising for a long time and during pregnancy. For people with uncontrolled diabetes, ketosis is a sign of not using enough insulin.
While following keto, you’re encouraged to eat as much fat as you want, no matter the source (e.g., butter, olive oil, meats, cheeses), until you feel full. Fat can have a strong satiety effect, but following this recommendation may not be comfortable for everyone. According to recent research, fatty foods may increase feelings of nausea and bloating for some people. Beyond potential physical discomfort, it also might not be emotionally comfortable for everyone—after all, keto is still a restrictive diet, which typically is not a good choice for anyone with a disordered relationship to food and eating. And as with any restrictive dietary plan, following a ketogenic diet can present challenges when it comes to social occasions, celebrations, office parties, meals out, etc. It also might be necessary to limit or avoid culturally relevant foods on the diet in order to stay in ketosis. For still other people it will be tough to sustain because carbs aren’t only delicious, they’re omnipresent. Avoiding them day to day means fastidious meal prep and planning, and planning for social events that include food or eating.
Staying in Ketosis long-term: Chronic Ketosis can cause fatigue, muscle soreness, insomnia and nausea. "Unless you have a medical condition that requires you to stay in Ketosis for long-term, you shouldn't stay in that state for a prolonged period without any carb ups," Mavridis suggests. And if you're a beginner, "it’s recommended that you go through the fat-adaptation phase so that your body becomes accustomed to burning both glucose and fat for fuel," says the nutritionist.
The ketogenic diet is indicated as an adjunctive (additional) treatment in children and young people with drug-resistant epilepsy.[25][26] It is approved by national clinical guidelines in Scotland,[26] England and Wales[25] and reimbursed by nearly all US insurance companies.[27] Children with a focal lesion (a single point of brain abnormality causing the epilepsy) who would make suitable candidates for surgery are more likely to become seizure-free with surgery than with the ketogenic diet.[9][28] About a third of epilepsy centres that offer the ketogenic diet also offer a dietary therapy to adults. Some clinicians consider the two less restrictive dietary variants—the low glycaemic index treatment and the modified Atkins diet—to be more appropriate for adolescents and adults.[9] A liquid form of the ketogenic diet is particularly easy to prepare for, and well tolerated by, infants on formula and children who are tube-fed.[5][29]
“I would make broccoli rice or cauliflower rice to at least feel like I was eating some carbs,” she wrote on her blog. “Then I would add protein, so I often ate grilled chicken and fish over broccoli rice, cauliflower rice or spaghetti squash. I mixed in roasted vegetables, fresh salads with homemade dressing, and smoothies made with avocados and bananas.”
Blanket statement: It’s always best to check with your doctor before starting on this regimen. With that said, “the keto diet isn’t recommended for those with liver or kidney disease, or someone with a medical condition, such as a gastrointestinal issue, who can’t metabolize high amounts of dietary fat,” says Sarah Jadin, a Los-Angeles based registered dietitian and founder of Keto Consulting, LLC. If you’ve had your gallbladder removed, the keto diet may be a no-go. Women who are pregnant or breastfeeding and people with certain rare genetic disorders shouldn’t try this diet.

This is a well-known phenomenon with nearly every type of diet: If you relax the rules even a little bit, you suddenly find yourself overeating. Making entire food groups—such as grains, sugar, and other carbohydrates—off-limits helps make them even more attractive, Macri says. This type of reaction goes beyond a psychological reaction—it can also be physical, she says. “Serotonin is one of the feel-good brain chemicals, and when serotonin decreases, such as it does when you’re on a strict low-carb diet, the brain is on high alert for any kind of reward,” she explains. Let some sugar or bread into your diet, and you could be overcome with a desire for more, Macri warns. “This makes it much more likely that you’ll overeat or even binge on those foods.” 


Short for “ketogenic diet,” this eating plan is all about minimizing your carbs and upping your fats to get your body to use fat as a form of energy, says Scott Keatley, R.D., of Keatley Medical Nutrition Therapy. While everyone's body and needs are slightly different, that typically translates to: 60 to 75 percent of your calories from fat, 15 to 30 percent of your calories from protein, and 5 to 10 percent of your calories from carbs.
There are numerous benefits that come with being on keto: from weight loss and increased energy levels to therapeutic medical applications. Most anyone can safely benefit from eating a low-carb, high-fat diet. Below, you’ll find a short list of the benefits you can receive from a ketogenic diet. For a more comprehensive list, you can also read our in-depth article here >
One of the most common side effects of starting the ketogenic diet is the “keto flu.” This term describes the often unpleasant, fatigue-inducing symptoms that occur as the body adjusts from a high-carbohydrate to a low-carbohydrate diet. During the keto flu, the body’s stored glucose begins depleting, and the body starts adapting to producing and utilizing ketones as energy. (2)
The American Heart Association’s recommendations for controlling cholesterol include getting more fiber and limiting your intake of saturated fat, both of which would be extremely difficult on a ketogenic diet. While it’s true that research around saturated fat is still evolving, making room for good sources of fiber and unsaturated fats, which reduce the risk of cardiovascular disease, and allowing for a more balanced intake of nutrients, is ideal. In any case, you should check with your doctor before you start a ketogenic (or any new) diet, especially if you have any health conditions like high blood pressure or high cholesterol.
Make things yourself. While it’s extremely convenient to buy most things pre-made or pre-cooked, it always adds to the price per pound on items. Try prepping veggies ahead of time instead of buying pre-cut ones. Try making your stew meat from a chuck roast. Or, simply try to make your mayo and salad dressings at home. The simplest of things can work to cut down on your overall grocery shopping.

The remaining calories in the keto diet come from protein — about 1 gram (g) per kilogram of body weight, so a 140-pound woman would need about 64 g of protein total. As for carbs: “Every body is different, but most people maintain ketosis with between 20 and 50 g of net carbs per day,” says Mattinson. Total carbohydrates minus fiber equals net carbs, she explains.

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