Leptin Resistance:

"Currently, a major topic in the field of obesity research is the link between obesity and the hormone leptin. Some evidence suggests that obese-prone individuals don’t respond to increasing leptin levels in the same way that non-obese-prone individuals do, which is the reason obesity is now being associated with possible “leptin resistance.” Scientists first discovered leptin in 1994, after years of research focused on hormones that affect body weight and calorie intake. While initially researchers believed the discovery could be used to create powerful weight loss supplements