The easiest macro to calculate in the ketogenic diet is fat. Once you've got your carbs and protein set, simply fill the rest of your daily calorie needs with fat sources. If you find yourself wanting to gain a bit of weight, add approximately 500 calories, or 55 grams. If you want to lose weight, cut down on your fat intake by 200-500 calories, or 22-55 grams.
“Your liver produces ketones all the time, but the rate depends on carbohydrate and protein intake,” says Jeff Volek, Ph.D., R.D., a professor of human sciences at Ohio State University. When the majority of your diet is made up of of carbs and protein, ketogenesis slows. Replacing carbs and protein with fat will put your body into ketosis, thus ramping up ketone production. Essentially, you're burning fat instead of carbs for energy. This process takes about three days to induce.

H. Guldbrand, B. Dizdar, B. Bunjaku, T. Lindström, M. Bachrach-Lindström, M. Fredrikson, C. J. Östgren, F. H. Nystrom, “In Type 2 Diabetes, Randomisation to Advice to Follow a Low-carbohydrate Diet Transiently Improves Glycaemic Control Compared with Advice to Follow a Low-fat Diet Producing a Similar Weight Loss,” Diabetologia (2012) 55: 2118. http://link.springer.com/article/10.1007/s00125-012-2567-4.
In addition to the traditional ketogenic and Atkins diets described above, there are modifications that can be implemented to both of these diets in order to produce greater benefits on an individual basis. One such amendment, called the Modified Atkins Diet (MAD), is structured similarly to the Atkins diet where protein and fat are consumed freely but carbohydrate intake is further restricted, providing an intermediary diet between Atkins and ketogenic diet. This approach is commonly being used with great success among children with epilepsy due to its ability to increase the likelihood of adherence to the diet while still minimizing glucose intake from dietary carbohydrates.[2]
Around this time, Bernarr Macfadden, an American exponent of physical culture, popularised the use of fasting to restore health. His disciple, the osteopathic physician Dr. Hugh William Conklin of Battle Creek, Michigan, began to treat his epilepsy patients by recommending fasting. Conklin conjectured that epileptic seizures were caused when a toxin, secreted from the Peyer's patches in the intestines, was discharged into the bloodstream. He recommended a fast lasting 18 to 25 days to allow this toxin to dissipate. Conklin probably treated hundreds of epilepsy patients with his "water diet" and boasted of a 90% cure rate in children, falling to 50% in adults. Later analysis of Conklin's case records showed 20% of his patients achieved freedom from seizures and 50% had some improvement.[10]
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