Reasons for Slow Metabolism

As you age, your metabolism slows.
i Jupiterimages/Comstock/Getty Images

From keeping your muscles moving to transferring red blood cells to your lungs, your body uses a significant amount of energy on a daily basis. The energy needed for these and other chemical reactions is known as your metabolism. Differences in metabolism explain why you can eat the same hamburger and French fries as your best friend but you are the one who puts on weight while she does not. However, if your metabolism seems to be slower than normal, there may be some medical and lifestyle reasons for this. Always speak to your physician if you are concerned you may be experiencing an underlying medical condition.

Age and Gender

    You cannot control some aspects of your metabolism's speed. For example, men tend to have higher metabolisms because they have a higher percentage of muscle and a lower percentage of fat than women. Also, age-related loss of muscle mass can slow your metabolism. While the changes may be gradual as you age, they can add up over time.


    Your thyroid is responsible for releasing hormones that regulate your metabolism. If your thyroid is not as active as it should be, you can experience a condition known as hypothyroidism. Because your body is not making enough hormones to keep your metabolism running at the right pace, you will not burn calories as quickly. This can result in symptoms such as sudden weight gain, increased sensitivity to cold, depression and heavier-than-normal menstrual periods. If you suspect you may be experiencing this condition, talk to your doctor who can perform a blood test to measure the amount of thyroid hormone in your blood. This condition may be corrected through lifestyle changes and thyroid hormone supplements.

Physical Inactivity

    One method you can use to increase your metabolism is by engaging in regular physical activity. Those who are more physically fit tend to have a faster metabolism than those who do not, according to KidsHealth. Building greater muscle mass also helps boost your metabolism. If you are not physically active, your metabolism is likely slower than your more active counterparts.

Unhealthy Habits

    While you may blame your inability to lose weight on a “slow metabolism,” you may want to first ensure you are practicing healthy habits before blaming your thyroid. According to Donald Hensrud, MD, a physician writing on, unhealthy habits such as skipping meals can slow down your metabolism. Other bad habits include overeating and not getting enough sleep. If you have healthy lifestyle habits and continue to gain weight, however, you should see your physician to determine a possible underlying medical condition.

the nest