The basal metabolic rate of the body, scientifically, is the rate at which your body burns calories to release energy. The calories are burned throughout the day as well as night when we are sleeping. It is the fact that body needs energy all the time, even when we are at rest. This is one of the reasons, why skipping meals has the absolute worst effect on the body. It is believed by the experts that activity levels, thyroid function and age are the factors that impact on your metabolism but to some extent. More muscles tend to burn more calories regardless of the fact that how active you are, how old you are, etc.
Muscle tissue works and burn calories 24 hours a day. There are many factors affecting metabolism to more or lesser extent. Muscle Tissue tops the list. Meal Frequency is another important factor. The longer the gap between meals, more the metabolism slows down to save energy. Activity Level also alters metabolism. But it does not make any difference if the ratio of eating to expenditure is not maintained.
Low fat diets result in poor hormone production, which tends to slow down metabolism. Hydration has impacts on metabolism. More than 70% of body functions require water. Scarcity of water causes all systems to slow down and unnecessary stress. Genetics effects metabolism as you may find some people have higher metabolism than others, which cannot be changed.
Hormone production and function such as thyroid affects the metabolism of the body. Stabilizing blood sugar and following some progressive exercise 2-3 times each week is important for balanced metabolism. Stress is the most common factor responsible for slow metabolism because of extra pressure and strain on various systems. It is a common complaint in 30’s that “my metabolism has slowed down“. But it has been found that the metabolism does not slow down considerably due to aging but due to a lack of muscle. We do not lose muscle because of aging but due to a reduction of physical stress or labor.