What a miserable way to spend one's twilight years. I've heard it all before, some from doctors twice my size!, and the only real notice I've taken is to up my exercise routine. I spent the last few years of my job sat behind a desk and following retirement did much the same causing me to balloon to 18 stone. My wife and daughter bought me a Fitbit exercise watch about 18 months ago and since then I walk every day, usually 4 to 5 miles. I even bought myself a treadmill for the days when the weather is bad. I lost 2 stone so far and not stopping there. I still enjoy a drink (or two ) but restrict it to 4 days a week, I still enjoy cakes and the odd biscuit. I have never smoked.
Serious diet and exercise is for the young. At my age (75.5) I would rather enjoy what's left by doing what I enjoy. As the man said "moderation in all things"