As long as you're in negative energy balance, you'll lose weight and fat. It doesn't matter how you get there...just get there. Walking for an hour twice per week will burn you an extra ~800 cals per week...and that's the number that matters. 800 cals per week isn't big, but it's something...and it's a slow enough weight loss that most of it will probably be fat if everything else is up tp par (diet, strength training, rest, etc...).