Very good question! First, if you have average American size and work out at least 3 times a week, your normal intake of protein should be in the range 90 to 120g per day, ideally in 3 equal portions per meal. Most Americans eat only about half of what they should in protein. As far as carbohydrates are concerned, you should eat proportionally to the amount of aerobic exercise you do. It varies a lot with the metabolic rate of each individual and with his/hers amount of existing body fat. If you have no body fat, you should be eating about 50 to 70g of carbohydrates/day. If you have a lot of body fat, and want to get rid of it, you should cut this number down to about 30 to 40 g per day. NO MORE! Read the labels of all you eat and you will find out what an absurd amount of carbohydrates the average American consumes (all sugars count as carbohydrates as well). Just one Soda will put you above your daily max. if you are overweight (in terms of body fat, not muscles). Weight is a very deceptive measure because it includes all the good stuff that is heavy (muscles, bones, blood) and should be heavy (everyone needs strong muscles and bones, women too). Hope that clarified the issue.

As far as protein is concerned, about .82 grams/lb of lean mass (1.8 gram/kg) has been shown in experiments to be the maximum that the body can effectively use. Any more than this simply becomes empty calories. Carbs are the primary fuel source for the brain and the entire nervous system. In addition, the only fuel source for the red blood cells and the kidneys. The body needs about 130 to 150 grams per day for these functions. The rest will be determined by your activity level and type of activity as well by your goals. However, if you are an athlete, you will need over 200 grams per day otherwise your athletic capabilities will be degraded. Here are some links to info about carbs and protein. http://spartafit.com/nutrition/carbohydr... http://spartafit.com/nutrition/protein.h...

If you have no body fat, you should be eating about 50 to 70g of carbohydrates/day.
If you have a lot of body fat, and want to get rid of it, you should cut this number down to about 30 to 40 g per day. NO MORE!