Many things have changed since 1960. Back then the price of gas was 25 cents, house price $12,700, loaf of bread 25 cents, and a pound of hamburger 45 cents. Not so with the CDC definitions of weight. The tables used to determine the current obesity levels are still the same ones used during 1960.
Unrelated, but interesting to note that since 1960, the average weight of a turkey has more than doubled from 15.1 pounds during 1960 to 31.1 pounds during 2017.
According to the US Centers for Disease Control and the US National Center for Health Statistics, as of 2014, close to 71% of US adults age 20 or older are overweight or obese, based on those old tables.
While the world has changed dramatically, the weight definitions for overweight and obese have not changed during the past almost sixty years. The fact that Americans have also increased height and age during that time is not taken into consideration of the weight calculations.
Bottom line, we are comparing current weights to ancient 1960 tables. Also, BMI, as a measure has been debunked by the same CDC which states, "BMI ranges are not exact ranges of healthy and unhealthy weight." According to the BMI table, Dwayne 'The Rock' Johnson and Vin Diesel are both overweight.
Maybe the 1960 definitions and the BMI definitions need to be updated according to modern reality. Since we have achieved two standard deviations above the almost 60 year old tables, it might be time to redefine normal or we will soon be 100% overweight. Then the government agencies will forced to redefine the definition of windmills, as they are wont to do.