For decades, rates of obesity in the US have climbed – but that trend may be changing. The number of adults with obesity dipped ever so slightly in 2023, suggesting the country has reached a turning point in this public health crisis. The rise of weight-loss drugs, such as Ozempic and Wegovy, has prompted some to suggest these may be driving the shift. But it isn’t that simple.

Obesity rates began to rise in the US during the 1970s. Between 1976 and 1980, 15 per cent of adults in…