Currently, no formal scientific definition of overconsumption exists, and the methodologies used in studies that claim to measure overconsumption differ substantially. Therefore, comparison between studies is difficult, and the role of overconsumption in the etiology of obesity is obscured.
Overconsumption is commonly studied in experimental paradigms by comparing food intake between two independent groups of participants. In this way, the lower energy intake is used as benchmark, against which significantly higher energy intake is often classed as ‘overconsumption’. While a complete review of the literature is beyond the scope of this paper, several laboratory studies have used comparisons in this way to assess overconsumption. For example, ad libitum food intake has been compared between participants identified as being high and low in sensitivity to food reward (e.g., ), high and low in dietary restraint (e.g., ), disinhibition (e.g., ) or self control (e.g., ). A related paradigm compares intake between-subjects or within-subjects in a control condition with those subjected to an experimental manipulation, in order to determine its effects upon propensity to overconsume (e.g., [9–11]).
While illustrative, these comparative approaches to assessing overconsumption pose several problems. Although the laboratory environment allows high precision, unfamiliar conditions and possibly foods may provoke atypical eating behaviors , so that observation of a single episode of eating behavior in the laboratory is not a guarantee that it is typical of the individual. More importantly, high levels of individual differences in compensatory behaviors, habitual diet and activity-induced energy expenditure are likely to negate any sustained differences in caloric intake observed in a laboratory. It can be argued that it is meaningless to compare absolute food consumption between subjects, as energy intake and expenditure are so highly variable between individuals. Therefore, the preferred method of assessing overconsumption should be within the context of each individual, with reference to individual energy requirements. However, the issue of for how long consumption should be tracked in order to reveal meaningful changes remains to be addressed.