Total Energy Expenditure

Weight loss or weight maintenance are given by the balance between the energy that gets into the body in form of food we eat and the energy that we burn. But how do we burn this energy? The Total Daily Energy Expenditure (TEE) is the sum of 3 components: basal metabolic rate (BMR), thermic effect of food (TEF), and physical activity (PA).

Your BMR is the number of calories you burn as your body performs basic life-sustaining functions at rest and it makes up about 60-70% of the calories we use (“burn” or expend). These functions include the beating of our heart, cell production, respiration, the maintenance of body temperature, circulation, and so on.

TEF is the energy expended with food ingestion and digestion, including mastication, absorption, and transportation of nutrients. TEF by some estimates composes as much as 10% of the TEE. There is evidence of interindividual variability of the TEF: some studies indicate that the TEF in obese people is reduced compared to lean individuals, suggesting a lower level of sympathetic nervous system activation and a diminished thermogenic response to food.

The remainder of TEE involves PA, which on average accounts for 15% to 30% of TEE. Physical activity can be further divided into purposeful-voluntary exercise activity thermogenesis (any workout) and non-exercise activity thermogenesis (NEAT). Erroneously, purposeful-voluntary PA has been considered the only major and most modifiable component of daily TEE. Instead, NEAT is not only certainly modifiable but could potentially be an important tool for weight loss or weight management, especially for overweight or sedentary people.