Crowd it out, don't force it out
It's human nature to not only focus on the negative (it's our survival), but to want to have the foods we're trying to cut from our diet.
Tell someone they can't have chocolate or carbs, and all they can think about is chocolate or carbs.
Try this instead
If we stop thinking about the chocolate and pizza, and focus on eating the foods that are going to bring us health and longevity, then we can slowly crowd the other stuff out. Perhaps not completely, but incrementally. And that has to be better than doing nothing!
So what foods am I talking about? I'll give you some examples...
Eat more non-starchy veggies eg 600g or 6-7 cups or 2/3 of a plate full, some raw, some cooked
Have some higher-value fruits like berries, apple, citrus, pears with yoghurt, nuts and seeds
Have plenty of good fats like olive, coconut, avocado and macadamia oils, and butter or ghee to help satiate us and ensure a steady stream of energy
Eat adequate protein (so many of us don't), which helps rebuild our cells and feed our brain
Swap some things out eg eat wild rice instead of white rice, eat sweet potato and pumpkin instead of bread, have 85% dark chocolate instead milk chocolate
Try fermented foods like sauerkraut or kefir or low-sugar kombucha