By Dr. Sean M. Wells, DPT, PT, OCS, ATC/L, CSCS, NSCA-CPT, CNPT, Cert-DN

For decades the predominant model that dictated weight gain, loss, or maintenance was the energy balance model (EBM). The EBM is rooted in one of the basic laws of thermodynamics. It goes without saying that food contains energy and it is typically measured in a unit known as calories (kilocalories in the dietary world). As a person consumes food it provides energy to do work such as exercise, activities of daily living (ADL), physical therapy, basic living functions, or even sport. Energy can come from recently consumed food or stored energy (e.g. fat, glycogen, or protein) from previously eaten food. 

Clinicians often explain weight loss to patients as “calories-in versus calories-out” or CICO, which directly relates to the EBM. In brief, CICO helps rehab professionals to explain to clients the balance between the energy coming into their body versus the energy they expend: too much food...