The popular low-carb diets (such as Atkins or Paleo) modify a true keto diet. But they come with the same risks if you overdo it on fats and proteins and lay off the carbs. So why do people follow the diets? "They're everywhere, and people hear anecdotally that they work," McManus says. Theories about short-term low-carb diet success include lower appetite because fat burns slower than carbs. "But again, we don't know about the long term," she says. "And eating a restrictive diet, no matter what the plan, is difficult to sustain. Once you resume a normal diet, the weight will likely return."
Before we dive further into weight loss, a note: Weight loss isn't for everybody, and neither is following a specific, restrictive eating plan. If your goal is to lose weight, that's fine, but your health matters more than a number on a scale (and if you have a history of disordered eating, you should discuss any plans to change your diet with a doctor first). In addition, successful long-term weight loss is the product of many factors: Your physical activity, how much sleep you get, stress management, and other factors like medical issues and hormones all play an important role. What you eat is just one part of the weight loss puzzle.
But it's not just the flavor factor. This high-fat, moderate-protein, and very low-carb diet (which is usually broken down as 70 to 75 percent fat, 20 to 25 percent protein, and 5 to 10 percent carbs) can actually leave you feeling physically ill, especially in the beginning. After a week or two on the diet you will enter full ketosis. But until you get there, symptoms like extreme fatigue (the feeling like you can't get out of bed) and the keto "flu" may occur. The keto "flu" is the time where your body is adapting to using ketones as energy, which can leave you feeling nauseated, with headaches, and a foggy head.
That’s why many health experts are concerned about people on the keto diet, especially those who try it without the guidance of a doctor or nutritionist. Doctors say that high-fat diets like this one may raise cholesterol levels, and some studies suggest that they increase the risk of diabetes. Some have even called it a “cardiologist’s nightmare.”

This can be tough for folks who need a "cheat" day, but it can also take a mental toll on the dieter. In a usual diet plan when you go off of it for a day or two, you just get right back in the saddle and start again. With keto it's more than that: You need to start from scratch to get yourself back into ketosis, which can take a few days or weeks. This can really make you feel bad about yourself and take a psychological toll on your well-being and self-worth. (Related: Why You Should Give Up Restrictive Dieting Once and for All)
What's more, it's especially important to make sure your diet is well-planned when you're eating keto-style, because the foods you can choose from are limited. In addition to checking in with a dietitian if you're able, Stefanski recommends that you "talk to your doctor and make sure she or he is aware that you'll be starting a diet that completely changes how your body metabolizes energy." You might also want to check your most recent bloodwork levels for things such as cholesterol, vitamin D, and other indicators of health because these can change while on keto. That's because for some people, a prolonged keto diet can result in certain nutritional deficiencies or even high cholesterol. But most experts will tell you that the ketogenic diet is not a permanent lifestyle change (as could be the case for something like the 80/20 approach to eating or a Mediterranean eating style).
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.

I love this! I am an amateur powerlifter and I have recently started using the keto diet as there is only so much gained by being a fat powerlifter but working out my macros was driving me nuts as I also work as a disability support worker and need to take meals and so on to work with me. Thanks to this I can now have better control of the macros to bring my weight down without doing to much harm to my lifts! Thank you for this!
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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