Don't just wait. Buy him pastries. Cakes. Big heaping piles of extra cheese fries at lunch.  Don't just wait: tip the scales in your favor. Or if this is too much personal expenditure, encourage more company picnics, more company-paid-for food expenditure. Encourage him to gorge himself: "you only live once, right?" Push him to the brink and then let him sail right over the edge.  Your sanity and peace-of-mind will thank you.  Remember, friend: DEATH to HAMS.