Honestly don't get all the disagreement here. We all know regaining lost weight is a real risk, but that applies to anyone who loses weight, medication or not.
That said, I think that risk climbs significantly higher if someone's relying purely on nausea and barely eating rather than making real, lasting changes to how they eat. Some people genuinely need to make substantial adjustments. Right now that could look like never heading out for a meal without figuring out ahead of time what to order. Or turning in earlier at night. Seen plenty of posts in this community emphasizing how critical sleep is for weight loss. So many comments about that topic. But somehow not relevant here?
There's also something a little off about framing this as merely cutting back portion sizes of unchanged foods. Once the medication stops, keeping those portions down gets dramatically harder. The injections work by curbing appetite and speeding up fullness. Without actually changing what you eat, you're essentially reverting to whatever pattern led to the extra weight to start with, just minus the medication's help keeping portions