Right now we have several factors:.1. A deliberate change in the late 1990s to a BMI "normal weight that the WHO considers “famine victim” to make most people “obese” who were considered “normal” or “thin” under the old body composition system. A 4lb average gain (and inches of height) from the 1990s to the 2000s suddenly made everyone became “obese” and “morbidly obese”..2. SSRIs, SNRIs, NRIs, antiinflammatories, and dozens of other drugs that frequently cause huge weight gains by changing the “set point” or otherwise interfering in metabolism..3. An epidemic of hypothyroidism. Some estimates go as high as 40% of the population..4. Lack of effective treatment for hypothyroidism. Doctors typically only replace part of the T4 a person had, often ignoring T3 completely, thus meaning the person is not effectively treated. T2’s role has been all but ignored..5. Inner city areas where it’s not been safe for kids to play outside for two decades, and thus the exercise they would have gotten as kids in the 1970s and 1980s is just not done.