Exercising doesn't particuluarly make you lose weight, but it tones up what it already there so you lose alot of inches.
If you want to lose weight, I follow Slimming World and it's more of a healthy eating plan rather than a diet. It gets you to focus on eating lots of fruit, veg, lean meats, fish and other proteins (eggs, beans, etc.) whilst eating pasta, rice potatoes in moderation.
you get a certain amount of 'Syns' per day that you can use on what you pleased - sauces with meals, crisps, alcohol, chocolate, etc.
And a daily allowance of fibre and dairy.
I know lots of people who have lost weight with Slimming World without doing any exercise. I did my first time round. I lost just under 2.5 stone and then started to exercise.
I've seen people lose up to 5 stone without doing any exercise, except for maybe the odd walk here and there, but nothing more strenuous than that. It is possible
If you don't want to join a particular plan as such, I would advise you to do the usual - limit your intake of fatty and sugary foods, try to snack on fruits between meals, load your meals with protein and veggies rather than pasta, etc.