The following information is basically a summary that is found in Lyle McDonald's Ketogenic Handbook:
First and foremost, for one to lose bodyfat, one must be in a calorie deficit:
-the most simple way to do this is to simply multiply your current bodyweight by 12, this will give you your caloric level that you will need to consume to lose fat ie if you weigh 200lbs, then 200 x 12 = 2400 kCal. This is how much calories you must consume.
The next step is to set your protein intake:
-in the book, Lyle recommends a protein intake of 0,9g/lb bodyweight ie using our 200lb person, he will need to take in around 180g protein per day.
The next step is to limit carb intake:
-carb intake should be less then 30g/day, this equals only to around 120 kCal of carbs coming only from fibrous veg like broccoli, spinach etc.
The next step is to set fat intake:
-this is calculated by subtracting your protein calories and carb calories from your total calorie intake, then divide that number by 9 to get your fat grams
-protein 180 x 4 = 720 kCal
-carbs 30 x 4 = 120 kCal
-fat = (2400 - 720 - 120) ÷ 9 = ±170g
So your macronutrients will be as follows:
Protein = 180g
Fat = 170g
Carbs = <30g
Now that you know your calorie intake and macro nutrient lay out, you must follow the following cycle:
Sunday - Friday Evening: eat the above low carb menu
Friday Evening: start carb load
Saturday: carb load
From Friday evening till Saturday evening the carb load should last between 24-30 hours.
-so if you start carb loading 17:00 Friday, then you should stop carb loading between 17:00 and 23:00 on Saturday.
-during this time you can eat basically what you want, but it is best to keep fat intake lower, protein moderate, and carbs high.