Why do we kill ourselves with food and drink?

So I’m lying in bed, scanning through my body.  It’s the start of a meditation practice I picked up from Arnie Mindell but today I’m not meditating, I’m just observing.  Yup, the torn muscle in my arm is still twinging a bit and there’s my Achilles putting up its, er, ankle to wave its discontent.  My jaw is clenched and my shoulders are tight (I’m not sure I relax even when I sleep).  And my arms are aching from yesterday’s kettlebell class (but that’s a good ache). ...