well, the thing is, fatty was right. maybe not in the percentages, but the fact that the cost of eating out (black) matched wages (dashed red)-- specifically wages for individual, non-supervisory employees in mostly very blue collar jobs. the other lines are cost of food at home, and blended total food spend.
you didnt specify a timeframe but mentioned "previous twenty years" so i rounded up to a nice 2000 start date.
switching gears to talks of the "middle class stagnation/shrinking", these might rile people up a bit:
this is from the Congressional Budget Office's late 2023 publication of Distribution of Household Income, pages 26 and 28
and then this one...if you consider 20-80th income as middle class, its size has been constant.
in fact if you segregate the middle three quintiles as working class (20-40), middle class (40-60), and upper middle (60-80), itll show the "middle" did shrink because they promoted upwards into the upper middle!