Losing and gaining weight depends largely on the amount of calories you consume and/or burn. Without knowing your calorie needs, it is sometimes difficult to meet your weight goal.
The most effective way to measure your energy expenditure is by using an indirect calorimeter, which measures your oxygen consumption and carbon dioxide expiration. However, that is neither practical nor cheap.
The more convenient method to determine your total energy expenditure is to use equations. Your total energy expenditure requires 3 equations: BMR (Basal Metabolic Rate), PA (Physical Activity) and DT (Diet-induced Thermogenesis). Diet-induced thermogenesis is the thermic effect of food. Keep in mind, the equations will give you a daily estimated energy expenditure.
How to figure out your basal metabolic rate?
BMR is the minimum energy needed to maintain vital functions such as breathing, nervous system, blood pumping, etc.
The Harris-Benedict equation is most commonly used to measure the BMR. This equation is best used on individuals that are sedentary to moderately active. The following equation has been altered for the use of pounds (W) and inches (H).
Weight-124 pounds Height-5’2” 5ft * 12in= 60in + 2in=62in Age 31 years old
BMR: 655.1+539.4+291.4-145.7= 1340 calories
How to figure out your physical activity value?
PA is the calories burned while moving around such as walking, standing, exercise even fidgeting.
Multiply BMR with the appropriate physical activity value below.
|Sedentary work no moving around||1.4-1.5|
|Sedentary work with moving around||1.6-1.7|
|Active standing work||1.8-1.9|
|Strenuous highly active||2-2.4|
1340 (BMR) * 1.6 (PA)= 2144 calories
How to figure out your diet-induced thermogenesis?
DT is the calories burned to process consumed food. This includes digestion, absorption, transport, metabolism and storage of consumed food.
The most common value used to calculate the thermic effect of food is 10%. This is the caloric value of a mixed diet eaten within 24 hours.
1340 (BMR) * 0.1 (DT)= 134 calories
Daily energy expenditure (DEE)= BMR + PA + DT
1340 (BMR) + 804 (PA) + 134 (DT)= 2278 calories
How to lose or gain weight?
One pound of fat equals 3500 calories. To lose one pound a week, you need to create a daily calorie deficient of 500 calories or a total of 3500 calories for the week. To lose two pounds, you need to create a calorie deficient of a 1000 calories a day or a total of 7000 calories a week. The 500 and 1000 calories can be a reduction in calories consumed or amount of calories burned through exercise. Keep in mind, you will want to recalculate your calorie needs after losing approximately 10 pounds.
2278 (DEE) – 500 calories= 1778 calories to lose one pound/week
2278 (DEE) – 1000 calories= 1278 calories to lose two pounds/week
To gain weight, you would do the opposite and consume an extra 500 calories/day (one pound a week).
2278 (DEE) + 500 calories= 2778 calories to gain one pound/week
Gropper, S.S., Smith, J.L. and Groff, J.L. Advanced Nutrition And Human Metabolism. Belmont: Thomson Wadsworth. 2005
Mahan LK, Escott-Stump S. Krause’s Food, Nutrition & Diet Therapy. 11th ed. Philadelphia, PA: Saunders/Elsevier. 2004.
Do you count calories to lose or gain weight?
--Every few months, I will calculate my calories consumed for a few days to keep myself on track. This also helps me stay on track with portion control.