Until I was 50, I put weight on at Christmas and on holiday and lost it afterwards and my weight was still what it was in my 20s, and well within all guidelines.
From 50 my weight just crept up slowly and inexorably. I used my usual weight loss methods without effect. I must have cut my food intake by at least a third and my exercise level shot up because I retired early and DH and I promptly took on a major renovation project, house and garden, so I was doing garden clearance and decorating etc 5 hours a day for months at a time. Weight gain stopped after about 10 years by which time I had gained over a stone and a half. But nothing I did could reduce it. I was reduced to trying fad diets, anything, to try to lose the extra weight but without success.
Then 5 years ago, at the age of 70, the 5:2 diet came on the scene. I went on it and in 4 months I lost 2 stone and have not regained it. Just back to my usual pattern of 3-4 lbs at Christmas and after holidays, which I can lose within weeks. I follow the 6:1 maintenance program and 6 days a week eat what I want, as I want, without worrying about my weight and certainly never going hungry.
However as I am now nearly 2 inches shorter than I was before the menopause, I would like to lose another half stone to keep my BMI comfortably in midstream.