"The harder the experts try to save Americans, the fatter we get. Officials responded by advising Americans to shun fat, which became the official villain of the national dietary guidelines during the 1980s and 1990s. The anti-fat campaign definitely made an impact on the marketing of food, but as we gobbled up all the new low-fat products, we kept getting fatter. Eventually, in 2000, the experts revised the dietary guidelines and conceded that their anti-fat advice may have contributed to diabetes and obesity by unintentionally encouraging Americans to eat more calories.

“When you reduce salt, you reduce blood pressure, but there can also be other adverse and unintended consequences. As more data have accumulated, it’s less and less supportive of the case for salt reduction, but the advocates seem more determined than ever to change policy.”

References:
Findings - When It Comes to Salt, No Rights or Wrongs. Yet. - NYTimes.com.