walk a lot and obese faster

I am obese. I weigh around 245. I want to do a long fast, the thing is I walk dogs about 2 hours of walking a day or more.
I can't rest in bed all day.
From what I read around here and there, obese people can have more energy while fasting. So, it shouldn't be a problem?
I read an article, I can't find it, about an extremely obese man who went a year fasting.