Dealt with this exact thing! Started on a GLP1 before it was mainstream or on anyone's radar. Loved eating, always down for food, and since I never actually felt full I'd always finish my whole plate. My friends back then were the same way and our hangouts usually revolved around restaurants.
Started saying stuff like 'oh, I already ate,' 'not really loving the taste of this,' 'already got plans to eat with someone else later, so keeping this light,' 'my stomach's off today,' 'trying to save some cash,' 'if I take these leftovers home I won't need to make lunch tomorrow.' My default became skipping food entirely until we met up, that way I could load up in front of everyone without raising questions. Felt completely absurd but I wasn't comfortable admitting the real reason. Constantly lying got exhausting, so I just stopped making plans with those particular people, and those friendships never really recovered. Honesty really is the better path.