middle-age spread vs potbelly

middle-age spread

noun
  • Belly fat that develops in middle age. 

potbelly

noun
  • A large, swollen, or protruding abdomen; a paunch. 

  • A potbelly stove. 

  • A Vietnamese Pot-bellied pig. 

How often have the words middle-age spread and potbelly occurred in a corpus of books? (source: Google Ngram Viewer )