Why has there been such an increase in obesity in our country and globally? The answer lies in a simple equation. In order for us to maintain our weight the following must be true:
Energy in - Energy out = 0
"Energy in" has increased dramatically in the recent past. We as a society are eating more and the types of foods we are eating are more concentrated in calories. This has become the norm. You need not go further than the nearest fast food restaurant to know that everything is being "super-sized."
"Energy out" which is controlled by our metabolism and by our activity level has decreased significantly. This change is due primarily as a result of an increase in the sedentary lifestyle. We as a society are much less physically active than our counterparts were a 100 years ago. Our metabolisms have not changed however.
From studies comparing twins separated at birth and different groups of Pima Indians, it is estimated that the amount our genes contribute to whether or not we become obese is between 25% - 70%. Other studies estimate the percentage to be between 50% - 95%. The actual amount is likely to be over 50%. We are no where near completely understanding the complex mosaic of interactions between neuropeptides that controls our metabolism and thus determines if and how obese we become. When that time comes, we might then be able to contemplate safe and effective drug treatment or gene therapy strategies to help us combat obesity. We are no where near that time yet.