The ketogenic diet—also known as "keto"—has become the latest big thing in weight-loss plans, touted recently by celebs like Jenna Jameson, Mama June, and Halle Berry. The diet involves cutting way back on carbohydrates, to 50 grams a day or less, to help the body achieve a state of ketosis, in which it has to burn fat (rather than sugar) for energy.
Research to determine the appropriate amount of nutrients for health began in the 1940s because men were being rejected from the military during World War II due to the effects of poor nutrition on their health. The first Food and Nutrition Board was formed to evaluate the nutritional intakes of large populations. Since then, the Food and Nutrition Board has undergone many changes and published comprehensive guidelines on nutrition for both maintenance of good health and disease prevention.
Wondering what fits into a keto diet — and what doesn’t? “It’s so important to know what foods you’ll be eating before you start, and how to incorporate more fats into your diet,” says Kristen Mancinelli, RD, author of The Ketogenic Diet: A Scientifically Proven Approach to Fast, Healthy Weight Loss, who is based in New York City. We asked her for some guidelines.
Lots of apps and websites offer keto diet challenges—basically, a blueprint for the keto diet with a fixed starting and ending point (they typically last for a week to a month, though some may be longer). Speaking of apps, plenty of keto-centric ones are right at your fingertips (a.k.a., your smartphone), like the KetoDiet app, which can help you calculate your macros and track your keto diet effectively.
Focus on diet: It’s true that exercise can give you an immediate surge of energy, but smart eating throughout the day will fuel you with a steadier supply. “With proper nutrition and well-timed meals, you’ll keep your blood sugar balanced. This is important, since blood sugar spikes and drops are a leading cause of energy fluctuations,” says Shawn M. Talbott, Ph.D., a nutritional biochemist in Salt Lake City and the author of The Secret of Vigor ($15, amazon.com). You’ll also help to balance your brain’s neurotransmitters, which are chemical substances (including serotonin, dopamine, and norepinephrine) that keep your mood up and therefore your energy from plummeting.
The keto diet changes the way your body converts food into energy. Eating a lot of fat and very few carbs puts you in ketosis, a metabolic state where your body burns fat instead of carbs for fuel. When your body is unable to get glucose from carbs, your liver converts fatty acids from your diet into ketones, an alternative source of energy. Burning ketones in place of glucose reduces inflammation and spurs weight loss.[1]
Nuts are a great source of heart-healthy fats and also provide protein and essential nutrients. They can give you a source of sustained energy for your workout. Pair them with fresh or dried fruit for a healthy dose of carbohydrates. However, test these options to see how they settle. High-fat foods can slow digestion, and they may make food sit in your stomach too long if your workout is coming up quickly.
Soft drinks, fruit juice, muffins, white rice and white bread are technically low in fat, for example, but the low-fat group was told to avoid those things and eat foods like brown rice, barley, steel-cut oats, lentils, lean meats, low-fat dairy products, quinoa, fresh fruit and legumes. The low-carb group was trained to choose nutritious foods like olive oil, salmon, avocados, hard cheeses, vegetables, nut butters, nuts and seeds, and grass-fed and pasture-raised animal foods.
The Mayo Clinic Diet is the official diet developed by Mayo Clinic, based on research and clinical experience. It focuses on eating healthy foods that taste great and increasing physical activity. It emphasizes that the best way to keep weight off for good is to change your lifestyle and adopt new health habits. This diet can be tailored to your own individual needs and health history — it isn't a one-size-fits-all approach.
Of course, there are so many more reasons to exercise, and physical activity is amazing for your overall health and wellness. It’s just that if you want to lose weight, it may not be the best or only answer. “Honestly, I think people just don’t know where to start,” says Mangieri. “It’s easy to say you’re going to go to the gym for an hour. It’s much harder to think about what you’re eating all day, every day.” She recommends setting goals that are just as specific and achievable for healthy eating, which could be as simple as drinking a big glass of water right when you wake up, getting protein at breakfast, filling half of your plate with colorful vegetables, or going for a walk in the evening, instead of eating ice cream on the couch.
In the mid-1990s, Hollywood producer Jim Abrahams, whose son's severe epilepsy was effectively controlled by the diet, created the Charlie Foundation to promote it. Publicity included an appearance on NBC's Dateline programme and ...First Do No Harm (1997), a made-for-television film starring Meryl Streep. The foundation sponsored a multicentre research study, the results of which—announced in 1996—marked the beginning of renewed scientific interest in the diet.[1]
When you eat foods high in carbohydrates and fat, your body naturally produces glucose. Carbohydrates are the easiest thing for the body to process, and therefore it will use them first – resulting in the excess fats to be stored immediately. In turn, this causes weight gain and health problems that are associated with high fat, high carbohydrate diets (NOT keto).
Make sure that the diet has been studied extensively for safety — and discuss any changes with your physician or registered dietitian before beginning a new diet. (If you don’t have a dietitian, find one in your area at the Academy of Nutrition and Dietetics website.) And do a self-check to ensure the diet fits with your own values and preferences.
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.”

The researchers agree that the diet itself isn’t inherently dangerous. But, cautions Weiss, “If you have any medical condition, if you take any medicine at all – there are lots of things that change how medicines work in our bodies, and nutrition is definitely one of them. If you’re making a real change in your nutrition, you really should talk to your doctor.”

It's hard to avoid that 3 p.m. stomach rumble, when nothing can stand between you and the office vending machine. And while it's fine to eat something to hold you over until dinner (in fact, we encourage it!), some choices will help you keep on your weight-loss track—while others can surely derail you. So at the vending machine, instead of choosing that ever-so-tempting pack of Twizzlers, try a 100-calorie cookie pack or a Nature Valley granola bar. Better yet, bring a snack from home! We're fans of sliced veggies dipped in hummus. Delish!
The ketogenic diet is a high-fat, adequate-protein, low-carbohydrate diet that in medicine is used primarily to treat difficult-to-control (refractory) epilepsy in children. The diet forces the body to burn fats rather than carbohydrates. Normally, the carbohydrates contained in food are converted into glucose, which is then transported around the body and is particularly important in fueling brain function. However, if little carbohydrate remains in the diet, the liver converts fat into fatty acids and ketone bodies. The ketone bodies pass into the brain and replace glucose as an energy source. An elevated level of ketone bodies in the blood, a state known as ketosis, leads to a reduction in the frequency of epileptic seizures.[1] Around half of children and young people with epilepsy who have tried some form of this diet saw the number of seizures drop by at least half, and the effect persists even after discontinuing the diet.[2] Some evidence indicates that adults with epilepsy may benefit from the diet, and that a less strict regimen, such as a modified Atkins diet, is similarly effective.[1] Potential side effects may include constipation, high cholesterol, growth slowing, acidosis, and kidney stones.[3]
Protein is needed to help keep your body growing, maintained, and repaired. For example, the University of Rochester Medical Center reports that red blood cells die after about 120 days. Protein is also essential for building and repairing muscles, helping you enjoy the benefits of your workout. It can be a source of energy when carbohydrates are in short supply, but it’s not a major source of fuel during exercise you’re well-fed.
Atkins products have been tested to ensure that their impact on your blood sugar level is minimal. The majority of Atkins products can be suitable for Phase 1 as long as you don’t sacrifice the intake of foundation vegetables (the requirement is 12 to 15 net carbs daily). If you are in Induction, you have 5 to 8 grams of net carbs to use for dairy, dressings, or Atkins products. You can plan accordingly and customize your diet to your needs!
“Don't like eating meat?” asks Ginger Hultin, RDN, a dietitian in private practice in Seattle and a spokesperson for the Academy of Nutrition and Dietetics. “Then don't be paleo! Travel a lot and rely on eating out? The DASH diet may end in frustration for you.” The bottom line: The diet you choose needs to be safe and effective, while taking into account your lifestyle.
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