It seems insane, but people who are practitioners often don't follow current research. As there are a lot of programmers in this forum, I think an easy way to

It seems insane, but people who are practitioners often don't follow current research. As there are a lot of programmers in this forum, I think an easy way to show this is to look at your fellow programmers. How many read and understand the current scientific papers in their field? Even relatively simple things are completely overlooked. For example, how many people who do AB testing can understand the statistics of what they are doing? We've more voodoo recommendations in our field than you can shake a stick at. Our field isn't especially lax in this area. Probably just the opposite. Most people just don't keep up. Ideas are formed in university and never change. I worked as an EFL (English as a Foreign Language) teacher for 5 years. None of my colleagues knew anything about language acquisition theory from the last 60 years (they didn't even know who Noam Chomsky was!!!). Even worse was their understanding of the current state of the art in education research. At least for language acquisition they vaguely knew people were doing research at all. For education, forget about it. As you say, nutrition is a hugely complex subject and research is still in its infancy. However, it does not surprise me at all that working nutritionists will hold on to old ideas until they die -- often passing those old ideas to the next generation. I fight against it, but I expect I will do the same as a programmer too ;-)