MODEL RELEASED. Metabolic chamber. Woman lying in a metabolic chamber designed to study her energy consumption as part of a study into obesity. During the study, her metabolism is monitored to determine how much energy she uses and how much food and oxygen she takes in. This allows the determination of her metabolic rate. People with a low metabolic rate burn their energy more slowly than those with a high rate, meaning that they are more prone to weight gain. Obesity, defined as a body weight in excess of 20% above normal, can cause many life-threatening conditions, including heart disease, diabetes and poor circulation.