I was 230 when I retired in 2002. (Pretty high for a short guy, 5′-7″)
This morning, 151, where I have been the past year or so. Below 160 for several years.
I first hit 230 in 1980. Between 1980 and 2002, fluctuations up and down between 190 and 230, maybe occasionally 180.
So:
Exercise works. There are a gazillion scientific studies on this, nearly all of which say exercise is useless. I disagree, the more access to activity I have, the better I control my weight. I currently ride my road bike about 3 hours a day, obviously not possible while I still worked.
CICO, calories in, calories out. The laws of Conservation of Energy and Conservation of Matter and Thermodynamics remain true. Calorie balance counts.
My experience is bulky foods like raw vegetables are good for appetite control. I do not find fatty foods satiating, they make it easy for me to overeat.
Nutritionally, fat soluble micronutrients are important as is omega three, so I do eat a lot of fatty fish, several eggs a day (the high omega three kind) and a couple of ounces of cheese. Other than that, I try hard to minimize other fats. (Fat makes me fat.)
I think it better to eat significantly more than the RDA of protein.
Some controversial opinions:
Vegan diets suck, there is plenty of evidence of severe long term bad health effects on most vegans.
Extreme low carb high fat diets suck. This is obviously difficult to study, and I am not aware of studies that show ill effects. I do, though, find it hard to believe that going ketogenic is not very long term unhealthy.