“Motivation can only be studied from a biological perspective.” Critically consider this statement.

Taking a biological perspective, there are three basic motivations for eating (Beck, 2000). We need a source of energy, we require the necessary elements for rebuilding cells, manufacturing chemicals, hormones and enzymes that enable the body to function and we need to remove toxins. The primitive goal of feeding behaviour is to maintain the consistency of the nutrient concentration in the body. This basic homeostatic mechanism integrates external energy related stimuli and controls metabolic processes and feeding behaviour. Lashley suggested that behaviours for feeding were controlled by the brain (Lashley, 1938 as cited in Beck, 2000 p.93). It is likely that these controls are in the general region of the hypothalamus (Beck, 2000). Concentrating on obesity, which involves more input than output of energy in eating motivation, this essay will argue that although there are other motivations for eating a biological perspective underpins motivation to overeat.
Obesity is a medical term that describes a state of increased body weight or adipose tissue that is sufficiently great to produce adverse health consequences (Reeve, 2005). It is usually defined as 25% in excess of the norm (Franken, 2002). The tendency to obesity appears to be somewhat genetically determined (O’Rahilly et al.,2003). People who are overweight often come from overweight parents which could be said to be a learned response for over eating (Rozin, 1996). But, adopted children are more likely to resemble their biological parents than their adoptive parents in weight and identical twins, even reared apart are closer in weight than fraternal twins or other siblings (Stunkard, 1991). Two possible explanations are that they inherit a similar metabolic rate or a tendency to eat as a reaction to external