You can keep your weight within bounds without having long lists of things you do not eat and making your life a misery. The number of things on my avoid for weight reasons is 0. I have food likes and dislikes, but so do we all. I do not snack because that is the way I was brought up. Three meals a day and no eating between meals.
I also do not have a sweet tooth. I have a box of biscuits in the kitchen for when visitors come. They have been there months and I have dipped into it once and eaten two biscuits, after a long very busy day. Most of the time I forget they are there.
It is the same with exercise. I do agree that keeping active helps to keep your weight steady, but you do not have to drive your self to relentless daily activity. I am a walker, I have walked by choice almost every day since my early 20s. I have walked to work, to the station, got off buses and tubes one stop early so that I could walk. When I drove to work I would go out for a walk at lunch time. I enjoy it and miss it if I do not do it. I have always been a fidgetty person. I rarely sit down for more than 10 or 20 minutes without needing to get up and walk round the house and my family tell me that when I do sit down I tend to jiggle my legs and keep moving around on my chair. All this uses up energy.
I think the answer is getting yourself into the right frame of mind, check what makes a healthy diet, keep portion sizes under control and keep active.
The most important of those is in the mind and I suspect more people would lose weight if they could see a counsellor. I suspect the reason Slimming World works so well is not the recipes but that the Counsellor, and that is what SW calls them, keeps up a constant dialogue with Slimmers to help change their mental attitudes to eating, as much as the nutritional help they get.