Diet research seems like a wild goose chase and I'm not sure I trust much of it anymore. There are so many variables involved when it comes to human health that I fail to see how you can do any kind of accurate modelling on what is or isn't beneficial when it comes to food unless it has an obviously seismic effect e.g sugar, lack of vitamins and minerals etc. Whatsmore, it's plausible that something that may appear beneficial in the short term may actually be an imbalance that causes a long term response that isn't beneficial. Seemingly every food on the planet has a study showing it causes or cures cancer. Yes I'm being hyperbolic but you get what I'm saying. The whole problem is further compounded by Big $INDUSTRY funding and bribing scientists and whoever else to push $INDUSTRY_PRODUCT such as happened with the sugar lobby until recently.

People desperately want diet to behave like classical physics with an indentikit formula they can just roll out to everyone but it's just not the case. Everyone's body responds to different foods differently and even reacts to those same foods differently over time or in different situations. The only real way to find out is personal experimentation and observation.