Energy Expenditure

How do we use the energy (calories) we consume?

4 components of your total daily energy expenditure (TDEE):

1. Resting Metabolic Rate (RMR) or Basal Metabolic Rate (BMR)

2. The Thermic Effect of Feeding (TEF)

3. The Thermic Effect of Activity (TEA)

4. Non-Exercising Activity Thermogenesis (NEAT)

The majority of energy consumed is used for fuel to support and maintain normal body functions, like temperature regulation. The rest is used to digest food and support movement for exercise and leisure activities.

RMR

The total number of calories burned when the body is completely at rest (aka basal metabolic rate). Breathing, circulating blood, organ functions and basic neurological functions. High RMR may be due in part to a high level of lean body mass (muscle), high production of thyroid hormones, being a super hero, etc. Low thyroid production, high body fat percentage and low level of lean body mass = low RMR.

RMR is proportional to lean body mass and decreases approximately 0.01 kcal\min for each 1% increase in body fatness. RMR also declines with age: 2% and 3% per decade for men and women, respectively, due to a loss in lean body mass.

Prolonged dieting and repeated bouts of weight cycling (weight loss followed by weight gain) may lead to short-term and possibly long-term regulation of RMR, although the research is inconclusive at this point. Don't worry the majority of you reading this won't fall in to this category.

TEF

Represents the increase in energy expenditure after consuming a meal. 10% of daily energy expenditure is consuming, digesting and utilizing food. Simple carbs and fats have lower them effects of energy compared to protein. Eating higher protein meals has a higher thermic response vs high carb meals.

TEA

Thermic effect of activity accounts for the most variability of daily energy expenditure. 15-30%. Physical work, gym workout and planned and structured exercise.

NEAT

Non-exercise activity thermogenesis. Energy expended for everything we do that is not sleeping, eating or exercising. Walking to work, typing, walking to and from meetings, fidgeting. The more active a lifestyle, the higher the NEAT.

According to the U.S. Department of Agriculture, less than 5% of adults participate in 30 minutes of physical activity each day. According to the U.S. Department of Health and Human Services, only one in three adults receives the recommended amount of physical activity each week. Only 35 to 44% of adults 75 years or older are physically active, and 28 to 34% of adults ages 65 to 74 are physically active (Centers for Disease Control and Prevention). More than 80% of adults do not meet the guidelines for both aerobic and muscle-strengthening activities, and more than 80% of adolescents do not do enough aerobic physical activity to meet the guidelines for youths (U.S. Department of Health and Human Services).

Sources: NASM 2019