I agree with Pradeep , There should one hour gap to do work. In the mean while after eating you should walk for 15 minutes, so that the digestion will be easy.
After eating, the major flow in our body is directed to the digestive system to aid proper digestion and for absorption of nutrients from the food that we ate. If we work out immediately, this blood flow gets directed to our heart and the limbs and hence disrupts proper digestion and since the nutrients are not absorbed in the blood, it is as good as eating a lot of junk!