I hope that the question mark at the end of this tedious cliché made you click the article and read it. I've always had an issue with this statement. It is so widespread among fellow nutritionists, doctors, and of course, laymen journalists, that it is often posed (and, unfortunately, used) as the motto of nutrition science.
Where did it even come from? Probably from the ingrained cognitive abilities of the human mind called intuitive psychology. Its basic feature is the intuition about people not being things and machines – they're alive through an invisible matter, a „soul“. This precise feature is which in the past – and for some primitive nations in the present as well – led us to believe in sympathetic (voodoo) magic. This is also what leads to the wrong belief that the children whose parents are Croatian speakers will speak Croatian even if they grow up in an English-speaking family. This is also why some of us believe that the food has a „natural essence“ taken from its pastoral surroundings, which we take in by consuming it. But just like the ground rhino horns do not solve erection problems (similar objects do not necessarily share similar powers) and consuming a strong and aggressive animal's body part will not make the consumer stronger and more aggressive (buffalo's testicles in a spicy sauce anyone?), similarly the food does not make the man, more specifically – you are not what you eat.
Does that mean that what you eat has no effect on your health? Of course not. It has plenty. Proper diet, compliant with all our physiological and psychological needs, is a precondition for a long life with a lower risk of chronic disease. However, if we know that all foods, regardless of the form we consume it in, disintegrates in a certain number of nutrients (macro- and micro-) in our digestive system, we cannot not conclude that the effect of food on health comes singularly from its properties as energy source, building material, and catalyst for certain chemical changes in the body.
Of course, I don't think any of you actually believe that consuming broccoli will turn you into one, but the link to evolutionary psychology through abovementioned comparisons seemed interesting enough to write an article on. It's possible many will see it as unnecessary rant, but at least I feel better now that I've written it.