How did CDC allow sugar and beverage industry mislead Americans to fuel the modern obesity epidemic?

Back to early 1960s evidences from many studies already clearly showed sugar is primary driver of obesity. But Harvard scientists, sponsored by sugar and beverage industry, successfully found a scapegoat - diet fat as primary driver behind obesity, therefore dismissed all those evidences and data from sugar epidemiological studies. CDC sided with Harvard scientists, making reduction of dietary fat as the single best intervention of obesity and its related diseases. “Low-Fat” was institutionalized in America. The market was flooded with unhealthy low-fat products.

Entering 1990s when it became undeniable that sugar is primary reason of obesity, they found another scapegoat. This time while admitting sugar as a factor of obesity, they blamed lack of physical exercises as primary reason for obesity. Therefore the negative impact of sugar was diluted. CDC allowed this excuse to continue misleading Americans.

After more than 40 years and when average weight of women is about average weight of men in 1960s, CDC finally officially acknowledged sugar is primary source of obesity in 2011.