Industrial way of life is obesogenic
Rapid societal changes—for example, in food production, motorised transport and work/home lifestyle patterns—have placed human physiology (which has evolved to cope with an under-supply of food and high energy expenditure) under new stresses, and revealed an underlying genetic tendency to accumulate and conserve energy (i.e. gain weight) in a high proportion of the population. In this sense, obesity can be construed as a normal physiological response to an abnormal environment.
"The unhealthiest foods have also become, systematically, the: tastiest, cheapest, largest portion-ed, most accessible, most available, most marketed, and most fun foods." [6]