Metabolism and Metabolic Rate
Metabolism and metabolic rate play a role together in the human bodies need for energy and energy balance. Metabolism and metabolic rate define our bodies energy use. Metabolism is the total amount of energy our physiological actions require, while metabolic rate refers to the grand total of of all energy used in the body. Metabolism and metabolic rate are classified differently where metabolic rate is broken down further into the categories of: basil metabolic rate (BMR), resting metabolic rate (RMR), thermal effect of feeding (TEF), exercise activity, and non-exercise activity thermogenesis (NEAT). From my article Carbohydrate Metabolism we learned that words ending in “genesis” mean the creation or new. Let’s take a look at each classification of metabolism and metabolic rate.
Basil Metabolic Rate (BMR)
The correlation between metabolism and metabolic rate when discussing BMR is that this is the bare minimum level of energy used to maintain just the vital functions of the body. Basically, the bare minimum energy (calories) needed to stay alive without any movement or digestive functions. Basil metabolic rate accounts for 70% of the oxygen and calories used each and every day. So when we talk about metabolism and metabolic rate, the BMR uses 70% of all energy needs just for non-activity and movement functions.
Resting Metabolic Rate (RMR)
Metabolism and metabolic rate at rest, or RMR; is considered the level of calories/energy that is needed to sustain the human bodies vital functions at rest. RMR is the total sum of energy used in the: Basil Metabolic Rate, + bodies maintenance activities + physical activity & exercise + NEAT.
Thermic Effect of Feeding (TEF)
During digestion the energy used for metabolism and metabolic rate is referred to as the Thermic Effect of Feeding. It takes into account the energy needed for digestion, absorption, and the conversion of nutrients of digested food. Simply stated, eating increases your metabolic rate. Proteins have the highest thermic effect, while fats have the lowest. This is a very simple understanding of understanding good nutrition and having a low fat diet. Fat just don’t burn energy in the body and tend to stick around. TEF accounts for about 10% of the total energy/calories expended.
Exercise and Activities
Metabolism and metabolic rate are directly influenced by the amount of energy used for “purposeful” exercise and activities that are performed. For people that are sedentary and do not lead a fitness lifestyle, the total daily energy expenditure is roughly around 10% to 15% (most likely even less). For people that lead a fitness lifestyle the daily energy expenditures can be over 30%. Not only does exercise create a higher demand for energy during the activity, it also creates a demand for energy expenditure after the activity is over.
Non-Exercise Activity Thermogenesis (NEAT)
The remaining energy use that needs to be accounted for in metabolism and metabolic rate is the energy used for the “unplanned” energy needs. This includes walking from the car to the office, going grocery shopping, picking up the kids at day care, etc. It is all the energy needed for everything except sleeping, digestion, eating, and purposeful exercise. Even though NEAT contributes the least amount to the bodies daily energy expenditure, it is a great indicator of weight gain or weight loss. This means that NEAT is critical component in how we maintain our body weight and/or develop obesity or lose weight. If you a sedentary you are at a greater risk of becoming overweight.
Total Daily Expenditure of Energy
