A recent survey of registered dietitians named the low-carbohydrate keto diet yet again as the most popular diet in the United States. Powering this diet is fat, and loads of it – all the way up to a hefty 90 per cent of one’s daily calories. Its fans feed social media with before and after photos, crediting the diet for life-altering weight loss or other effects. They swirl butter into their coffee, load up on cheese and eat lonely burgers without their bestie: the bun. Staples like whole grains, legumes, fruit and starchy vegetables are being largely pushed off the plate as devotees strive for ketosis – when the body begins to burn fat instead of glucose as its primary energy source. “America is in a state of carbophobia,” said Whitney Linsenmeyer, a spokeswoman for the Academy of Nutrition and Dietetics. The diet is hailed for dropping pounds, burning more calories, reducing hunger, managing diabetes, treating drug-resistant epilepsy, improving blood pressure and lowering cholesterol, as well as triglycerides, the major storage form of fat in the body. People have reported improved concentration, too. “We see pretty dramatic benefits,” said Dr. William Yancy, director of the Duke Diet and Fitness Center. First, a word: Choosing an eating plan or an approach to eating is very personal. Everyone’s body, tastes and background are unique. The best approach to food intake is one in which you are healthy and nurtured and which matches your social and cultural preference. If you want guidance, it’s recommended you consult with a registered dietitian. What is the ketogenic diet? A “typical” ketogenic diet consists of at least 70 per cent of calories derived from fat, less than 10 per cent from carbs and less than 20 per cent from protein. The ketogenic diet, long used to treat epilepsy in children, calls for 90 per cent of daily calories to come from fat, with the amount of protein or carbs varying as long as it’s 4 grams of fat for every combined 1 gram of carb and protein, according to the American Epilepsy Society. That can mean chowing down on a lot of cheese, butter, eggs, nuts, salmon, bacon, olive oil and non-starchy vegetables such as broccoli, cauliflower, greens and spinach. For the arithmetic-challenged, apps and online programs can do the math for you. (No matter what, the keto diet is vastly different than the USDA dietary recommendations of 45 to 65 per cent of one’s total calories to be carbohydrates, 20 to 35 per cent from fat and 10 to 35 per cent from protein.) The goal of the ketogenic diet is to enter a state of ketosis through fat metabolism. In a ketogenic state, the body uses primarily fat for energy instead of carbohydrates; with low levels of carbohydrate, fats can be converted into ketones to fuel the body. For ketosis, a typical adult must stay below 20 to 50 grams of net carbohydrates – measured as total carbs minus fibre – each day. Crossing that threshold is easy: a thick slice of bread adds 21 carbohydrates, a medium apple 25 and a cup of milk 12. “It’s very restrictive,” said Carla Prado, an associate professor and director of the University of Alberta’s Human Nutrition Research Unit. It’s not just bread and soda that are on the outs but high-sugar fruit and starchy veggies like potatoes, as well as too much protein. Also, dieters have to be on high alert for hidden carbs, often invisible to the eye, yet coating that seemingly keto-friendly fried cheese. Can I lose weight on the keto diet? Yes. Certainly in the short-term, it appears that way. For the first two to six months, there’s evidence that a very low carbohydrate diet can help you lose more weight than the standard high carbohydrate, low-fat diet, according to a new literature review of low-carb diets by the National Lipid Association. “By 12 months, that advantage is essentially gone,” said Carol F. Kirkpatrick, director of Idaho State University’s Wellness Center, and lead author of the new literature review. After that, weight loss seems to equalize between those two popular diet regimens. She said keto is best used to kick start a diet, before transitioning to a carb intake that you can adhere to for the longer term. How long does it take to see results on the keto diet? For some, it’s the promised land of diets. Instead of cringing through carrot sticks, they can fill up guilt-free on chorizo with scrambled eggs. Indeed, some evidence suggests that people feel less hungry while in ketosis, and have fewer cravings. “That’s why it’s become so popular for the general population,” said Dr. Mackenzie C. Cervenka, medical director of Johns Hopkins Hospital’s Adult Epilepsy Diet Center. “Because once you are in ketosis, it’s easy to follow.” Usually, it takes between one to four days to enter the state, doctors say, but it depends on many factors like activity level: a runner, for example, may sprint there faster than a couch potato.