When you consume fewer calories than your body needs, your body turns to fat for energy. Your fat cells (triglycerides) provide the fuel for this energy.
Through a series of complex metabolic processes, triglycerides are broken down into two different components — glycerol and fatty acids — which are absorbed into your liver, kidney and muscle. Here, these components are further broken down by chemical processes that ultimately produce energy for your body.
The heat generated through these activities is used to help maintain your body temperature. The waste products that result are water and carbon dioxide. You excrete water primarily in urine and sweat and carbon dioxide in air exhaled from your lungs.
