"Double whammy" is a phrase used to describe a situation when someone is facing two negative or difficult things happening at the same time, making the impact stronger or worse than facing just one. Full definition
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I'm sorry to say that I haven't researched this yet, but it does seem like a high carbohydrate / high sugar diet on the way towards type 2 diabetes would be a continuous double whammy for the whole pancreas, including the beta cells. (idmprogram.com)
It actually made his PFA and FWA Player of the Year double whammy in 1999 all the more impressive considering he was playing for Tottenham where mid-table mediocrity was the norm. (talksport.com)