Many people like to cite their “metabolism” as a reason for why they lose too much or too little weight. But what is metabolism and why is it much more significant than most realize? Let’s look into metabolism and how it works.
Metabolism is all the chemical processes or changes in the body at the cellular level. It begins with food consumption, which is needed for generating energy to keep the body running. The processes that energy controls is everything from breathing and circulating blood to walking and running. The energy found in food must be converted to a usable form for cells to use. There are two types of conversion that occur, however: anabolism (processes that require energy, like pregnancy and repairing DNA) and catabolism (processes that create or release energy, like breaking down muscle and fat to release stored energy during exercise). Catabolism can also be classified as any chemical process involved with the digestion or breakdown of complex molecules into simpler molecules. Food is catabolized by the body to break it down into a usable form.
Metabolism is regulated by hormones, in particular the thyroid hormones, which work closely with the hypothalamus in the brain to maintain both weight and energy balance. There are two common diseases that affect the thyroid hormone and metabolism: hyperthyroidism and hypothyroidism. As the name suggests, hyperthyroidism is when the body releases excess thyroid hormone, which increases the basal metabolic rate (the resting energy expenditure of a person’s body). The excess thyroid hormone encourages weight loss and the rapid breakdown of fats and proteins for energy as the metabolism goes into overdrive. The metabolism in hyperthyroidism goes into overdrive and burns more calories than normal, so the more severe the hyperthyroidism, the more weight lost. In contrast, hypothyroidism has the opposite effect as it lowers overall metabolism when the thyroid does not produce enough hormones. It reduces the number of calories the body burns and leads to weight gain with a slower metabolism, and as it becomes more severe, more weight will likely be gained.
Many factors impact metabolism. The most significant is age, which has four distinct phases: birth to 1 year (very high metabolism, nearly 50% above normal adult metabolism), one to 20 years (metabolism will slowly decline), 20 to 60 (metabolism will remain steady), and 60+ (metabolism will decline). Additionally, sex (as women’s metabolic rate is about 5-10% lower than men’s), diet, exercise, and sleep all also affect metabolism.
Finally, the main question asked by most is if one can increase their metabolism? The answer is complicated. The BMR makes up 70% of metabolism (including all normal cellular functions that occur without conscious participation), 10% of the energy is used to digest food, and physical activity accounts for the remaining 20%. Doing some things like building more muscle and eating enough food can help, but won’t have a significant impact on metabolism, because metabolism naturally regulates itself to meet the body’s needs. Metabolism itself is not rarely the cause of weight gain or loss. In general, if one burns more calories than they gain, they will lose weight.
References
Valdez, Rebecca. “What Is Metabolism?” 8 Feb. 2023, www.verywellhealth.com/metabolism-7098962. Accessed 28 July 2024.
Shomon, Mary. “The Link Between Thyroid Hormones and Weight” 11 Nov. 2022, www.verywellhealth.com/thyroid-hormones-metabolism-and-weight-3233047. Accessed 28 July 2024.
“Metabolism: What It Is, How It Works and Disorders” my.clevelandclinic.org/health/body/21893-metabolism. Accessed 28 July 2024.
“What Is Metabolism?” Definition, Types, Process, 25 Feb. 2018, byjus.com/biology/metabolism/. Accessed 28 July 2024.
Written by Aarushi Rai from MEDILOQUY