Early 2013 worldwide obesity had nearly doubled since 1980;
over half a billion adults and 40 million pre-school children were
obese. Shockingly, overweight and obesity nowadays kill more
people worldwide than malnutrition does (WHO, 2013). This Q3 huge
threat to human health has provided an impetus to the research on body weight regulation and energy homeostasis. Energy homeo-stasis requires an accurate match between energy intake, i.e. foodintake and digestion, and energy expenditure, i.e. basal metabolic rate, physical activity and thermogenesis for endotherms. A key hormone coordinating this balance is the almost two decades ago discovered hormone leptin, named after the Greek root leptoz meaning lean