The 2019 Rock Hard Challenge: Muscle Math

Here’s how to calculate your calories to reach your physique goals.

Nutrition Facts
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Muscle Math

First, decide if your main priority is gaining muscle or losing fat. To simplify the decision-making process, consider this: Your body’s ability to put on muscle rather than fat is determined by its insulin sensitivity, and if you’re currently soft (meaning no visible ab definition whatsoever), any efforts you make to bulk will only make you fatter. For 90% of the people undergoing this program, getting lean will be the ultimate goal, but we’ll show you how to gain and lose accordingly.

To eat for fat loss, set your calories at 12 times your goal body weight. That is, if you want to lose 20 pounds, eat as if you were 20 pounds lighter already. So if you weigh 180 and want to be 160, consume about 1,900 calories daily (160 x 12—you can round the number off). Now determine how those calories break down into grams of protein, carbs, and fat. Set your daily protein intake at one gram per pound of body weight. You need carbs to provide energy for workouts and to recover from training, so, again, one gram per pound is good. As for fat, keep it low to keep calories under control (one gram of fat has more than twice the calories of a gram of protein or carbs), but not so low that you negatively affect hormones like testosterone: Start with 0.4 grams per pound per day. So for our 180-pound man who wants to be 160, his macros are 160 grams of protein, 160 grams of carbs, and 64 grams of fat.

To gain weight (remember, you must already be quite lean to do this), multiply your current weight by 17. So a 160-pound guy who wants to put on muscle size will consume about 2,700 calories daily. From there, the formula is the same as for fat loss—except you’ll want to double the carbs to two grams per pound. Our 160-pounder will then eat 160 grams of protein, 320 grams of carbs, and 64 grams of fat.

Note that these numbers provide just a starting point. If you’re not losing weight after two weeks, cut calories to 10 times your body weight from carbs. For the muscle seeker, you should increase calories to 18g per pound if you’re not gaining, and even as high as 20 if necessary. If the number of carbs you need to eat to put on size seems too daunting, you can add more fat to your meals. For any change you make, give it time to work and make sure you’re hitting your numbers. Always track your macros. For more help, check out the complete guide to our nutrition philosophy at

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