The big change for me is on days when I am hunting I really don't eat big meals if anything I have snacks through out the day to keep me full. I do however try to lay off bad food the night before I hunt so I don't have to use my emergency role of TP I keep in my pack.
I don't change anything about my diet. But I ALWAYS pay attention to the wind. If the wind direction isn't good, I'm not comfortable hunting the stand I'm in. My father-in-law has worked all day on the farm, gone straight to his stand before dark without taking a shower and getting scent free, and killed nice bucks. This is because he pays attention to the wind direction. However, I always try to get as scent free as possible. Good luck to you this season! I hope you get hooked!
I would think the worse thing you could switch to would be a more fibre diet...I always find that increases the intestinal activity.
I've read scientific studies that prove that red meat consumption changes your scent. Something to do with if you eat like a predator, you smell like a predator. After doing a little more research, I actually found that the native americans would limit their red meat consumption before big hunts. I personally feel like I stink no matter what I do. Even though I take every precaution to "eliminate" my scent, I just sweat too much walking into my stand to not give off a lot of human scent.