There are studies done on aborigine people and they have perfect dentition and mouth health because food with sugar is extremely rare in the wild (wild fruits taste bitter, not sweet). I wouldn't be surprised if chronic bad breath is something that simply doesn't exist if you live outside/lived before civilization.
The explorers who studied Eskimos/Inuit in Northern Quebec have reported the same thing. And when Inuits are introduced to processed food, their health decline.
http://en.wikipedia.org/wiki/Weston_Price
http://www.journeytoforever.org/farm_li ... cetoc.html
"In his studies he claimed to have found that plagues of modern civilization (headaches, general muscle fatigue, dental caries or cavities, impacted molars, tooth crowding, allergies, heart disease, asthma, and degenerative diseases such as tuberculosis and cancer) were not present in those cultures sustained by indigenous diets. However, within a single generation these same cultures experienced all the above listed ailments with the inclusion of Western foods in their diet: refined sugars, refined flours, canned goods, etc."
I recently watched "Food inc",
http://www.imdb.com/title/tt1286537/ excellent documentary. There's a snippet that i found pretty interesting, this scientist was saying that many cows who are put on a grain diet develop serious bacterial diseases such as e.coli and must be treated with antibiotics. But if they put the cows back on grass (which is what they should be eating), the bacterial activity in their stomach decreases by 80% only after 5 days. Could be a coincidence but my BB decreases by that much if i stop eating grains. I wouldn't be surprised if perfectly mimic'ing an indigenous diet would result in fresh breath. Now the problem is that the meat, fruit, etc in supermarkets have all been domesticated and are nothing like in the wild.
Not to be a pessimist but if the beef industry which literally has billions of $ to their disposal couldn't figure out how to prevent bacterial proliferation from happening in cows' stomachs.. those of us with digestive halitosis (Type 3?) have no chance, we're only clueless people on an internet forum :/