Strength for Her

The key to weight maintenance is making sure you take in the same amount of calories that you burn. If your goal is weight loss, you must burn more calories than you consume. Conversely, if you need to gain weight, you’ll need to eat more calories than you burn off.

It takes an excess of 3,500 calories to add a pound of weight. Although that sounds like a lot, it’s only an extra 500 calories every day for a week! It’s not that hard to eat those extra calories - it could be one indulgent dessert every night. Of course, it’s ok to indulge from time to time. If you’d like to eat a sinful dessert, you can cut back on calories elsewhere in the day so you’re not going over your recommended allowance. It’s all about balance. But before you can understand how to maintain a caloric balance, you first need to know how many calories your body needs each day.

The body burns calories in the following ways:

• Basal Metabolic Rate (BMR) - the amount of calories burned by our involuntary body processes while at rest. This is the energy required to operate our organs and body functions and keep us alive. This accounts for about 70% of our body’s energy expenditure.
• Thermogenic Rate – the amount of calories required for the digestions of food. This accounts for about 10% of our body’s energy expenditure.
• Physical Activity – the amount calories burned by doing any sort of voluntary physical movements. This can be normal daily movements like walking or moving your arms, as well as more intense exercise. The longer and more intense the activity, the more calories burned.  This accounts for about 20% of our body’s energy expenditure.

Many people are surprised to learn that the large majority of our calories are used to just keep the body running and are burned by doing absolutely nothing!

How Many Calories Do I Need?

When looking at nutritional information, it will list the actual number of calories, as well as a percentage of the recommended daily allowance. This daily allowance is usually based on a 2000 calorie per day diet. However, people’s caloric needs vary widely. You may find that you need more or less than this general recommendation.

Smaller bodies require less energy, or calories, to operate. Think about picking up a box. You have to expend a lot more effort and energy to lift a heavy box filled with books versus a light one filled with pillows. It requires more work or energy to move a heavier load. In the same sense, a lighter body needs less energy to move. So a 100 pound person will not burn as many calories as a 200 pound person during an identical workout. The smaller person simply doesn’t need as much energy. It’s basic physics. Because of this, a lighter person has a lower daily calorie requirement.

Calorie needs aren’t based on weight alone, but on many factors:

•  Body composition – a person with a lot of muscle and lean mass will burn more calories than a person of similar weight composed of fat. This is because muscle tissue requires more energy and burns more calories than fat.
• Gender – Men typically burn more calories than women, usually because they have more muscle mass.
• Lifestyle – a person with a very active lifestyle will burn a lot more calories throughout the day and therefore have higher daily caloric requirements
• Metabolism – some people simply have higher metabolisms than others, and burn through calories faster. These people therefore require more calories than those with slower metabolisms.
• Age – the metabolism slows down as we age, so an older person won’t require as many calories as a younger person.

Confused yet? You’re not alone. It’s almost impossible to determine an exact number for your caloric requirement. There are some calculations you can use to help estimate this number, but there really is no way to make an exact accurate determination. For now, just worry about getting a general estimation.

To calculate the body’s total calorie needs, first we need to estimate our BMR. From that number, we’ll calculate our Active Metabolic Rate (AMR), which is the amount of calories needed to power both our body processes (BMR) and our physical activity.

How to Calculate BMR:

Most calorie calculators use the Harris-Benedict equation. However, this method has been criticized recently for overestimation calorie needs. A more accurate estimation can be found through the Mifflin-St Jeor equation, as follows:

Female: 4.54 x weight (lbs) + 15.875 x height (inches) -5 x age (years) - 161

Male:     4.54 x weight (lbs) + 15.875 x height (inches) -5 x age (years) + 5

If you’re not good at math, click here to use our handy BMR calculator.

After calculating your BMR, you’re then ready to calculate your total daily requirements, or AMR.

How to Calculate AMR:

• If you are sedentary (little or no exercise): Multiply BMR x 1.2
• If you are lightly active (light exercise/work 1-3 days per week): Multiply BMR x 1.375
• If you are moderately active (moderate exercise/work 3-5 days per week): Multiply BMR x 1.55
• If you are very active (hard exercise/work 6-7 days a week): Multiply BMR x 1.725
• If you are extra active (very hard exercise/work 6-7 days a week): Multiply BMR x 1.9

Your AMR will give you an estimation of how many calories you need each day. Remember, these calculations are just estimations. It’s impossible to predict calorie needs with certainty because people vary so widely. Still, it’s a good starting point for your weight maintenance efforts.

To figure out your AMR, see our handy Calorie Calculator. We’ll discuss how use this number and keep track of your daily calories in an upcoming article, How to Count Calories.