Coffee drinkers live longer. Actually, make that shorter. Saturated fat is actually good for you. Wait, scratch that — it’s actually not so great. Confused yet? You’re not alone, according to the New York Times, which runs down why food and exercise studies often give such wildly different results. “The problem is one of signal to noise. You can’t discern the signal — a lower risk of dementia, or a longer life, or less obesity, or less cancer — because the noise, the enormous uncertainty in the measurement of such things as how much you exercise or what exactly you eat, is overwhelming.” To add insult to injury, there’s no gold standard guidelines that everyone agrees on to measure aspects of certain lifestyles, meaning we have large bodies of studies that no one can reproduce. In short: “We don’t know how to measure diet or exercise,” according Barnett Kramer, director of the National Cancer Institute’s division of disease prevention.