On a Diet

Since the 1950s, significant numbers of Americans have dieted to lose weight or improve health. As the nation’s food supply expanded and included more processed foods, so did concerns about the relationship between food, body image, and health.

Food advice, based—often, but not always—on new scientific research, has come from diverse government and private sources. Over time, guidelines have also been contradictory, leaving consumers confused about what to eat and what to avoid. Various fad diets found fleeting favor in the late 1900s, but by the 2010s an underlying message kept emerging: if you can, eat more vegetables and fruits, fewer processed foods, and as Julia Child famously said, “eat everything in moderation.”