Walking immediately after meals is a bad idea, it can result in acid reflux and indigestion. However, walking about half an hour after meals is known to be good for you. Researchers in the Department of Exercise Science at the University of South Carolina have found that walking post some rest after meals is a good way to burn energy.
The point to note is when to walk, you should ideally walk for about 10 minutes and only 20-30 minutes after meal to prevent acid reflux and stomach upsets.
A good leisurely walk after meals helps set the metabolism to a good level, gives your muscles a stretch and is a better option than promoting fat deposition by lying on the sofa watching TV. Mayo Sleep Clinic even states that walking post some rest after meals help you sleep faster and deeper.