I agree with this.
Not eating UPF's is NOT a diet. Swapping sourdough for regular sliced bread and cooking meals from scratch will is not a 'plan' weight loss.
Fat loss can ONLY come from calories in being lower than calories out.
That said, I'm just over 40lb down since the switch, and it kind of IS about the switch, but also not at the same time.
If your UPF habits are particularly bad, then cutting them can cause weight loss. When you cut out snacking on biscuits, crisps, chocolate etc every afternoon, for whatever reason, you're cutting calories.
Also, by avoiding UPFs, you remove some of the cravings for it over time. One of the most pernicious elements of UPFs is the millions companies spend trying to find the perfect mixture of chemicals that will excite your mouth and brain so much that you will want THAT product again and again in the future. They are trying to make life long customers by making their product the only one that 'hits the spot' for you.
It's incredibly freeing to both know this and to feel these cravings reduce over time.
Yes, as I said earlier, some days I just want Monster Munch or a Pot Noodle, but 99 of the time I can look at the craving and recognise that I want those things because I'm tired or sad or stressed and I've attached the way they've made me 'feel better' (with CHEMICALS) to my emotions, AND most of the time, when I do have them, they are in no way as nice as I remember them.