Specific patterns of behavior put people at risk of developing obesity. Selection of particular types of foods are one of the key factors involved with the development of obesity. Two distinct groups, high-fat and low-fat phenotypes, eat primarily different foods and have different profiles. These differences suggest that HF and LF can be used as a tool to investigate the relationship between biology and the environment (diet) in the control of bodyweight. In this installment of The Practical Scientist we take a look at a paper that further explores the unique characteristics of these two phenotypes.

Key Points from High-fat and Low-fat (behavioral) phenotypes: biology or environment? John E. Blundell and John Cooling

“Although obesity is much more prevalent among HF than LF, some HF are lean with BMI well within the normal range.

It is known that food intake records cannot be regarded as a reliable estimate of food actually consumed (Macdiarmid & Blundell, 1998). For example, using energy intake, BMR is not an acceptable indicator of daily food diary records, and has been shown to be unacceptably low in 39% of women and 29% of men. Moreover, among the obese, under-reporting reached levels of 60% in men and 70% in women. It has now been demonstrated that a defect in one particular gene can lead to obesity through a dramatic increase in food intake characterized as a form of hyperphagia. One characteristic of the food supply (which has been identified as a likely promoter of high energy intake and a positive energy balance) is the prevalence of high-fat foods. However, although the presence of high-fat foods has been identified as a major environmental "risk factor" for weight gain, it is clear that the relationship between a high-fat diet and high BMI is not a biological inevitability (Blundell & Macdiarmid, 1998). Some individuals who habitually consume a high-fat diet do not appear to be gaining weight and are not obese. The present review will throw further light on this issue.

Most researchers adhere to the notion that a person’s metabolic profile plays a major factor in one's proclivity for weight gain and obesity. However, as one becomes obese, one's metabolic characteristics change so that one's state of obesity itself is associated with a different metabolic profile than that which initially instigated the weight gain.