Difference in cost for weight loss

I’m 40 and 250 lbs. I’m extremely motivated to lose weight (have lost 10 lbs so far from 260) and think if I keep it up I could get down to 160 or 180 lbs by end of this year.

I recently tried applying for life insurance but the company has been a pain to deal with, as I’ve been 3 months in underwriting and they are moving so slowly that I think I’ll stop the process with them. I read a lot of bad reviews of them so it makes me edgy that if I did die, my wife would have a hard time actually getting a payout.

I am thinking I’ll wait until I am at a more normal BMI – ideally normal range or at least on the low half of the overweight range.

In theory if I lose a bunch of weight by my 41st birthday, should I go ahead and apply for life insurance right away, or how long should I wait?

On one hand, getting it sooner seems better because life insurance gets more expensive the older you get. On the other hand, if insurance companies see that I’m 160 lbs but that I was just at 250 lbs within 1 year then they might not be jumping to offer me a good rate because they might assume I’ll gain the weight back especially as I have a history of yo yo dieting.

If I wait 5 years to get it, then maybe they will lower their rates if they see I maintained the weight loss, but then again as a 45 year old, it will get more expensive. Also of course if I die in the next 5 years then my wife will get nothing.

So basically my questions are:

How long do I have to maintain weight loss in order to get better rates? Is it worth waiting or does the cost of applying at an older age start to factor in more?

Or, is it better to just get it now and then refinance in the future once I lose weight?