I can't talk about weight loss with my DH either ... to him, it's simply eat less, move more, and there's nothing else to it. Fortunately he's never hounded me about it relentlessly (probably because he could stand to lose about 50 pounds himself.
Now, I'm not knocking the surgery path -- that's a very personal choice -- but if you are adamantly against it and he starts hounding you with it, you can find testimonials from people on the web. Sure, there are success stories, but there are also horror stories.
I suppose I could understand his being concerned about your weight because of its implications for your health, and I guess that's part of it. But if he's been bugging you about it for 26 years -- wow, that's just amazing. It makes one wonder why he married from you if it bothered him that much -- it's kind of like the woman who marries a guy with the idea that "I'll change him."
On the other hand, I know, after 26 years of marriage, there must be many other things about him that are wonderful, and I hope you're feeling better after venting your frustration!!!