8 Triggers That Change Your Metabolism

If you have ever had trouble losing weight, you have probably placed at least some of the blame on a slow metabolism. It is true that your basal metabolic rate (BMR)--the rate at which your body uses calories--can affect your ability to shed pounds. But there are a few external, controllable factors that can slow down that metabolic rate, says Michael West, MD, an endocrinologist with Washington Endocrine Clinic in Washington, DC.

Here are eight triggers that can slow metabolism, some (but not all) of which you can control, to make sure you aren't sabotaging your weight loss efforts.

1. Age: As we get older, our ability to quickly use up calories diminishes, and the metabolism can slow. Older people also tend to have less muscle mass than younger people, which translates to a reduced metabolic rate. While we can't make ourselves younger, Dr. West suggests being diligent about getting enough exercise. The Centers for Disease Control and Prevention suggests that adults 65 and older get two and a half hours of moderate intensity aerobic exercise every week and do strengthening exercises on all the body's major muscle groups at least twice a week.

2. Stress: There are definitely established links between psychological stress and the adrenal system. When nerves are frazzled, the body releases cortisol, a hormone produced by the adrenal system that is linked to weight gain. To make sure stress isn't making weight loss harder, try to calm yourself by reducing controllable stressors and even getting professional help from a counselor if helpful.

3. Poor Sleep Habits: The lack of sleep is significant enough to disrupt metabolic patterns and cause insulin resistance. Insulin resistance is associated with obesity and diabetes. Try to get 7-9 hours of sleep most nights.

4. Lack of exercise: Exercise burns calories and increases metabolic rate. Set aside a dedicated period of time rather than trying to accomplish it during the course of everyday activities. Adults need two and a half hours of moderate-intensity aerobic exercise and twice weekly strength exercise. Although there is no best time to exercise, research says that people that exercise first thing in the morning tend to stay with it longer.

5. Diet: Not eating enough can actually cause your metabolism to slow down in an attempt to conserve calories Eat breakfast to start your "engine" and then small frequent meals when hunger starts. Don't go to bed hungry.

6. Medication: Certain meds for depression and bipolar disorder make weight loss harder. Zypreza is one medication that has been shown to promote weight gain. Often other medications can be substituted.

7. Weather: There is some evidence that exposure to colder temperatures causes an increase in metabolism, as the body attempts to stay warm.

8. Illnesses: Thyroid problems like hypothyroidism, a condition in which the thyroid gland does not produce enough thyroid hormone, can cause body functions to slow down and weight gain to result. In men, low testosterone levels can have the same effect. Medications are available to relieve most of these conditions or even eliminate them. Ask your doctor about screening tests.