Understanding the drive to eat is a fundamental issue that can throw light on the aetiology of obesity and the inexorable surge of the obesity epidemic. It is proposed here that energy expenditure (EE) is a driver of energy intake (EI). Surprisingly this is a neglected area of thinking in this field. Theoretical writings about obesity often focus on the idea of ‘regulation’ and refer casually to a matching of energy intake and energy expenditure as if this happens automatically and there is nothing to explain. However, biological processes do not happen by accident, and the way in which EE is related to EI requires a justification and an explanation.
It is frequently written that nothing in biology makes sense without the theory of evolution; the processes linking EE and EI are based on an evolutionary perspective. It is proposed that the energy required to maintain vital organs (heart, liver,brain, kidneys, skeletal muscle) represents an irresistible metabolic drive for food (the drive to eat). Much attention in this field has been directed to the inhibition of eating (or lack of it), with formulations lacking a mechanism for driving food behaviour. The evidence that fat free mass and resting metabolic rate constitute major determinants of energy intake has implications for understanding the aetiology and management of obesity.
CORE (COnnecting REpositories)
CORE (COnnecting REpositories)