That’s one of the things I took away from a fascinating Cato Institute report called, “Why Does the Federal Government Issue Damaging Dietary Guidelines? Lessons from Thomas Jefferson to Today.” Here’s an excerpt:

The American people did as they were advised — not just by the government, but also by the mass media, which reinforced the government’s message.31 A survey performed jointly by the National Heart, Lung, and Blood Institute and the Food and Drug Administration showed that, by 1986, 72 percent of adults “believed that reducing high blood levels of cholesterol would have a large effect on heart disease.”32 Consequently, between 1960 and 2000, their per capita consumption of saturated fatty acids fell from 55 to 46 grams per day, and their per capita consumption of cholesterol fell from 465 to 410 milligrams per day. Meanwhile, their per capita consumption of carbohydrates rose from 380 to 510 grams per day and consumption of fiber rose from 18 to 26 grams per day (Figure 4).33

Figure 4: Obesity and the consumption of different foods in America, 1960-2000

Source: The data come from Shi-Sheng Zhou et al., “B-Vitamin Consumption and the Prevalence of Diabetes and Obesity among US Adults: Population Based Ecological Study,” BMC Public Health 10 (2010): 746, https://doi.org/10.1186/1471-2458-10-746.

Americans also increased their intake of unsaturated vegetable-derived fats chemically modified as trans fats (as in replacing butter with margarine) because it was believed that saturated rather than unsaturated fat was dangerous. So whereas in 1911 per capita consumption of butter was 19 pounds a year to 1 pound of margarine, by 1976 butter consumption had fallen to 4 pounds a year while margarine’s had risen to 12.34 We now know that trans fats lower healthful HDLs, raise the dangerous sLDLs, and are inflammatory. Consequently, in the words of a recent authoritative review, they “contribute significantly to increased risk of coronary heart disease events.”35

Read the whole thing!