Obesity has nearly tripled globally since 1975, a first in the history of our species. It contributes to at least 200 known diseases and complications, including strokes and cancer. Now, there’s a way to solve that problem with a slash. New drugs like Ozempic can cause people to lose 5-24% of their body weight. In Magic Pill: The Extraordinary Benefits and Disturbing Risks of the New Weight Loss Drugs, Johann Hari offers a nuanced explanation, as an overweight person who takes these medicines himself.

Ozempic works by making food intake infeasible beyond small quantities. A hormone called GLP-1 in the gut and brain was found to affect insulin and blood sugar, and affect feelings of satiety. Drug companies invented ‘agonists’ or copies of this hormone that can last longer in the body.

In 2005, it was approved for use by diabetics. When it turned out that these patients were also losing a lot of weight, the Danish company Novo Nordic funded tests on whether it could be used on obese people. As per the official trial results of semaglutide, those who’d been given the drug lost 15% of their body weight, making it the most successful weight-loss drug in history.