Re: I have walked my way to massive weight loss!
Absolutely brilliant work.
You have done what very few manage to do exceptionally well. You have looked at your goals realistically and long term, the only way to be truly sucessful.
Walking, swimming and fornication have one thing in common, they use all the muscles in the body, so you are already working your upper body.
Weights can be carried to enhance this but I woudl suggest having a hip bag to put them in if needed.
At your weight you are already having to move a lot of mass every time you move so the chances are additional resistance is not required. However your body is used to this weight being in major areas like around your upper arms and less so the further down your arms you go. Adding wrist weights or carrying light dumbells will put pressure in areas you are not used to for such long durations. Initially your wrists, then your elbows to compensate and even your lower back if you start changing the way you move your arms.
This is not saying don't do it, quite the opposite, for short distances this will be great, but as soon as you feel discomfort you will need to be able to put the weights somewhere safe, like a hip bag. Over time you will be able to bring them out of the bag repeatedly, then at some point maybe for the full time, but you are unlikely to be safe trying to do this for the full 4 hours straight away.
Weight training would be good for you in a few ways. muscle burns energy even at rest so it would aid your fat loss, and most of the work you are doing will be building your legs as they are supporting your weight.
You are evidently intelligent enough to already know this but take it steady at first and increase gradually with this style of training. I wouldn't normally say this but at first don't bother training your legs on resistance work, you are doing really well on the walking and the last thing you need is to do something that makes this difficult. Over time you will be able to encorporate this into your regime.
Well done again!