Who Will Control U.S. Agriculture?

Mason Shaw, who oversees what Walmart stocks in its baking aisles, couldn’t figure out why an earthy green powder called moringa was selling so well.

Even after Lisa Curtis, whose line of moringa-based drink mixes has been in Walmart since 2019, told him that the market for so-called superfoods was growing fast, he still didn’t get it.

Then, a year ago, Mr. Shaw sat down to watch “The Tucker Carlson Show.” The guests — Dr. Casey Means, whom President Trump has nominated for surgeon general, and her brother Calley Means, an architect of the “Make America Healthy Again” movement — were talking about the ways big food and drug companies make people sick.