The 1994 discovery of the hormone Leptin has led to exponential incremental scientific discoveries and now its role (in obesity in particular) is becoming more widely known.
“Jeffrey M. Friedman, whose  discovery of the hormone leptin has transformed our understanding of obesity, will be a 2020 recipient of the Breakthrough Prize in Life Sciences. He is being honored for his discovery of a new endocrine system through which adipose tissue signals the brain to regulate food intake. Friedman is the Marilyn M. Simpson Professor and head of the Laboratory of Molecular Genetics at Rockefeller, as well as a Howard Hughes Medical Institute Investigator.
“The relatively new Breakthrough Prize, with its accompanying $3 million award, is the most generous prize in the sciences, and recognizes achievements in the life sciences, fundamental physics, and mathematics. The prize was established eight years ago by several Silicon Valley tech entrepreneurs, including the founders of Google, Facebook, and 23andMe.
“Friedman’s 1994 discovery of leptin, and of its receptor in the brain encoded by the obese gene, shed new light on the pathogenesis of obesity. He and his colleagues have since shown that leptin acts on sets of neurons in brain centers that regulate food intake and energy expenditure, and has powerful effects on reproduction, metabolism, other endocrine systems, and immune function.”
Jeffrey M. Friedman’s latest Nature article:
“Leptin and the endocrine control of energy balance.” – Jeffrey M. Friedman, Nature, August 29, 2019.
(pdf download available.)
I’ll add that leptin research is not limited to leptin deficiency.
There is work being done on how leptin (satiety hormone) and ghrelin (hunger hormone) levels can be altered by diet in beneficial and harmful ways.
One point of discovery is that crash dieting (most dieting, thanks partly to our desire for quick fixes and sound bites) leads to hormone imbalances and binge/regain yo-yoing.
“Getting healthy” should not be a punishment!