Is the french paradox really true that one beer a day but no more lowers risk of diabetes and heart problems ?

True but complicated: On average, coronary artery disease, stroke, and death from all causes are somewhat more common in people who drink no alcohol than those who drink modestly, the equivalent of 1-2 glasses of wine a day. But risk rises rapidly with more than that. It isn't known if non-drinkers can lower their own risk by drinking modestly. But heavy drinkers almost always have improved health when they cut back.