Diet and exercise go hand in hand for a healthy, toned body.
If you are new to exercise a personal trainer or physical therapist can do so much if you will listen. Whether your knees or back are problems, or just need to lose weight and strengthen joints before they break down, doing the right balance of exercises to get everything in balance will make quicker gains for you than just working out, although cardio using good posture is a great start too. But if you work the muscles right and build them up in a balanced way, you burn more calories when you do your cardio. You can learn a lot from YouTube with just basic equipment for Pilates. Bands are cheap. An exercise ball is great for abs. Always do squats and lunges with proper form. You don't need q pilates mat for pilates or yoga if you have an area rug and a big towel.