We have proof that that smoking causes lung cancer. Better than that, we know what in cigarette smoke causes cancer and how it does it. We also know that stopping smoking reduces the likelihood that a person will get lung cancer. And finally we know that as smoking rates declined so did the lung cancer cases. The fact that smoking causes lung cancer is proven as well as we can possibly do. Nutrition studies on the other hand a crap-shoot. The article speaks of this. They are very hard to execute properly as these days it is impossible to control someones diet for extended periods of time. We have done such studies in the past, but we no longer do for very good reasons. These days nutrition studies rely either on self-reporting or on gross approximations from large scale data that is not entirely reliable. This makes it very hard to discern cause from effect and separate confounding factors. How do you know that it is the food and not something else in the life style of the persons that east this food? Ultra processed foods are cheap. So people who tend to eat them are not doing particularly well financially. This also means that they have poor access to healthcare, they probably work physically demanding jobs, their jobs are more likely to be performed in adverse environments, and so on and so forth. Ironically companies like Apple and Google who have a pretty good records of our lives, including what we buy, where we work and how we relax are in the best position to carry out such studies. Do we want them to do that, and under what ethical guidelines will this data be accessible?
