When patients start on the latest obesity drugs, they find that their food cravings drop away, and then the pounds do too. But when patients go off the drugs, the gears shift into reverse: The food cravings creep back, and then the pounds do too. Within a year of stopping semaglutide—better known by its brand names Wegovy or Ozempic—people regain, on average, two-thirds of the weight they lost. Tirzepatide, also known as Zepbound or Mounjaro, follows a similar pattern. And so the conventional medical wisdom now holds that these obesity drugs are meant to be taken indefinitely, possibly for a lifetime.

To pharmaceutical companies selling the blockbuster drugs—known collectively as GLP-1 drugs, after the natural hormone they mimic—that might be a pretty good proposition. To patients paying more than $1,000 a month out of pocket, not so much. Most Americans simply cannot afford the cost month after month after month.