Exercise is good regardless, but the walk isn't achieving anything really regarding noticeable weight loss. It's 90% diet.
And basically, by diet, it's restrict/stop eating. And once you get in your head, that not eating in a controlled way is fine, it's quite a powerful thing. We're told, "you can't just not eat, it's not healthy....starving yourself will get you nowhere" and so there's this big stigma around it.
You'll see from PP that intermittent fasting has worked. Fasting simply another word for not eating, but "fasting" is socially acceptable.
So, work out what works for you. It's a lot easier to not eat than restrict your food. If I have no breakfast, that's fine. If I'm meant to just have a poached egg on toast, I'll be hungry, and probably make another round.
Something that has really worked for me, is the 12hr concept. There are 12hrs a day you can consume food, and 12hrs you can't. If you wake up and have breakfast at 7am, the last time you can eat food is 7pm. Because it's typically not our breakfast/lunch/dinner that is the problem, but all the evening grazing.
Like anything, if you eat 3 gateaux a day on the justification "well it's in my approved 12 hours" it's not going to work. But you can eat pretty normally. And you're asleep for a large chunk of the 12hrs where you don't eat.
Also, how much are you drinking? Every time you feel a bit peckish, do you have a cup of tea first? I drink a tonne of hot blackcurrant. It doesn't fill me up, but if I'm getting a bit hungry, and I have a hot drink, I tend to last another hour before I need to eat something.