Understanding Weight Loss: Back to Basic Algebra
Who knew that the key to understanding weight loss is to go back to 8th grade algebra? I know your probably thinking that weight loss is hard enough and now Im supposed to do math…I’m not having it. BUT- having this knowledge is so powerful and will allow you to understand the basic science behind weight loss. We have all heard that the real key to weight loss is diet and exercise, and guess what, thats right! It boils down to a caloric balance in the body. We must burn more calories then we eat in order to create a negative caloric balance. A negative caloric balance = weight loss. On the other hand, when we eat more calories then we expend, weight gain occurs, due to a positive caloric balance.
So how do we know how many calories we are burning? This is where the math comes in. First we must calculate our basal metabolic rate. Our basal metabolic rate (BMR) is the amount of calories the body burns at rest in a 24 hour period. Even if we stayed in bed all day, the body still uses energy to support vital functions such as breathing, maintaining a heart beat and digestion of food. BMR is the largest component of energy burned per day (about 50-60%).
BMR is based upon your height, weight and age. Here are the equations to calculate your BMR:
Women: BMR = 655 + ( 4.35 x weight in pounds ) + ( 4.7 x height in inches ) – ( 4.7 x age in years )
Men: BMR = 66 + (6.23 x weight in pounds) + ( 12.7 x height in inches ) – ( 6.8 x age in years)
Source: Harris Benedict Equations, recommended by the American College of Sports Medicine
Now if your really not feeling the math, there are plenty of BMR calculators available online. Once BMR is calculated, the next step is to multiply BMR by the appropriate activity factor in order to calculate your total daily energy expenditure (TDEE). This represents the amount of calories your body burns at rest, while exercising and performing activities of daily living (such as working, cooking, cleaning, etc). The activity factor is dependent upon how often and how hard you exercise. There is no surprise that the more frequent and the more intense you exercise, the more energy you expend. Here are the activity factors:
|Sedentary||BMR x 1.2||little to no exercise|
|Lightly Active||BMR x 1.375||light exercise 1-3 days/wk|
|Moderately Active||BMR x 1.55||moderate exercise 3-5 days/wk|
|Very Active||BMR x 1.725||hard exercise 6-7 days/wk|
|Extremely Active||BMR x 1.9||vigorous daily exercise, physical labor job, 2 X day training|
Knowing your TDEE is a great tool to help you reach your fitness goals. Weather you want to lose weight, gain muscle mass or simply maintain where you’re at. For weight loss, aim to consume 85% of your TDEE. Track progress from week to week. Another good rule of thumb for weight loss is to create a 500 calorie deficit per day, either by decreasing caloric intake or increasing caloric burn via exercise. A combination of both is best for adopting a healthy lifestyle. There are 3,500 calories in one pound of fat. So by creating a caloric deficit of 500 cals/day, this leads to 1 pound of weight lost per week. Try various forms of exercise to see what you enjoy and what works best for you. Most of all, use this as a tool to create goals and motivate yourself in your fitness journey!