It seems the best food isn't cooked much or is cooked in a plain manner. Oatmeal is just oats plus water. Likewise, Shredded Wheat is only whole wheat with no added sugar, etc. Add a few blueberries, strawberries or banana to that and it makes a very nutritious breakfast. Lactose-free fat-free milk adds essentially no fat. You don't need to add salt either. Salads and fruit are best just as they are without adding dressing or cheese or croutons.
Most people agree that a potato is good food until you fry it or mash it and add salt and butter and milk to it. Then it becomes high calorie, high fat and probably less healthy. It is better just microwaved, boiled or baked, period.
Part of the problem seems to be that people understand that simple unprocessed food is best, but there are social pressures especially within families to eat otherwise. When your wife-husband prides themselves as a cook, it becomes a personal insult to them if you do not eat their food, never mind the fact that everyone in the family is overweight. Kids feel cheated if you do not take them to McDonalds, etc.
Groups like this have great intentions. Sharing recipes, etc. That is part of the live to eat mentality however. I'll say it anyway. A simple, vegetarian, low-salt, low-fat, low calorie diet high in whole grains, fruit, vegetables and fiber is the healthiest way to eat. This involves almost no cooking at all.