The Components of Metabolism and How Metabolism Works
The Process Of Metabolism
All of the processes that occur in your body require energy. This energy, ultimately, comes from the food you eat. Metabolism can be broken down into two key processes.
- Catabolism is the breakdown of food into the simplest form, in which form it can be used as energy for the body to grow or repair.
- Anabolism is the stage in which the body is built up or repaired. Once our food is transferred into a form that can be used as energy, the body enters an anabolic state. Any energy that is not required for anabolism is stored in the body as fat.
When you eat, your body is put into a catabolic state. Once the food is broken down, your body enters anabolism.
Understanding Metabolic Rate
Your body’s metabolic rate is essentially how efficient your metabolism is. The metabolic rate can be broken down into three components: basal metabolic rate, energy used in physical activity, and the thermic effect of food.
Basal Metabolic Rate
Your BMR is the minimum amount of energy (calories) your body requires at rest to maintain homeostasis. Contrary to popular belief, this accounts for the largest amount of energy expended on a daily basis. There are a number of different factors that affect your BMR, including body size, lean body mass, and body fat. Here’s how some of these factors work with your metabolism:
- Lean muscle burns energy more rapidly than fat cells, so an individual with a higher lean body mass percentage will have a higher BMR than a similarly sized individual with a higher body fat percentage.
- Fasting or crash dieting can significantly decrease your BMR because the decreased amount of energy encourages the body to slow metabolism as a means of preserving the available energy.
- Metabolism also decreases with age because of decreasing muscle tissue, hormonal, and neurological changes.
- Your hormones play a big role in your metabolism and BMR. Imbalances can control how quickly or slowly energy is used. If you think a hormonal imbalance may be a factor in metabolism problems you may be experiencing, see your primary care physician for help restoring the correct balance.
- When you are ill, your BMR will increase because your body has to work harder to perform traditional tasks like anabolism.
- Dietary deficiencies, like reduced intake of iodine, can affect the thyroid, which releases hormones that stimulate metabolism.
- Physical activity can play a role in your metabolism. Let’s talk about this in more detail.
Energy Used In Physical Activity
It is recommended that the average person participates in moderate activity for 150 minutes per week. Typically, energy expenditure during physical activity accounts for about 20 percent of your daily use, compared to the 50-70 percent that your BMR accounts for. It is for this reason that those trying to lose weight consider all of the aspects of metabolism, instead of just diet or just exercise.
The energy expenditure during physical activity is the only component of your metabolic rate that you have any real control over. You burn about 2 kJ/kg/hr when sitting at the computer or watching TV, whereas you burn about 30 kJ/kg/hr when you are running. You can manipulate the energy expenditure used during physical activity by increasing or decreasing time spent doing more strenuous exercises. When you do this, your body composition will change, having an indirect effect on your BMR. There are so many factors that play into your metabolism, it is important to understand all of them when attempting to decrease body fat or increase lean body mass.
The third and final component of your metabolic rate is the thermic effect of the food you eat. Let’s talk about that.
Thermic Effect Of Food
There is a minute amount of energy used in the process of eating, digesting, and metabolizing food. In the average person, this accounts for about 5 or 10 percent of your total energy expenditure. You may have heard that foods like celery have a negative caloric effect because it takes more energy to digest celery than the celery is actually worth. This is a bit of an oversimplification of how your metabolism works, but the foundation is there. Your BMR will rise after you eat because there is a certain amount of energy required to digest the food. The amount your BMR rises depends on the size and type of food eaten, but the change in your metabolism is rooted more heavily in the type of macronutrients you are consuming than how hard or easy food is to eat. On average:
- Fats will raise your BMR by 0-5%
- Carbohydrates will raise your BMR by 5-10%
- Proteins will raise your BMR bt 20-30%
Your energy expenditure during physical activity and the thermic effect of food, among other factors, can have an impact on your basal metabolic rate, which is more or less the driving factor of your metabolism. Understanding how these factors influence the way your body breaks down and uses energy in catabolism and anabolism is essential to achieving your physical wellness goals.
Your Metabolism And Weight Loss Goals
A functioning metabolism is essential to achieving your physical goals, whether it be fat loss of lean muscle gain. If you are interested in learning more about how your metabolism is functioning and how changes you make to your diet, exercise and lifestyle can impact your metabolism and, in turn, your physical goals, contact our expert at Whole Intent today.