Pastor's right. This isn't as difficult as people make it from a rational standpoint. It's difficult mentally and emotionally. Because it's a lot of what most people don't want to hear.
Overloading your system with too much protein is bad for your kidneys. The bulk of your diet should be complex carbohyrdates. Veggies and whole grains, in particular, will do your body a lot of good. You should cut out all trans fats and strive to get your saturated fats down to zero because they clog your arteries and contribute to more diseases than you can imagine.
What most people eat? High-fat diets filled with simple, sugary carbs. The fats are like food opiates. So people gorge themselves on it and when they get addicted to those foods, it is hard to stop. Sugary, simple-carb comfort foods taste good, so people don't want to get rid of those either.
But its exactly what you need to do. Most people almost intuitively know what is good and bad for them. Whole grains, good. Green veggies (and most other vegetables), good. That processed, bleached, fatty snack food that comes from a plant in the midwest, bad. That big slab of meat with fat dripping off of it, bad. That pint of ice cream with 80 grams of fat in the whole container, bad.
I know the bad stuff tastes good to most people. But get rid of that stuff and you will not just lose weight. You will do something that is actually sustainable and you will create habits that give you the best chance at avoiding bad diseases like diabetes, heart disease, stroke and cancer. No guarantees in life, but you really do reduce your risk factors substantially. I don't know why more people don't think that way as their motivation.
The knowledge is out there. It really is "settled."