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Fat in, fat off?

Dear Lucy: I’ve been hearing a lot about the “keto diet” recently. One of my Facebook friends swears by it. He says the diet altered his metabolism so he’s constantly burning fat. Is this legit? Is it safe? Does it work? —Ketone Kop

Dear K-Squared: Like you, Lucy’s been hearing more and more about the “ketogenic diet” lately, so she thanks you for asking this question. Fortunately, Lucy knew just where to turn for the answers we both are seeking: MIT Medical’s fearless and intrepid nutritionist and registered dietician, Anna Jasonides.
According to Jasonides, the ketogenic diet is somewhat similar to other low-carb diets, just more intense and restrictive. On a ketogenic diet, one eats only about 20 grams of carbohydrates a day, she explains, equivalent to a single slice of bread or two cups cooked vegetables. “The rest is protein and a lot of fat—oils, butter, cheese, bacon, meats and, other animal proteins. Hardly anything else is allowed, including fruits, milk, yogurt, beans, or grains.”
The goal, she continues, is to induce “ketosis,” which is when the body begins burning fat, rather than glucose, to survive. “When someone is in ketosis,” she says, “the liver produces more ketones than normal.” Most people on ketogenic diets will be able to compensate, but for people with diabetes, excess ketones can be deadly. 
“People on the diet often experience nausea, constipation, dehydration, and weakness for the first few weeks,” Jasonides notes. “Some long-term studies have shown deficiencies in micronutrients, and some experts worry about high cholesterol levels, kidney stones, and osteoporosis.” 
But, in answer to your question, “it’s legit,” Jasonides says. “It does produce a faster initial weight loss when compared to many other diets. But this advantage disappears over time.” 
The main challenge, she says, is compliance. “In my experience, the restrictive ketogenic diet is hard to follow, even for a short time. Adopting a healthier lower-carbohydrate diet can allow you to lose weight and keep it off without going into ketosis. Replacing added sugar and refined-carbohydrate foods with unprocessed carbohydrates and whole foods is healthier, more sustainable, and delicious.”
If you want help reviewing your current diet and finding a weight-loss plan that will work for you, ask your primary care provider at MIT Medical for a referral to our Nutrition Service. Jasonides is willing and able to help you come up with strategies to improve your diet and reach your health and weight-loss goals. —Lucy

Back to Ask Lucy Information contained in Ask Lucy is intended solely for general educational purposes and is not intended as professional medical advice related to individual situations. Always obtain the advice of a qualified healthcare professional if you need medical diagnosis, advice, or treatment. Never disregard medical advice you have received, nor delay getting such advice, because of something you read in this column.