While fans talk about the amazing weight loss results you may see from cutting so many carbs, there’s one vital truth to keep in mind: “It’s very important to understand that the ketogenic diet doesn’t work the same for everyone,” says the New York City–based dietitian Kristen Mancinelli, RD, author of The Ketogenic Diet: A Scientifically Proven Approach to Fast, Healthy Weight Loss. Your unique body chemistry dictates how you’ll respond to eating this way, but there are some universal truths. Here’s what you can and can’t expect to happen on the diet, including the possible benefits and risks of keto! Your metabolism may increase slightly from keto, says Mancinelli, but the weight loss benefits derive more from the fact that you likely won’t be as hungry. “Are you really going to sit down and eat three avocados and an entire roast chicken? Nope. You won’t be eating the same number of calories because you won’t want to eat that much,” she says. The ketogenic diet may help decrease your appetite. In the short term, before you begin to lose weight, you may also experience what people call the keto flu, a state that lasts about a week as your body adjusts to the diet. That can include extreme fatigue and foggy-headedness. (Not everyone feels this, Mancinelli allows.) Knowing that keto flu is a possibility can help you plan the best time to start the diet. You can also mentally prepare for this transition period — reminding yourself that it’s only temporary can help immensely. For these reasons, “some people won’t be able to stay on it,” says Mancinelli. You should aim to give it at least six weeks. After that, if you feel exhausted or hate eating the food, then the diet is probably not for you. However, if you feel energetic after keto flu symptoms subside within a couple of weeks, which some people report, you may see success with the plan. Long-term research on the keto diet is limited, so there’s no telling for sure what cutting out certain major food groups and cutting carbs will eventually do to your body. Registered dietitians warn that nutrient deficiencies may be possible if you’re on it for too long. A 2019 statement from the National Lipid Association Nutrition and Lifestyle Task Force, which focused broadly on low and very low carbohydrate diets, did not rate this class of diets as superior to other weight loss diets. Their report did cite some potential benefits — for example, effects on managing appetite and cholesterol levels — but it found no clear evidence for claims like cardiovascular benefits, and reiterated that a decision to try these diets should be carefully reviewed with medical experts. (5) Because it’s not a forever diet, there will be life after keto. But even when you go off it, you can expect that your taste preferences will have changed. “You likely won’t want as many carbs, and things will taste extremely sweet,” she says. While everyone’s nutrition requirements differ, generally, you may eat 40 to 45 percent fat and stick to 120 to 150 g of carbs per day to help you keep the weight off, she says. Think about how your lifestyle fits with such a restrictive plan, as well as what you’re willing to give up temporarily (like eating the same foods as your family). Let that be your guide to help you determine if the keto diet is right for you.
