Are you thankful for your life? For what you have? If the answer is yes, then it's really great. But if you are not and don't feel grateful for everything, maybe you should give it a second thought. Being grateful doesn't require much practice but it surely needs lots of passion.
I think we should look around and see how people are living their life. In this regard, we have to concern downwards. For me, if I have a full functioning body I should feel thankful for that, if I have assurance for my next meal I should be grateful for that and the list is too big. A family, a friend, a shelter, an earning source everything is a source of feeling grateful. We have to remember that, many people out there don't have this life. They are struggling every single day for their dysfunctionality, inability and many more.
Practicing gratitude is so much helpful to keep our peace of mind. It brings happiness. And not only our mental happiness, we certainly can be physically well. The more thankful towards our life the more we will be a concern to take care of our bodies. We will be more focused on our body functionality. Also, I think that as our brain has a direct connection with our body, so as thankfulness brings positive energy it will certainly bring positivity to our bodies. And these things actually affect what we eat, how we eat and everything related to our body. It's like growing day by day just by feeling thankful for our life.
That's the reason, I believe we should practice thankfulness in our everyday life. It's not like you pray for it or talk about this. It's like an inner feeling which boosts our life energy and thus makes our life better.