Have refrained from adding my 2p on this thread until now, but here goes...
I don't believe that diets work - not in any long-term meaningful sense.
I was extremely overweight when I moved to England (approx 20 stone) and lost 5 stone in the first 2-3 years of moving here. This was accomplished by: DH is a relatively healthy eater so I went from lots of junk food & fast food, etc to eating a more balanced diet with lots of fruit and veg. It wasn't terribly hard - more just small changes gradually to what were very bad habits. (Most of our meals are cooked at home from scratch. We do go out for meals occasionally but we don't get takeaways any more - takeaways just seem to taste vile to us nowadays after having cooked so much for ourselves.) And I started to walk a lot vs being sedentary & driving everywhere. We have done a lot of country rambling over the years since I moved here - including two long distance walks: The Dales Way and the Cumbria Way. I was probably in the best shape I've ever been in my life when we were training and doing those walks. In any case, I am
convinced that my weight loss would not have been as much, or as sustained, had it not been for the exercise. In fact, I was nearly at my goal weight back in my 20s due to dieting alone on Weight Watchers - but I didn't develop an exercise habit back then, and the weight eventually all came back on plus more! (I got to the point where counting everything and obsessing over my next meal felt very OCD and unhealthy in a psychological sense.)
I still need to lose more weight, but fortunately the weight I did lose allowed me to come back off blood pressure tablets so the healthy benefits have been measurable. Unfortunately, I lost some ground in the past year due to a bad knee injury when we were walking the Cumbria Way (a fall) which took over a year to heal, having the flu, the death of my mom - so less exercise & lots of comfort eating.
But I am trying to get back up on that horse, and get going again - we have started walking again & are talking about training for a new long distance walk for next summer - Yorkshire Wolds Way.
I try not to pay much attention to what the latest greatest pundits are saying, because it keeps changing & everything will give you cancer & so on & so forth. Just trying to be sensible and work on cultivating healthy habits.