If ever you heard not to eat burnt food because it was carcinogenic, AGEs are to blame. Like when food gets brown or burnt, that's because of AGEs.
Anyway, your body produces them internally all the time, and having a controlled exposure to AGEs occasionally through cooking seems to benefit how your body handles them.
If anyone wants to read more on it, there's a lot of info at beyondveg.com of the whole raw vs cooked debate.
Yes, I think there is a huge difference between glycating your own proteins with dietary sugars (which can lead to diabetes and Alzheimer's) and eating glycated or charred protein byproducts such as benzopyrenes. The difference is night and day: the former is damaging your own tissues, the latter is stimulating your xenobiotic metabolism to gear up and process an incoming raw material.
It's true that benzopyrenes (charred protein byproducts) have been found carcinogenic in single cell assays. But these reductionist assays leave out any system-wide metabolic defenses! Interestingly, while benzopyrenes can cause cancer at high doses, they also induce Cytochrome P4501A1, a oxygenase enzyme that enables xenobiotic detoxification as part of the Phase I enzyme system:
http://www.annualreviews.org/doi/abs/10.1146/annurev.pharmtox.39.1.103If you combine upregulation of P4501A1 with induction of the Phase II system (via Nrf2), then you generate a protective effect. In other words, eat some good colorful veggies along with your overcooked meat or burnt toast! Other hormetic stresses like intermittent fasting, intense exercise and cold showers are probably just as good as the veggies.
I've always been skeptical of the idea that you shouldn't eat charred meat because it's carcinogenic. Seems to me that our ancestors would have been much more perishable than they seem to have been.
