Oftentimes, people complain that they just cannot lose weight because of their metabolism. Just what is metabolism and what is its role in weight loss? Metabolism is the body’s process of converting food and stored fat into energy. This energy is used to stay warm, move around, and keep vital organs functioning. Metabolism is typically measured in calories.
Resting metabolic rate (RMR) is a component of a person’s total energy expenditure. It represents the calories the body burns to maintain vital body functions (such as heart rate, brain functions, and breathing). It is the number of calories a person would burn if they were awake but at rest all day. RMR makes up approximately 80% of a person’s total metabolism.
What determines a person’s metabolism? Gender, age, weight, body composition (amount of muscle versus fat), level of fitness, physical activity, eating, stimulants, emotional excitement, stress, and gaining and losing weight all impact a person’s metabolism. It is important to know a person’s RMR so the caloric needs can be determined. During weight loss, it is helpful to monitor changes in metabolism for the most effective weight management. RMR can be determined by using estimates or by more accurately being measured.
What happens to metabolism during weight loss? When people lose weight, their metabolism may decrease. This happens because there is a loss of tissue, primarily fat but also some muscle. Also, the metabolism may decrease in response to the lower caloric intake. Exercise can help prevent some muscle loss. The good news is that after weight loss and during weight stabilization, metabolism may increase slightly. It is important to know your RMR so that the caloric needs can be adjusted accordingly in weight maintenance.