Walking is a definite help in this department - although it works best if it regular (daily), brisk (slightly faster than your normal pace) and sustained over thirty minutes or so. Some of it is dependent on your metabolism though.
In my presenting as male days I have been vegan for two extended periods (currently I'm vegetarian and including some dairy products, mostly non animal rennet cheese) and I can vouch for losing a truck load of weight. I had the boniest @$$ it was painful to sit on hard seats for extended periods, and needed braces to keep my pants up because the belt was too big. I ate regular and large meals but without animal fats in the diet I became rather skeletal and despite being 6'3" weighed only 9.5 stones at one stage... yes, very underweight. Still, I did have fairly good health and energy levels, for a while at least.
In terms of foods, I'd suggest looking into some of the vegan macrobiotic practices... dropping processed foods (especially white flour products), sugars, alcohol and too much totally raw food, adding whole grains and pulses, using sea vegetables, sea salt, miso and shoyu in cooking, eating seasonal vegetables... etc. I've seen numerous people drop multiple pounds on that diet. Some (myself included) got a bit fanatical... (hence the underweight experience).
I also found that regular strong dynamic yoga classes was a good exercise practice for weight loss. Yes, I was a 1990s new age hippy!
