Nobody gets a 7% body by accident, unless he’s a genetic wunderkind or an athlete. To do it, you’ll need to track the foods you eat closely and make sure you’re getting the right amounts of each macronutrient (proteins, carbs, and fats).
To start, multiply your current body weight by 12 to determine the number of calories you should eat. So, if you’re 180 pounds, start eating 2,160 calories daily.
If, however, you’re very overweight—as in, your belly hangs over your waistband—calculate your calories with the body weight you’d like to be. So, if you’re 220 pounds but want to weigh 180, you’d consume 2,160 calories (not 2,640).
Begin consuming one gram of protein per pound of your body weight every day. So a 180-pounder would eat 180 grams (and a 220-pounder who wants to be 180, likewise).
Get 30% of your calories from fat—meaning, Mr. 180 would then eat 648 calories. To make these easier to count, convert them to grams. Since a gram of fat contains nine calories, divide 648 by nine to get 72 grams of fat. The rest of your calories come from carbohydrates.
To calculate these, subtract your fat calories and then your protein calories from the total. Protein and carbohydrates both contain four calories per gram.
So, in the case of the 180 guy, that’s 720 protein calories (180 x 4 = 720). His equation to find his carb allowance would then look like this: 2,160 calories – 648 calories from fat – 720 calories from protein = 792 calories, or 198 grams of carbs.