That said, there isn’t an agreement that a low-carb diet is superior to any other kind of diet or that it’s healthier long term. A review in the December 2015 issue of Diabetes Therapy that looked at the diet among those with diabetes noted that when it comes to weight loss, a low-carb diet performs no better than other higher-carb diets; and that it doesn’t produce better glycemic control, either. (5) Another report in Diabetes Care also found that over one year, those on a low-carb diet lost weight faster than those on a low-fat one, but after a year, weight loss and A1C levels (an average of blood glucose over about three months) were remarkably similar. (6)
Remember, your water and electrolyte intake needs to go up on a keto diet, and dehydration can exacerbate many keto flu symptoms. There’s no hard and fast recommendation for how much water keto dieters should be drinking, Nico says. But in general, you should be sipping enough so that your urine stays clear or pale yellow. As for electrolytes like sodium? A registered dietitian can help you figure out how much more you should be having and the best places to get it. If you're feeling sick and can't see a nutritionist right away, consider mixing a low-carb electrolyte drink into your water.
Turns out, what’s low carbohydrate for one person isn’t for another. “There’s no medical definition of what low carb is,” says Columbus, Ohio–based Kelly Schmidt, RD. Basically, it’s reducing the number of carbs you eat from your norm. In general, however, a low-carb diet may include 50 to 100 grams (g) of carbohydrates per day, she says. Below that is considered a ketogenic diet, while 100 to 200 g of carbohydrates per day is a moderate-carb diet.
It seems strange that a diet that calls for more fat can raise “good” cholesterol and lower “bad” cholesterol, but ketogenic diets are linked to just that. It may be because the lower levels of insulin that result from these diets can stop your body from making more cholesterol. That means you’re less likely to have high blood pressure, hardened arteries, heart failure, and other heart conditions. It's unclear, however; how long these effects last.
The ketogenic diet is indicated as an adjunctive (additional) treatment in children and young people with drug-resistant epilepsy. It is approved by national clinical guidelines in Scotland, England, and Wales and reimbursed by nearly all US insurance companies. Children with a focal lesion (a single point of brain abnormality causing the epilepsy) who would make suitable candidates for surgery are more likely to become seizure-free with surgery than with the ketogenic diet. About a third of epilepsy centres that offer the ketogenic diet also offer a dietary therapy to adults. Some clinicians consider the two less restrictive dietary variants—the low glycaemic index treatment and the modified Atkins diet—to be more appropriate for adolescents and adults. A liquid form of the ketogenic diet is particularly easy to prepare for, and well tolerated by, infants on formula and children who are tube-fed.
For instance, working with an expert can reduce the risk for dehydration—which can make keto flu symptoms like headache, cramping, nausea, and fatigue worse. Drastically slashing carbs causes the body to excrete a higher volume of water and electrolytes, so you may need to drink more liquids and eat more salt to stay adequately hydrated, Mancinelli explains. How much more is different depending on things like your activity level and age, but a pro can help determine the right amount for you.
Many people have decided to try the ketogenic diet for weight loss. The most recent evidence shows that reducing your carbohydrate intake to a minimum may help you shed a few pounds, at least in the first few weeks to months. However, we don’t really know whether, over the long term, achieving and maintaining ketosis is better for weight loss than other diets. Almost any intervention can cause undesirable consequences, and the ketogenic diet is no different. One of the most well-publicized complications of ketosis is something called “keto flu.”
One downside to a ketogenic diet for weight loss is the difficulty maintaining it. “Studies show that weight loss results from being on a low-carb diet for more than 12 months tend to be the same as being on a normal, healthy diet,” says Mattinson. While you may be eating more satiating fats (like peanut butter, regular butter, or avocado), you’re also way more limited in what’s allowed on the diet, which can make everyday situations, like eating dinner with family or going out with friends, far more difficult. Because people often find it tough to sustain, it’s easy to rely on it as a short-term diet rather than a long-term lifestyle.
The modified Atkins diet reduces seizure frequency by more than 50% in 43% of patients who try it and by more than 90% in 27% of patients. Few adverse effects have been reported, though cholesterol is increased and the diet has not been studied long term. Although based on a smaller data set (126 adults and children from 11 studies over five centres), these results from 2009 compare favorably with the traditional ketogenic diet.