A first, scientists at the University of Warwick in the UK claim to have uncovered how and why specific neurons in the brain control the hunger response. They have revealed a set of pacemaker nerve cells in the brain that appear to underlie the drive to feed which itself feeds on a complex web of signals.
"This research shows that there may indeed be very good reasons why overweight people seem unable to solve their weight problems simply by employing the usual methods, - eating less may be a more difficult and complicated problem than we currently anticipate," report the scientists.
The level of complexity they have found is such that the system could be much more at risk of serious repercussions from a single error in how those signals are processed than anyone had previously thought. Any number of a range of errors could lead to over activity of these pacemaker cells and explain why many people find difficulty in eating less.
Dr David Spanswick and his research team at the University of Warwick's Department of Biological Sciences, looked at a part of the brain called the hypothalamic arcuate nucleus which was known to deal with hunger and satiety signals. A poorly understood area, the team identified very specific neurons that act as feeding 'pacemakers'.
This specific group of neurons - which they have dubbed the 'ARC pacemaker' - produce regular bursts of electrical activity. However these cells integrate and process a wide variety of signals indicating the energy needs of the body signals most often transmitted by the use of chemical messengers such as hormones like ghrelin, released from the gut and leptin from fat cells.
The combination of these signals and their integration by the ARC pacemaker is such, a finely balanced mechanism that one small error or mutation leading to any inappropriate communication in these pathways could produce a significant untoward affect on human eating or feeding patterns, report the reserchers.
Full findings of the Warwick study are published in the May Issue of Nature Neuroscience.
Obesity is one of the main causes of non-communicable diseases. The economic and healthcare costs of NCDs are already high in many developed countries. In the US alone that cost has risen to more than $120 billion annually.
According to the UN-backed Food and Agriculture Organisation(FAO), in developed countries, obesity, diabetes and other NCDs account for a heavy slice of healthcare costs.
The World Health Organisation estimates that in 1995 there were 200 million obese adults worldwide and another 18 million under-five children classified as overweight. In 2000, this number lept up to over 300 million, with over 115 million people suffering from obesity-related problems in the developing countries.