Metabolism refers to the chemical processes in the body that convert food and drinks into energy. It is a complex process that combines anabolism, which is the storing of energy, supporting new cells, and maintaining body tissues, and catabolism, which is the breaking down of energy to move, heat, and energize the body. A fast metabolism means that the body burns calories at a quicker rate, even while at rest, and requires a high-calorie intake to maintain weight. On the other hand, a slow metabolism means that the body burns calories at a slower rate and requires a higher degree of physical activity to maintain weight.

Factors that affect metabolism include body size, age, gender, genes, and physical activity. While genetics may contribute to differences in metabolic rate, weight gain, and obesity, most studies show that obesity is not solely due to a slow metabolism but rather a result of poor diet and inactivity.

Signs of a fast metabolism include increased calorie burning, difficulty gaining weight, increased breathing, insomnia, and frequent sweating. However, a fast metabolism is not always a good thing, as it can lead to difficulty gaining weight and an increased rate of weight loss.

To have a healthy metabolism, it is recommended to eat a diet of good carbohydrates, a suitable amount of calories, and consistent meals. Strength training or other weight-resistance type exercises can also help build muscles and speed up metabolic rate.