Diet and exercise helped me lose 35 lbs. and keep it off for the past 10 years.
You can lose weight with diet alone, but if you're out of shape you still look like a blob... only smaller. You'll also be more prone to put the weight back on.
You actually need to change your lifestyle. Instead of sitting in front of the TV or computer every night you will need to execise. You'll also need to eat healthier. I lost the weight with a low fat diet... low or no carb works for others.
Find one that works for you, and stick with it!!!
You'll feel much better with exercise, and it will help you gain back a more youthful appearance!
Hope this helps.