Welcome to the forum! The metabolism is complex. As you review the threads on this forum, you'll likely see the term N=1 many times. We use that to indicate that consumption of the macros (fat, protein, carbs) is not the same for everyone. Each individual has a unique insulin resistance (IR) quotient based on how the individual has eaten over the past many years and how his or her metabolism has responded to those eating habits. Some of us do very well with extremely low carb approaches for the long term. Being very low carb has helped me eliminate IR. Others can tolerate different ratios and do just as well. It's never one size fits all. Part of this journey is finding the right combination of foods (macros and types) that enable you to have success with whatever your goals are.

You're reading a very well thought out book by two experts who have had much success in promoting a ketogenic approach. Yes, saturated fat is emphasized (and it's healthy despite what we've been told since the late 70s), but your ratios are critical and protein consumption tends to be one of the more misunderstood factors in this case. To go into ketosis, one must strictly limit carbs and protein. If you consume too much protein at the expense of carbs, your metabolism will use that protein to produce glucose. There is a "sweet spot" (no pun) for each individual. Loading up on healthy fat is not always the answer. Fat does help with satiety, but too much undermines the process as well. Find your correct ratio of macros and follow the recommendation of protein levels using the lean body mass calculation in the book. Remember they're using lean body mass and also remember that an 8 ounce piece of meat does not contain 8 ounces of protein. Rather, depending on the protein, there are approximately 7 grams of protein per ounce of total protein source weight after subtracting for water, fat, tissue, etc. Yes, it's a journey, but a very rewarding one when you start to find the correct levels that enable success for you.