BBT053 wrote: I've not asked the boys at the gym in detail but there's an argument that fat round the middle is hormone related. ...
Hormones do have an effect.
Paraphrasing from Gary Taubes' book, Why We Get Fat on the topic of menopause, page 119:
"LPL [lipoprotein lipase] is the simple answer to many of the questions about why men and women fatten differently.
In men, LPL activity is higher in the fat tissue of the gut, so this is where men tend to get fat. As they age they secrete less testosterone (which suppresses LPL) so they get more fat.
In women, LPL activity is highest in fat cells below the waist to fatten hips and butt.
After menopause, women's LPL activity catches up to that of men, and so they tend to put on excess fat there too."
Note that insulin and estrogen level also affects this, in that higher estrogen levels limit fat deposition. Menopause reduces estrogen levels, which means more fat can be deposited.
(Hopefully I abbreviated this section of this book accurately.)