Losing weight is a physiological process that consists of loss of body mass and weight loss as the main consequence of the loss of reserve adipose tissue. Weight loss depends essentially on the following factors: • Acceleration of metabolism: for the body to consume more energy than what is introduced through food; • A low-calorie food diet: for the introduction of energy into the body to be less than that spent by the body; • Impact of diet on increasing metabolism: some foods rich in protein are able to accelerate metabolism; • Balance between a low-calorie diet and an increase in metabolism. Generally, when we intend to lose weight, it is essential that our body works essentially based on catabolic processes, which are characterized by the degradation of energy reserve tissues. However, catabolism is not a selective process: when we start a diet aimed at weight loss, in addition to losing reserve tissues, we can also lose other tissues, such as muscles. So, it is necessary to follow a weight loss diet in a careful and judicious manner, under the supervision of a health professional.