Many of those fighting the bulge resort to crash diets or reduction in calories in a bid to lose weight and to their dismay find that they are not losing much weight. Funnily enough, the fewer calories they consume, the lesser they burn, which does not really make a difference to their weight.
Intriguing as this may be, scientists at Sydney's Garvan Institute of Medical Research and the University of NSW tried to understand the precise brain circuitry behind this phenomenon.
Understanding the processes behind energy balance, scientists found that the neurotransmitter Neuropeptide Y (NPY) which is famous for inducing appetite also had a significant role to play in controlling whether the body burns or conserves energy.
"This study is the first to identify the neurotransmitters and neural pathways that carry signals generated by NPY in the brain to brown fat cells in the body. It is also the first to show a direct connection between Arc NPY, the sympathetic nervous system and the control of energy expenditure. We know that NPY also influences other aspects of the sympathetic nervous system - such as heart rate and gut function - but its control of heat generation through brown fat seems to be the most critical factor in the control of energy expenditure," researchers said.
Researchers found that when people reduce their diet drastically or don't eat at all, the levels of NPY go up significantly. Increased levels of NPY is a hint to the body to kickstart the 'starvation mode' and make an effort to conserve as much energy as possible. As a result, the body begins to store and burn lesser calories by reducing the processes which are quite unnecessary.
It is now amply clear that the brain controls weight loss as well and therefore we need to find a way to trick the body to losing weight by manipulating the NPY circuit. Perhaps, we may need to resort to certain drugs to achieve weight loss.