One study looked at patients with obesity or overweight without diabetes who stopped taking tirzepatide 10 mg or 15 mg after taking it for 36 weeks. Patients who stopped taking tirzepatide experienced a 14% weight regain after 1 year.
However, there are not enough studies to draw scientific conclusions, but all evidence points to what I said.
As does the discussion in places like reddit by people doing it. If they change their habits, they don't gain weight back. If they only change them somewhat, it just happens more slowly.