The Weight Came Back. The Study Explained Why.

One of the most common questions I hear about the newer weight-loss medications is: “What happens if you stop taking them?” Unfortunately, biology continues to have opinions on the matter.

This June 2026 study by Horn, published in The Lancet, followed adults with obesity who had already lost significant weight on tirzepatide (Zepbound/Mounjaro), a GLP-1/GIP receptor agonist. Researchers found that people who continued the medication maintained substantially more weight loss than those switched to placebo, while those who reduced to a lower dose landed somewhere in between. Participants who stopped treatment were far more likely to regain a significant portion of the weight they had lost.

The findings add to growing evidence that obesity is a chronic condition requiring ongoing treatment, as the body appears to have a strong preference for familiar territory.

Learn More: https://www.thelancet.com/journals/lancet/article/PIIS0140-6736(26)00656-2/abstract