This may happen because you are eating foods that are too heavy for you to digest or perhaps you are eating too much food at one sitting. There are many reasons this could be happening, however, there is one cause for this post-digestion heavy feeling that is often overlooked. It is not connected to the food that is on our plate, but rather what is in our drinking glass. The first thing they give you when you sit down at a meal in most restaurants in the US is a large glass of ice water. By the time our food comes we have already consumed one or two glasses of cold water. According to Ayurveda the 5,000 year old holistic system of medicine, when we drink cold water we weaken our digestion by dousing out our digestive fire (agni). Imagine that you are sitting around a campfire roasting marshmallows and someone comes by and dumps a bunch of wet logs over the flame. The fire would get smothered and become very weak or disappear. The same thing happens to our internal digestive fire when we drink a lot of cold water.
I used to think I needed to drink 8-10 glasses of water a day. I would carry around an enormous bottle of cold water with me and chug it throughout the day. Of course, I was just trying to do what I thought was best for my body. I thought I was flushing out the toxins in my body with every glass. I had no concept of Ayurveda at this time in my life, however, now I can see why the digestive disease I had suffered from for so many years was just being aggravated by my excessive water intake. I was literally drowning in all of the water I was drinking. Now I understand that in order to destroy ama (toxicity), one must kindle the agni (digestive fire). Toxicity cannot be "flushed out", it needs to burn.
It can help to think about it like water flowing through a metal pipe. Cold water will cause the pipes to contract, and hot water will cause the pipes to expand. If we want to keep all of the channels (srotas) in our body open and flowing, it is important to not constrict them by drinking ice cold water.
I never imagined that changing the way I drink my water could have such an impact on my physical health, but over time I have witnessed the effects first-hand. Try sipping a small amount of warm or room temperature water during your meal instead of drinking excessively before or after. According to Ayurveda, it is best to sip water throughout the day as you are thirsty as opposed to drinking a lot at one time. Its helpful to carry around a thermos with you, so you can enjoy hot water throughout the day. I also ask for room temperature water or order hot water with a lemon when I go out to eat. Be your own judge, try changing the way you drink water for a week and see how it makes you feel. You may be surprised at how amazing you feel after making this simple change.