One of the biggest keys to successful weight management is building and maintaining an active metabolism. For some, this will never be a problem as they have been blessed with a naturally elevated metabolic rate. For many, the challenge of getting and staying as lean as desired is a continuous battle. To make matters worse, in our effort to improve we often do things than can ultimately cause our metabolism to become even less efficient than it originally was. Since there are a number of variables that can affect our metabolic rate, and since our metabolism can be a vital factor in determining our fitness success, it is important that we take some time to understand just exactly what it is and how it works.
What is Metabolism?
Metabolism is the enzyme driven, chemical process of the body that takes place at the cellular level which is necessary to maintain life, and is responsible for such bodily functions as growth, repair, reproduction, and adaptation to environmental change. It is a constant, ongoing process of building up and breaking down that regulates energy consumed and energy expended. It is affected voluntarily such as by the things we do (like exercise) and involuntarily as an adaptation to changes in the environment (like shivering to combat the cold).
The metabolism is made up of two opposing processes:
This is the anabolic or “building up” part of the metabolism that is responsible for building and storing structural proteins which results in the synthesis and/or production of complex molecules like; amino acids, proteins, lipids, cells, etc. This process is responsible for maintenance, growth, tissue repair, and energy storage. The energy that fuels the anabolic process is derived from the energy produced during catabolism.
This is the destructive or “breaking down” part of the metabolism. Catabolic processes are chemical reactions that break down complex molecules into simpler ones to release energy. The energy produced is stored and used for anabolic reactions. In catabolic metabolism, larger molecules like polysaccharides, fats, nucleic acids, and proteins are broken down into smaller units like monosaccharides, fatty acids, nucleotides, and amino acids. The waste products released during catabolism are removed from the body through the skin, kidneys, lungs, and intestines.
Basal Metabolic Rate
BMR is an individual’s minimum caloric requirement necessary to sustain life at rest. It’s the rate at which your body burns energy in the form of calories while you are physically inactive. This is a key factor in weight loss and many people, in an effort to get leaner, implement practices that have a negative effect on their BMR. By slowing down their Basal and/or Resting Metabolic Rate (RMR) the amount of weight/fat they lose in response to exercise and diet becomes so minimized that the amount of exercising and/or dieting they wind up doing creates an ever greater problem.
Here are some factors that influence your Basal Metabolic Rate:
Genetics: Some individuals are born with greater metabolic potential.
Gender: Men have higher BMR’s than women.
Age: Our metabolic rate starts to decline on our 20’s.
Weight: Being heavier due to higher body fat levels lowers the BMR.
Height: Being taller generally means having a faster BMR.
Body Composition: Amount of body fat versus lean mass.
Muscle size: The greater the amount of lean body mass (muscle) the faster the metabolism.
Activity level: Being sedentary slows the metabolic rate.
Response to Exercise: Frequency of exercise, intensity of exercise, duration of exercise, and type of exercise can all have an effect on our metabolic rate.
Amount of calories consumed daily: Restricting calories lowers the BMR
Amount of meals and food consumed over a given time: Due to the thermic effect of food, eating more frequently and/or eating larger amounts of food will increase your metabolism as opposed to eating less often and/or less total food volume.
Illness: Fighting the symptoms and effects of a disease can alter our normal metabolic rate.
Regulation of body temperature to maintain homeostasis: Shivering to combat cold and/or sweating to combat overheating are metabolic adaptations and examples of how the body’s efforts to maintain proper balance can affect the metabolism.
Having a basic knowledge of what the metabolism is and how it works can make it easier to understand how and why your body changes in response to diet and exercise. This can go a long way towards helping you adopt the correct training and nutritional practices.
Photo: Terry Goodlad