The classic ketogenic diet is not a balanced diet and only contains tiny portions of fresh fruit and vegetables, fortified cereals and calcium-rich foods. In particular, the B vitamins, calcium and vitamin D must be artificially supplemented. This is achieved by taking two sugar-free supplements designed for the patient's age: a multivitamin with minerals and calcium with vitamin D. A typical day of food for a child on a 4:1 ratio, 1,500 kcal (6,300 kJ) ketogenic diet comprises:
One meta-analysis18 incorporating data from 447 participants found that low-carbohydrate diets not only helped individuals lose weight, but also improved their cholesterol. And another meta-analysis,19 citing 17 clinical trials, found that low-carb diets protected against major cardiovascular risk factors. A third study20 including 119 participants found that low-carbohydrate dieters had lower cholesterol than low-fat dieters after one year.
If you like eating meat and want to lose weight, you might be tempted to try this recent extreme diet fad that proponents have made some pretty outrageous claims about. One: that eating nothing but meat can cure you of autoimmune diseases. The problem is that there’s no good research to support that notion, or any other health claim, for that matter. Indeed, omitting foods known to be good for you — fruits and veggies among them — can lead to a bunch of unwanted side effects, including constipation and potentially dangerous nutrient deficiencies. Still, since you’re cutting out so many food groups, there’s a decent chance you’ll lose weight, experts say. Regardless of any possible benefits you might see, this restrictive approach is definitely one you’ll want to ask your doc about before you even consider diving in.
But people who started following the keto diet noticed weight loss for a few reasons: When you eat carbs, your body retains fluid in order to store carbs for energy (you know, in case it needs it). But when you’re not having much in the carb department, you lose this water weight, says Warren. Also, it's easy to go overboard on carbohydrates—but if you're loading up on fat, it may help curb cravings since it keeps you satisfied.