The body monitors fat stores by assessing levels of the hormone which is produced and secreted by fat cells.

Leptin. Leptin is produced by fat cells and released when your body has enough fat in storage. When leptin reaches the brain, it gives your body a feeling of fullness so that you will not want to continue eating. Individuals with leptin resistance, where the leptin hormone signals are not received as they should be, are often overweight because they do not have the same brain signals telling them that their body is full.