What is Metabolism?

We are all familiar with the metabolism, but not everyone quite understands exactly how the metabolism operates. While obviously, there are the physiological processes, we want to briefly explain the components. The three components that establish our total daily energy expenditure (TDEE; the total of calories expended each day) for the day are resting metabolic rate (RMR), thermic effect of food (TEF), and thermic effect of activity (TEA).

• Resting Metabolic Rate (RMR):
• The energy required for the body to maintain homeostasis and normal daily bodily functions 
• Blood flow
• Breathing
• Heartbeat
• Blinking
• Sleeping
• Bodily movements
• The largest contributor to our TDEE
• Typically makes up roughly 60%-75% of TDEE
• Factors that can influence the percentage of caloric expenditure from RMR:
• Gender
• Age
• Muscle (lean body mass)
• Body composition
• Genes
• Thermic Effect of Food (TEF):
• Energy required for the body to process and store food for energy/nutrients
• The smallest contributor to TDEE
• Makes up about 10% of TDEE
• What can influence TEF?
• Daily caloric intake
• Composition of carbohydrates, fats, and protein from meals
• Diet
• Thermic effect of physical activity (TEA):
• Energy used to use voluntary musculature
• Accounts for about 20% of TDEE
• The percentage of TEA can be increased, with the more physical activity/exercise and individual has that day. Athletes typically have a much higher contribution of TEA than the average person.