Textbooks & meta-analysis industry journals are the really the only options that can guarantee a removal of all personal bias. Given the nature of nutrition as a whole, it will not tell you what to/not to eat, but rather inform you about what effects different foods have on the body generally. From there, you can make your own informed decisions as to how you want to structure your diet
The Teaching Company has a few well constructed courses on science based nutrition and diet under the great courses label. I have a subscription to Audible.com, and obtained them as audio books. Though you could access them through the Teaching company if you prefer a visual presentation. Both courses came with supporting pdf files detailing the references, and providing a full transcript. They are university quality material, presented in an easily accessible manner.
Tldr: if you are born in a first world industrialized country, you are already on an “extreme diet”
Never before in history would you be eating gallons of vegetable oil per year, canola in everything, every sauce condiment, mayonaise, all made out of soybean oil in the first ingredient. Sugar added to everything from beans to ketchup. Less than half the recommended amount of daily fiber. All high glycemic foods.
For science-based nutrition advice, I suggest “The end of overeating” by David A. Kessler, MD, a former Surgeon General of the U.S. I also suggest “Eat, Drink, and Be Healthy” by Walter C. Willett, MD, from the Department of Nutrition at Harvard’s School of Public Health. If those aren’t enough, consider “Good Calories, Bad Calories” by Gary Taubes, a renowned science journalist who’s won three Science in Society Journalism awards from the National Association of Science Writers. Happy Healthy Eating!
Lol. Nothing is “extreme” when it is contradicting modern living styles of eating.
The state we live in where 90% of our food comes from 5 plants and a handful of animals from a handful of companies is already “extreme”
So cutting this out and trying to live more naturally by avoiding it is not “extreme”.
It isn’t always beneficial to take an ultra-centrist take on everything.
That’s like walking into a den in a bad neighborhood and seeing people shooting heroin, smoking meth, and smoking crack 24/7 and saying “Hmm well i dont want to be extreme, i wont leave completely, I’ll just smoke a little bit of crack”.
It doesn’t make you modest or intellectual or sophisticated.
“Everything in moderation” is good advice, but you are already raised in a modern first world country where the starting point, the typical, is already freakishly unhealthy and giving people record rates of chronic diet-related illness.
I’m not telling you to go on some stupid carnivore diet or be like Liver King, but don’t write off diets because they aren’t “moderate” enough. Literally does not make sense.