Facts you should know
Why do we feel drowsy after eating a large meal ? (01 Sep 2014)

Contrary to myth, it's not caused by blood being diverted from our brain to our stomach. The drowsyness is partly because our body activates a " rest and digest" mechanism (the opposite of "fight or flight" response) and partly because high carbohydrate meals increase the levels of melatonin in the brain, which makes us feel sleepy.