The following article will answer these questions and provide additional information on how to calculate nutrients.

Calories

There are several formulas which can be used to calculate how many calories you need per day. The Basal Metabolic Rate (BMR) formula is one of the easiest ways to calculate your daily caloric needs.

For adult males, multiply your body weight by 10, then add double the body weight to this value. For example, lets' use a 150 pound male:

1,500 + (2 x 150) = 1,800 cal/day

For adult females, multiply body weight by 10, then add only the body weight (once) to this value. For example, lets' use a 120 pound female:

1,200 + 120 = 1,320 cal/day

Carbohydrates

Experts say that 55 - 60% of normal diet calories come from carbohydrates; complex carbohydrates in particular. This means that if you eat 2,500 calories a day, carbohydrates should supply approximately 1,375 and 1,500 calories.

To calculate grams of carbohydrates, divide the carbohydrate calories by 4.

1,375 / 4 = 343.75 carbs/day

In this example, about 344 to 375 grams of carbohydrates per day would be required.

Protein

When it comes to protein, approximately .7 - .9 grams of protein per pound of body weight should consumed. These numbers vary based on what your goals are and your physical requirements.

For example, strength training athletes would need more than the recommended daily allowance (RDA); about 1.2 - 1.5 grams per pound.

Women naturally have a higher bodyfat percentage than men, so they would use the lower end of the scale.

The following examples would be considered a normal protein intake based on this formula.

150 pounds = 105 - 135 grams of protein per day
160 pounds = 112 - 144 grams of protein per day
170 pounds = 119 - 153 grams of protein per day
180 pounds = 126 - 162 grams of protein per day
190 pounds = 133 - 171 grams of protein per day
200 pounds = 140 - 180 grams of protein per day

Fat

According to studies, no more than 30% of your total daily calories should be from fat. The following chart can help you calculate your fat intake to meet the 30% calories from fat recommendation:

Are these formulas safe for teens?

Yes and no. Most teens will require [up to 20%] less than the normal RDA. Some teens may require more of a particluar nutrient than that which is listed. Ultimately, the proper amount of nutrients required will depend on factors such as age, sex, and goal of the teen.  

It's important to note that although these formulas are accurate for calculating nutrients based on the RDA, they may not be a solution for weight loss or weight gain. In the event that your current weight should need modification, you will more than likely have to alter a certain percentage of a nutrient.