The original poster messaged separately asking why skipping lunch is even an issue, so answering that here too.
Skipping meals is really just a shortcut, not a strategy. Sure, it lowers your overall calorie count, fine. But on this medication, and honestly with any dietary shift, you have to think in terms of what you can sustain long term.
What you actually want is a high protein, high fiber approach you can stick with. Skipping lunch, especially if it's not already a regular habit, tends to tank blood sugar and spike hunger hard for whatever meal comes next, which undoes the whole point and usually leads to overeating anyway.
Here's what I'd suggest:
1) Run your questions past whoever's prescribing the medication or managing your nutrition.
2) Start logging everything you eat for however long you plan to stay on this medication.
2a) Push protein and fiber up while staying under your target if dropping pounds is the priority.
3) The whole goal is something sustainable once you're off the medication eventually. So ask yourself, this plan where skipping lunch hits your protein, fiber, and calorie numbers, can you actually keep that up every single day, no exceptions, for months straight? If the honest answer is no, or you're already making excuses, then don't build your plan around it.