Allow me to answer this question in a slightly different way that you may expect. However, I am sure that my answer does answer your question 100%, and I do have several years worth of experience to back it up.
Looking at these two:
(A) food.com/vegetarian-pad-thai-noodles.html
(B) food.com/recipes/asian-cooking/vegetarian/pad-thai-noodles.html
- option (B) strikes me as the most useful and user-friendly one, speaking as a web site user.
Why is that? Well, because it provides additional information (value) to the page that you are on. By looking at the URL I can see that the page I'm browsing is not only about noodles, it is also "vegetarian" and also "asian cooking", and not only that - it's a recipe.
Also, as a user, I would suppose that if I remove the last part of the URL I would jump to a section front page for a whole section on "asian vegetarian cooking recipes", and by removing two parts of the URL i would jump to a whole section on "asian cooking recipes" both with and without meat.
Make sure to make those section front pages. Your users will like it.
That's
usability.
On the other hand, option (A) in terms of URL value gives me absolutely nothing. There's no logical way "from here to there", no sense of relationship as to "where I might be", no inspirational value, no nothing. It strikes me as "yet another keyword rich url" with nothing to back it up.
That said...
The single best tip about Google SEO is to forget SEO. Think about your users in stead. Do what maximizes user value. In this case, option (B).
Why is this so? Well, "doing Google SEO" means that you're always chasing Google, always acting on the latest whim, always trying to keep up, editing and messing around. And you're generally confused most of the time, and your rankings aren't very stable. Because you're acting after the fact. IOW, you're always behind.
On the other hand, if you concentrate 100% on user value, Google will study you to see what you do right and why your users are so happy about using your site. Google will even modify their algorithms to favour your site. You will know what you're doing and why, you will make very few changes and your rankings will be slow moving and stable. You will be acting, and Google will be acting after the fact. IOW, you're always ahead.
Now, don't ask "will this helpme in Google". You will always get a wrong answer, ie. a short term one.
Ask in stead, "what will bring the greatest benefit to my users". The answer to this question will have the side-effect of giving you a better rank.
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Oh, and yes... recently Google started showing my web sites in the SERPS "written as breadcrumbs with '>'s". Of course, Google made a change, not me ... just proving the point.
