Losing weight and keeping it off is a struggle for many people out there. More often than not, people who have lost weight tend to gain it back rather than keep it off. But why is this?  What in our nature makes it easier to gain the weight back than keep it off? Recent research has sought to find out what happens after weight loss that leads to weight re-gain.  What scientists found was that this weight regain is actually a survival mechanism from our days as hunter gatherers.    So when we lose weight our body see this as a threat to survival and starts of circulated hormones which affect our appetite.  This leads to over-eating and weight regain.