Well, we do know from interviews with the Cohens that they thought Jeff Bridges was too fit for the role of the Dude at first, and they asked him to bulk up a bit.  I suppose that means that whatever the Dude eats leaves him generally healthy, but pleasantly plump.  I think it's safe to assume that he doesn't binge on junk food, but he probably doesn't count calories or fret too much about saturated fat either. 

Keeping in mind that the Dude enjoys doing a J from time to time, it wouldn't be out of character for him to get cravings for salty snacks with some frequency.  Trying to "read" the Dude in my mind, I get the feeling he likes a lot of refined carbs (bagels, pizza, pretzels, chips. 

Of course, we already know he stopped at the In & Out Burger after the uh...what have you; but that seemed to be more Donny and Walter's idea.  The dude was detachedly staring out of his broken windshield the whole time.

What exactly does The Dude eat??

In histoy we know Jesus (not "The Jesus") ate fish, bread, fig newtons, and wine. Buddha ate alot, then didn't eat, then he ate just right. Jewish and Muslims "don't" eat pork and cow ass. Most followers of these religions try to replicate what their dieties ate so they can feel closer and have a holier connection with them.

So we know The Dudes mothers milk is Caucasian/White Russian. I thought I saw a bag of Frito's somewhere. Some Chinese containers, cup o noodles. Anything else?

Then perhaps we can create the perfect Dude diet. Or whatever, just eat what's within arms reach. But we know that a decent amount of effort must go into searching out the the perfect half and half.

Well, I do believe they went to the In & Out burger, and if I'm not mistaken the dude had his hands snackin in a bowl of bar mix nuts. It's safe to say if Walter and the Dude stop at the diner, they likely eat at them too.

Oat sodas are a good source of caloric intake too.

I'm pretty sure the dude diet is whatever you want it to be. I will say that I heard a quote here once that said that the truly lazy man stays in shape so that he can easily move from couch to couch. Or something along those lines. And I don't think i've ever met a truly hefty dude before.

My favorite food is pizza. If there is something more dude than that, i've yet to find it.

I have to say I think I agree with Meekon on this point; it seems a little silly to me to worry about diet (beyond "don't eat McDonalds twice every day," or other obvious health-related stuff)

Especially in the light of my Roman Catholic upbringing. ("NO MEAT ON FRIDAY." "Uh, okay. What'll we eat then?" "FISH." "Fish?" "YES. FISH." "Fish is meat." "NO ITS NOT, ITS FISH." "So, uh, the meat of a fish isn't meat?" "RIGHT." "Riiiiiight...")

All that said, I recently tried a fried peanut-butter-and-banana sandwich.  I can see how Elvis might have been inclined to eat himself to death on 'em.  A little messy for my taste, but it was a fun treat.

Salted Peanut Chews dudes! Simple to make but oh so "nasty"!
http://www.tasteofhome.com/Recipes/Salted-Peanut-Chews

If you want to eat like someone to be them try this on for size:

http://www.funnyordie.com/videos/bfb12aea47/charlie-sheen-s-winning-recipes

This may sound a little corporate or what-have-you, but I have to say I am a *massive* fan of Dream Dinners. You show up, they have everything ready to go, you don't have to clean a thing, and you just throw the frozen shit in a bag in your crock pot and bam. Dinner.

I must also say that my breadmaker produces quality Dude Food. Chuck a few things in and a few hours later, warm bread.

Dream Dinners + Crock Pot + Bread Maker = Laziest Cook ever with Delicious Dinner.

It is quite a neat idea in a lot of respects; we used them for awhile  - then it got a little too expensive. I don't recall cooking anything there; generally you just go around the kitchen weighing and bagging up the ingredients for each recipe you have purchased. We found a cheaper place where it was pretty much the same thing but you also had the option of of having it all bagged up for you (which we favored) but eventually that got a little too pricey, too. Pretty cool idea - can't recall where they sourced their food - you might want to look into that - generally good quality.