that's actually more or less true. your stomach has a pretty delicate balance but it's pH normally is around 7 (neutral). when you eat something basic, like raw foods, you upset the balance and your body produces stomach acid to counteract it. the problem is, meat is slightly alkaline, which has the effect of keeping your stomach more acid then normal and it does eat away at the lining. have you ever noticed how people that eat a lot of meat have a big belly? that's not all fatty deposits, but their stomach lining has been eaten away and stretched so it's no longer tight, allowing their organs to sag. this is why ethiopean children have bloated bellies, the basic protein feed mix they're given actually has a worse effect than meat.