Nutrition researchers know a lot about diet. Or at least what constitutes a good diet.
The reason you think “they don’t know” is a media ecosystem that hypes weak minor contrary results that usually disappear in further research and an entrenched trillion dollar food industry that spreads misinformation to get you to continue eating the foods they sell that have the highest markups, such as processed foods, meat and dairy.
The reason you think “they don’t know” is a media ecosystem that hypes weak minor contrary results that usually disappear in further research and an entrenched trillion dollar food industry that spreads misinformation to get you to continue eating the foods they sell that have the highest markups, such as processed foods, meat and dairy.