Not Everyone Has the Same Risk for Obesity

Not really a new message to readers of my blog – in fact, one wonders that this is even something that needs to be pointed out. It should be evident to most observers that there are indeed a lot of people around with lousy lifestyles, who do not put on weight (even if they want to), while others struggle to get lbs off even with the most religious adherence to diet and exercise.

So yesterday, when I talked about obesity at the Canadian Diabetes Association/Canadian Society of Endocrinology and Metabolism (CDA/CSEM) meeting in Montreal, I not only spoke about the importance of using a clinical staging system for obesity but also emphasized the fact that obesity is indeed a most heterogeneous condition, where failure to recognize the principal contributors to weight gain in an individual is unlikely to result in successful long-term treatment. 

On this note, I was interested to see the publication by Stice and colleagues from in this week’s issue of SCIENCE, which examined the relationship between the propensity for obesity and the sensitivity of the brain (in particular the dorsal striatum) reward response to highly palatable foods.

Thus, using functional MRI studies, Stice and colleagues showed that striatal activation in response to food intake (chocolate milk) is related to current and future increases in body mass and that this relationship is moderated by the presence of variants of the dopamine D2 receptor (DRD2) gene.

Overall the data suggest that some individuals may overeat to compensate for a hypofunctioning dorsal striatum, particularly those with genetic polymorphisms thought to attenuate dopamine signaling in this region.

In other words, while some people may be quite happy with one piece of chocolate, others may need a whole box to experience the same level of satisfaction. Clearly, in a situation where chocolate supply is unlimited, the latter are more likely to overeat or have a much harder time controlling their intake than the former.

This paper was nicely covered by Sharon Kirkey for Canwest Newservices and her story can be read by clicking here.

AMS
Montreal, Quebec