Metabolism refers to the chemical processes that take place in the body to convert food and drinks into energy. A fast metabolism means that the body burns more calories in a given timeframe, even when at rest, compared to the average for some population or set of people. Here are some key points about fast metabolism:

• A fast metabolism does not necessarily lead to thinness, and people with overweight/obesity often have fast metabolisms.
• Metabolism is partly genetic and largely outside of ones control, but it can be influenced by factors like age, sex, muscle mass, and physical activity.
• People with more lean muscle mass are known to generally have a faster metabolism because they are able to burn more calories while in a state of rest.
• Factors that may contribute to a temporarily faster metabolism include exercise, caffeine, and certain foods.

Its important to note that having a fast metabolism is not necessarily good or bad for health, and weight gain or loss is more related to the balance between calories consumed and calories burned.