No medication in the history of modern weight loss has inspired as much awe as the latest class of obesity drugs. Wegovy and Zepbound are so effective that they are often likened to “magic” and “miracles.” Indeed, the weekly injections, which belong to a broader class known as GLP-1s, can lead to weight loss of 20 percent or more, fueling hype about a future in which many more millions of Americans take them. Major food companies including Nestlé and Conagra are considering tailoring their products to suit GLP-1 users. Underlying all this excitement is a huge assumption: They work for everyone. But for a lot of people, they just don’t. Anita, who lives in Arizona, told me she “took it for granted” that she would lose weight on a GLP-1 drug because “the people around me who were on it were just dropping weight like mad.” Instead, she didn’t shed any pounds. Likewise, Kathryn, from Florida, hasn’t lost any weight since starting the medication in October. “I was really hoping this was something that would …