What I like to do is calculate my protein grams first. Multiply your bodyweight by 1.5. This will be your protein intake for the day. And will also be 40% of your calories for the day. From there you can figure out your carb and fat intake which should each be 30%. Low carb diets only work for 3-4 weeks at which time you should switch your carbohydrate and protein values. For example make 40% of your diet carbs and 30% protein...