Metabolism Quiz: What is Metabolism?

Metabolism is a term that in everyday language refers to the breakdown and transformation into energy of the foods we consume. However, metabolism is the sum of all biochemical processes that take place within an organism and includes breathing, fat storage, muscle building, digestion, and circulation of the blood.

Metabolic rate is the rate of energy created per unit of time. This is the rate at which our body burns calories, whether at rest or during exercise. Metabolic rate can be influenced by food consumption, exercise, the temperature of our surroundings, age, sex, gender, emotional state, hormone levels, menstruation, and pregnancy.

Anabolism refers to the buildup of substances while catabolism is the energy-burning process, or breakdown of substances. Anabolism and catabolism are the two components of metabolism.

Hormones produced by the thyroid gland are critical for body function. They regulate metabolic processes and growth. Thyroid hormones affect heart rate, body temperature, blood pressure, conversion of food to energy, and other processes.

Hypothyroidism means there is a lower than normal level of thyroid hormones. Symptoms can be mild and can be similar to those of other diseases and conditions. People with mild decreases in thyroid function may not notice any symptoms. As the condition worsens, symptoms are related to a slowing metabolism.

Those with more muscle tend to have a higher metabolic rate than people with a greater proportion of body fat. A pound of muscle uses around 6 calories a day to maintain itself, while a pound of fat requires only 2 calories/day. This means those with muscle burn calories faster over time.

Men tend to have a higher proportion of muscle and a lower amount of fat than women; as a result, their metabolic rate is typically higher.

Since the body uses more energy to digest and process proteins, a high-protein diet tends to raise the metabolic rate. Many high-protein diets are not healthy, however, since they often contain large amounts of meats and other foods that contain saturated fats.

It's true that metabolic rate slows with age, and for some people, this can be as early as in their 20s. Typically, metabolism begins to slow around age 30 and decreases about 5% every 10 years after age 40. This is at least in part due to the fact that we gain fat and lose muscle mass as we age, requiring fewer calories. Aging can also affect the thyroid gland, further slowing metabolism.

Drastically reducing your caloric intake can backfire, sending your body into starvation mode, in which the metabolic rate slows down. Even skipping meals or taking too long between meals can have this effect. Eating a small healthy snack or meal every 2-3 hours is ideal.

Dehydration can slow down your metabolism, so staying hydrated helps you burn calories. Strength training to build muscle naturally increases the number of calories your body burns both at rest and during exercise. Finally, aerobic exercise can stimulate the metabolism, even in the hours after you stop your workout.