I originally started with protein diet and casual gym goings. Gym forces you to eat more protein and use up a lot of excess calories. Also, you feel energised and mentally uplifted.

Once you're few months into gym routine, you'll read up more how to hit your macros, how to restructure constituents, how to manage appetite. For now, this all Will overwhelm you and you'll have trouble sticking to any of it. I know I did.

Since you're at the start I suggest simply start noticing healthier options. Do it intentionally for few weeks before even doing anything. When you put more effort into this, you'll discover your own ways how to eat better without the need for fixed "diet".