speaking as a personal trainer, i'm not sure where to begin with you, as the question is so multi-faceted. some questions need to be addressed: are you currently doing a resistance exercise program? what is your current height/weight? approximately how many calories do you eat per day now? aim for 50% carbs, 25% protein, 25% fat as an easy guideline. rule of thumb: assuming you workout with weights, consume 1 gram of protein per pound of bodyweight..if you weigh 180 lbs, eat 180 grams of protein per day to help build muscle as you 'break it down' through working out. protein can be purchased as a powder, generally a scoop will contain 20 grams of protein..at 4 kilocalories/gram, that's about 80 calories a scoop. your body can only assimilate so much protein at a time..generally anything much over 40-50 grams of protein at a time will 'go to waste'. the best time for protein intake is during the first hour after a workout. be sure to eat plenty of carbs prior to working out for energy..and allow an hour for them to digest. there are a variety of protein bars on the market, many of them come with a lot of sugary carbs (high-glycemic..which are beneficial after a workout)..most don't really contain much fat. at any rate, these forms (powder or bars) are considered 'supplements' to your diet, not the whole ball of wax. you'd have to eat enough of the stuff to make you absolutely sick to get fat in my opinion. you'd puke before you'd get there..
ryan