"You are what you eat."

Check out the "you are what you eat" photo exhibit at http://www.markmenjivar.com/.

Meaning

(excerpted The Phrase Finder)

The notion that to be fit and healthy you need to eat good food.

Origin

This phrase has come to us via quite a tortuous route. Anthelme Brillat-Savarin wrote, in Physiologie du Gout, ou Meditations de Gastronomie Transcendante, 1826:

"Dis-moi ce que tu manges, je te dirai ce que tu es." [Tell me what you eat and I will tell you what you are].

In an essay entitled Concerning Spiritualism and Materialism, 1863/4, Ludwig Andreas Feuerbach wrote:

"Der Mensch ist, was er ißt."

That translates into English as 'man is what he eats'.

The actual phrase didn't emerge in English until some time later. In the 1920s and 30s, the nutritionist Victor Lindlahr, who was a strong believer in the idea that food controls health, developed the Catabolic Diet. That view gained some adherents at the time and the earliest known printed example is from an advert for beef in a 1923 edition of the Bridgeport Telegraph, for 'United Meet [sic] Markets':

"Ninety per cent of the diseases known to man are caused by cheap foodstuffs. You are what you eat."