Obesity is a chronic disease and it seems that the heavier you get, the easier it is to put on even more weight.
I can think of many reasons why this may happen: less activity as you get heavier, more “emotional” eating, poorer sleep, to just name a few.
But here is a new idea: fat cells themselves may produce a substance that helps you grow even more fat cells.
This may indeed be the case, according to a study by Kaiping Yang and colleagues from the University of Western Ontario, London, Ontario published last month in the FASEB Journal.
The study was about Neuropeptide Y (NPY), a potent stimulator of hunger. Yang and colleagues not only found that in mouse and rat models of obesity, visceral fat cells can produce NPY, but also that NPY can promote the proliferation of adipocyte precursor cells via the Y1 receptor.
In fact NPY levels in visceral fat tissue were 6-fold higher in an early-life programmed rat model of increased visceral adiposity, but also more than 2-fold higher in visceral fat tissue of obese Zucker rats.
It turns out that at least in rodents, belly fat itself may be a risk factor for even more belly fat.
Would not surprise me if the same was true for humans.
An interesting question is whether or not the NPY made by fat cells can actually enter the brain to stimulate hunger, and thus, cause the animals (and humans?) to eat more - thereby creating a true vicious cycle.
Certainly an intriguing (although somewhat depressing) hypothesis.
AMS
Edmonton, Alberta
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