How Much Protein, Carbohydrates and Fat Should You Eat? 

Protein
The US Recommended Daily Allowance recommends consuming 0.36 grams of protein per pound of body weight. If you weight 125 lbs. you should eat about 45 grams of protein per day (125 X 0.36 = 45). However, if you lift heavy weights you can increase your protein intake slightly. If you train for endurance stay near 0.36 grams per pound of body weight.

Carbohydrates
It’s recommended that 60% of calories you eat per day come from carbohydrates. To calculate this multiply the number of calories you need by 0.6. If you need 2,000 calories per day, multiply 2000 by 0.6 which equals 1,200 (carbohydrates required per day). In a gram of carbohydrate there are 4 calories. Therefore, 1,200 calories are divided by four which equals 300 grams. This will help you when looking at nutritional labels.

Fat
Your diet should contain no more than 30% total calories from good and bad fat.s If you consume 2,000 calories per day, then no more than 600 calories should come from fat. Fat contains 9 calories per gram, so this comes to 67grams of fat. Good fats (essentially fatty acids or EFAs) are found in certain nuts, flax seed oil, olive oil and omega 3 fatty acids.