What I do know about it is that there are very conflicting views amongst professionals as to what helps and what doesn't.
Incidentally, on the diet thing, a few years back (four or five maybe?) I went on an internet binge on and around the topic of fat storage, gain, loss etc. It left me convinced that it's a multifactorial thing, very individual, and that the standard advice for the last few decades has been too skewed by big-company and government interests. (E.g. pushing high carb, low fat, which made sense both in terms of pushing highly processed junk food and also in persuading people in America during the cold war to rely on crops that were American-grown like corn/maize.)
In the end, I reached the opinion that our society is over-keen on fat-shaming whilst under-helpful to people who are over-fat. It's not helped by an obsession with weight, which is a useful everyday proxy, but to compare, I'm over-fat and under-fit but weigh 2lb more than I did when I could do PT with the paras. Yes, that is two pounds not three stone. Back then I was 'overweight' on an NHS chart but had a small belly and loads of muscle.
Likewise this year, I dropped about two and a half stone, mainly fat, just by changing my diet, not by 'dieting', but I'm putting some belly fat on again, and I'm pretty sure that for me it's currently wanting biscuits.
(I wish there were a way of persuading my doctor to increase my thyroxine. He'd save me hundreds a year on my heating bills as well as reducing my fat.)
Recently, I've started looking at it again. I'm particularly interested in what Giles Yeo is saying about how individual the issue of storing and using fat is, and how it's not simply calories in, calories out.
The reason I say all that is that my weight, fat, size etc. have wildly yo-yo'd over the years and I've found it healing to trust my own instincts on when it's junk-food & sugar bingeing (which I do), when it's medication (olanzapine sent me from to size 12 to size 26), when it's practical food shortage (4 stone lost in 10wks in a psychiatric unit) when it's thyroid (last reduction, extra stone in 2wks) etc.
On the blood pressure front, my own blood pressure is higher than I'd like, though I haven't measured it for some time, and I'll be reading contributions to this thread, because it's a reminder to me to work on it, though I doubt I'll ever get back to the blood pressure of my twenties, 80/50 when relaxed, 90/60 when stressed. (Yes, eighty over fifty when chilling out in barracks, preparing for my combat med tech exams.)
(Edited re weight - just nipped upstairs, took off my outer layers and weighed myself.)