Unfortunately, there’s no long-term data on ketogenic diets versus other diets. In a 2015 Italian study, those on a ketosis diet lost 26 pounds in three months. About half of the participants stayed on the diet for a year but lost little additional weight in the next nine months. People in a 2014 Spanish study who followed a very-low-calorie ketogenic diet lost an average of 44 pounds in a year—but a third of them dropped out, possibly because it was too hard to maintain.
Achieving optimal ketosis hinges on finding the right balance of macronutrients (or “macros” in keto-speak); these are the elements in your diet that account for the majority of your calories, a.k.a. energy—namely, fat, protein, and carbohydrates. By the way, it’s often “net grams” of carbohydrates that are counted toward your daily intake; “net” deducts the amount of fiber in a food from its carbohydrate total.