I went down a similar path, sans book. I opted to remove processed foods from my diet in its entirety - to be clear, I consider neither oil, nor vinegar to be processed. This has resulted in basically the only processed food in my life now being soy sauce.

The hard reality is that food, which I already enjoyed, tastes significantly better. Similarly, when I fall off the wagon and have some UPF (crips).. it just tastes flat. Highly recommended, even without the health benefits, frankly.

That's quite hardcore. Well done.

I've noticed the same flatness you're describing with a similar product. The other week I had two items spaced across different meals. I'm still permitting bread as long as it's real or homemade (4 ingredients max, hard after 2/3 days), which was the first, and then later I had "made-in-store" chips with the a bunch of UPF and spices (preserved).

After about 2 weeks of minimising UPF, the bread tasted much better than it usually would, even on its own. Then not only did the chips taste flat like you've experienced, but they didn't taste good, and I felt I could almost tell what they'd added to try and get you to finish them.

I find it quite insidious how much food is falsely branded as healthy ("Just Natural" snack bars) or fresh. Not just items that are dressed up as if they are made fresh in-store, but foods proudly showcasing claims about things added, or nothing bad being added, only to be invalidated by checking the ingredients on the back.

The extra difficulty to eat was a pretty big takeaway for me from that book. Imagining most processed food as having been broken down and reformed, the breaking of the food matrix, the sort of pre-digestion that stops my body doing that instead, the hurrying of the eating process to get more in before the body works out its full, have all been useful for me to slow down my eating and avoid this stuff in general.

I have noticed that my scattergun approach of avoiding stuff that's been transported long distance and overly branded (judged by packaging in both cases), has made supermarket trips very quick and simple. 80% + of the big stores must just be rubbish.

It's led to me doing most of my shopping at local markets, where things are loosely packaged in paper. The book > avoiding branded packaging got me down the road of avoiding plastic wrapped consumables wherever possible, because plastic leeching is also a concern.

The only disadvantage is that my food environment has shrunk a lot, and as an endurance runner it's made it quite hard sometimes to get enough energy in. For that reason I don't think I can drop pasta and bread entirely.