Diet helps a lot, but exercise is needed too. You will look saggy (trust me on this one) in parts if you don't tone. Plus 20min of cardio 3x a week will burn it off faster too. That doesn't have to be running. That can be using an elliptical, dancing (I do this when I'm cleaning house), walking fast, roller skating, biking, even going up and down stairs a ton. Also toning at home is easy. You can get some 2.5lb weights for each hand and do arm toning exercises, pushups too. For legs and butt there are things all over the internet that you can do at home. The tummy is a bit harder FOR ME to tone (but that is because I lost a lot of weight after delivery and have a "mommy tummy" w/ excess skin...a lot of it). But, just sucking in your tummy for about 30 seconds a lot during the day will help. You arent just working on getting smaller...you are working on getting HEALTHIER. It takes a lot of time to lose weight. If you do it fast you could end up just reversing the effects later. Its not a diet, but a lifestyle change. To keep looking great you have to make that your way of life. I'm far from great, but I'm going to keep going till I get there.
Dont give up. Take 30min a day at least and do some toning and you will work toward a better you.