your skinny and want muscle?

1. Maximize muscle building. The more protein your body stores—in a process called protein synthesis—the larger your muscles grow. But your body is constantly draining its protein reserves for other uses—making hormones, for instance. The result is less protein available for muscle building. To counteract that, you need to build and store new proteins faster than your body breaks down old ones.

2. Eat meat. Shoot for about 1 gram of protein per pound of body weight, which is roughly the maximum amount your body can use in a day. (For example, a 160-pound man should consume 160 grams of protein a day—the amount he'd get from an 8-ounce chicken breast, 1 cup of cottage cheese, a roast-beef sandwich, two eggs, a glass of milk, and 2 ounces of peanuts.) Split the rest of your daily calories equally between carbohydrates and fats.

3. Eat more. In addition to adequate protein, you need more calories. Use the following formula to calculate the number you need to take in daily to gain 1 pound a week. (Give yourself 2 weeks for results to show up on the bathroom scale. If you haven't gained by then, increase your calories by 500 a day.)

A. Your weight in pounds: _____
B. Multiply A by 12 to get your basic calorie needs: _____
C. Multiply B by 1.6 to estimate your resting metabolic rate (calorie burn without factoring in exercise): _____
D. Strength training: Multiply the number of minutes you lift weights per week by 5: _____
E. Aerobic training: Multiply the number of minutes per week that you run, cycle, and play sports by 8: _____
F. Add D and E, and divide by 7: _____
G. Add C and F to get your daily calorie needs: _____
H. Add 500 to G: _____. This is your estimated daily calorie needs to gain 1 pound a week.

4. Work your biggest muscles. If you're a beginner, just about any workout will be intense enough to increase protein synthesis. But if you've been lifting for a while, you'll build the most muscle quickest if you focus on the large muscle groups, like the chest, back, and legs. Add squats, deadlifts, pullups, bent-over rows, bench presses, dips, and military presses to your workout. Do two or three sets of eight to 12 repetitions, with about 60 seconds' rest between sets.