Despite the old adage that metabolism is associated with weight, it’s only a myth. There is not much validity to the ‘belief’ that slender individuals have a high metabolism and overweight people have slow ones.
While certain people may suffer from a thyroid condition which in turn affects the metabolism, weight alone does not determine one’s metabolism.

In actuality, weight loss or gain relies on the amounts of caloric intake and how much energy is expended. When the body has more incoming calories and has less calories being burned, weight gain is inevitable. It makes the most weight sense that reduced caloric consumption triggers weight loss. Metabolism is the motor that uses the body’s fuel or energy.

In terms of medical science’s definition of metabolism, it is the process by which the body extracts energy from food. When the biochemical process transpires, the calories originated from fats, carbohydrates and proteins — are combined with oxygen to discharge the energy the body requires to operate and function.

The amount of calories that the body utilizes to burn calories is referred to as the total energy expenditure. Three fundamental factors are comprised of the total energy expenditure:

-General requirements. Even when the body is sedentary it requires energy for fueling the organs, blood circulation, breathing, regulating hormone levels, the growth and rejuvenation of cells.

-Physical exertion. Exercise coupled with physical activity and other movements account for the utilization and expenditure of calories.

-Food processing. Digestion, absorption and the process of transporting food as well as how it is stored necessitates energy or calorie. These processes account for approximately 10 percent of the calories expended daily. By and large, the body's energy requirements needed to process food remains relatively stable and does not change.

Calories expended to cover these basic functions are your basal metabolic rate. Typically, a person's basal metabolic rate is the largest portion of energy use, representing two-thirds to three-quarters of the calories used each day. Energy needs for these basic functions stay fairly consistent and aren't easily changed.