I don't think anything needs lifestyle change. If you can do something in a consistent manner, you can definitely reach the target.
You can do simple things to loose weight,
1. Eat slowly
(Many chubby people are fast eaters. Since they are eating fast they tend to eat more than their stomach needs. If you are a slow eater you will feel that you have eaten sufficiently. But for fast eaters when this signal comes from their body they already have eaten too much)
2. Give up your lazy activities and be active.
(You can do little things to make your body active. Walk to your office instead of driving the vehicle into the office. etc.)
3. Eat fruits and vegetables more.
These are some of the guidelines to reduce your body weight.