I've been watching Man Versus Wild and I've noticed no matter what wild environment he's in, he always finds more protein than carbohydrates. He finds it relatively easy to find protein to eat, and very difficult to find any carbs to eat.
Our ancestors for millions of years of our evolution were in similar environments, and not until the invention of agriculture would carbohydrates become abundant.
But agriculture was only a brief moment ago in evolutionary time, so the brain mechanisms causing our cravings are not adapted to our current situation (a constant availability of abundant carbs).
In other words, our bodies and brains are assuming protein is our mainstay, so when our brains want to make more serotonin, we crave carbs, not protein.
Anyway, as I said in the article, What Goes In, we have a simple rule to follow that doesn't require counting calories or weighing food or keeping track of grams of protein: Always mix carbs and protein in every meal (and in every snack) and you'll be getting the maximum amount of tryptophan into your brain. Your brain will have what it needs to make enough serotonin, so you'll feel better more often and you won't have an unnaturally voracious appetite.
All the research is fine and dandy, but the real test that counts is the one in your own life. Give it a shot and find out what happens.