How many of the nutrients we need could be delivered through the lungs? The benefits are many, at least as a niche item. You could strap on a mask and breath some nutrient steam, all the while working, reading, writing, jogging, sleeping, whatever. Inhalants are delivered direct to the blood-stream, so the nutrients could be used quickly, and the balance could be tuned to be very efficient.
One problem I forsee would be lung damage, such as smoking causes. However, vaporizing most drugs is fairly benign, so I imagine we could find a way to strip the aerosol of harmful components. It probably couldn’t be the sole source of nourishment (I think your stomach would atrophy), but it could be used every so often when special circumstances call for it.
Um, no thanks,I just can’t imagine a life without real food, I don’t think I want to.
It wouldn’t be life without regular food, but life with both regular and breathable food. You wouldn’t use it all the time, but if you were really busy you could use it to improve you efficiency.
I think you might run into a whole bunch of molecular restrictions. Many, if not most complex molecules (food) simply couldn’t enter the bloodstream. We need Xunzian in on this one.
Now if you could figure out how to breathe sex… 
Isn’t that what fast food restaraunts and frozen foods are for? Just how fast to you need to move Carleas? Ohhhhhh wait you are a student are you not? That would explain why you need to be more efficient
Pressure sucks.
The biggest problem that I can see with it would be tripping the hunger response. For example, our bodies don’t recognize liquids as a valid calorie source. Think about sodas, they have an incredibly amount of calories in them, but you can drink a Big Gulp of Mountain Dew that has around ~3,000 calories, but you won’t feel ‘full’ after you’ve drank it. I have to imagine that inhaled food would work more-or-less the same way. So you’d have some nutrients, but you’d still be hungry. I have to imagine most people reading this site generally don’t have to take a meal because they are horrifically malnourished but rather because they are hungry.
I’ve been wanting to exist without the need to eat for many years now, but have found foods that give maximum satiation with minimal amounts of eating, instead: which brought me to thinking about the claims of Gurus who purport to exist for years without the need for food or fluids. 