Macronutrients

Carbohydrates
There are two types of carbohydrates, complex and simple. Complex carbohydrates come from starches. Starchy foods are like grains, potatoes, corn, etc. Simple carbohydrates come from sugars. Anything that has sugar or starch has a carbohydrate. A starch is actually a bunch of sugars in a chain, so when your body breaks it down, it'll be a sugar. From one gram of carbohydrate, you get four calories. The purpose of a calorie is to provide energy for the body. It's our main energy source, unlike fat, which is back up energy that we store up. Not only are there simple and complex carbohydrates, but there are also good and bad ones (unrefined and refined). The carbohydrates you eat from candies and sodas are bad because you don't get any kind of nutrients. The good kinds are from the ones that come from nature like fruits and vegetables. They're good for you because they give you nutrition. Any adult's daily diet (getting rid of all the interfering factors) should consist about 60% of carbohydrates, so if you're on a 2000 calorie diet it should be about 1200. For any teenagers (without any interfering factor), it should be roughly 1500- 2200. (http://kidshealth.org/parent/nutrition_fit/nutrition/sugar.html#)

Protein
Proteins are vital for the human body. It should be 10-15% of our daily intake. They are made up of chains of amino acids, which are also very essential for your body. Not only are your muscles, organs, and some of your hormones made up of protein, it also builds and replaces tissue in your body. Aside from these major functions, protein also helps stimulate growth of hair and fingernails. In order to figure out how much protein you need, you need to take your weight, and divide it by two. After having that number, it means you need that much grams of protein everyday. Proteins are known to come from meats, such as beef, veal, and poultry. However, with a vegetarian diet, food such as nuts, cheeses, and whole wheat bread are vital to have enough protein in your diet. Vegetarians must be careful to watch their intake of protein, so they won't take in too much, or too little.

Fats

Fats are definitely an important part of teen's diets. It is necessary to help our bodies to build nerve tissues and get energized. Basically, a fair amount of fat is essential for teens to develop properly. A gram of fat is 9 calories, which is much more than the amount of calories carbohydrates and proteins have. Teens should get about 25-35% of daily caloric intake from fats. Certain vitamins, such as vitamins A, D, E, and K are only able to be absorbed through fats in people's diets.

HEALTHY FATS and examples of foods to eat in moderation:
monounsaturated fats= olive, canola, peanut oil, avocados, nuts, seeds
polyunsaturated fats= vegetable oils, nuts, seeds
omega-3 fatty acids= cold-water fish, flax oil, flaxseeds and walnuts

UNHEALTHY FATS and examples of foods to avoid:
Saturated fats= animal products, palm and coconut oils
Trans fats= commercial baked goods, fried foods, margarine, shortening, partially hydrogenated vegetable oils

Because vegetarians don't eat unhealthy fats, they are at less risk of getting heart disease. Without all the junk fats in their body, they feel better, look better, and seem to be more active.