I get why it’s confusing, if you have insulin resistance, are prediabetic, and looking for a way to make your numbers better. I had a client today who was exasperated. She reads the low carb ‘experts’, and they say to eat plenty of good fats and hardly any carbs (sugar is the devil incarnate) and definitely avoid fruit (except for a small serving of berries). You read other ‘experts’ and they talk about low-fat, plant-based being the way to go. And plenty of variations on these themes, such as the Mediterranean Diet. 

Everyone is looking at one piece of the puzzle, one possible approach, one part of the science, and then investing their career and marketing the hell out of it. So be careful when you go with someone who has an investment, has written a book, and built their career around a particular approach. They immediately have a bias. It may have worked for them. At least when they wrote the book. But is it right for you?