>>12816383Find out your body fat percentage. Use that to find out how many lbs of fat you have on your body. Multiple that number by 28. That's the number of calories your body can extract from fat per day. Keep in mind that as you lose fat, this number will decrease.
Next find out your RMR. Subtract the number of calories from above from your RMR. That's how many calories you need to consume to keep your body from eating itself. Add to the number if you're engaging in physical activities.
Since all of these are approximations, you should always round up on the number of calories to consume and maybe add a 10% margin for safety.
For example, if you weigh 180 lbs and have 33% body fat, you have 60 lbs of fat. That means your body can extract 1680 calories from fat over the course of the day. If your RMR is 1800, you will need to eat at least 120 calories to keep your body from breaking down muscle and other body tissue for energy. But the first R in RMR means Resting. You're not resting all day, so calculate the calories for your activities. If that comes up to 1000 calories, you now need to eat at least 1120 calories to keep from burning something other than fat. You'd want to round that up to 1300 to 1500 calories as a safety margin.
