I disagree with the “everything in moderation” idea. If I made a mantra it would be “rinse it until you get sick”.
I have been following Matt’s advice for about 9 months to great success. First off I upped my calories in easy ways, like drinking milk instead of water, having an extra meal. In general I was eating healthy foods and not junky foods, but with no taboo on any food, except quinoa. I packed on a lot of weight eating home made cheesecake and really saw my temperature rise. I’ve just survived a Welsh winter mostly with thin socks, sometimes no socks! This is a real achievement.
After the cheesecake phase I paid more attention to salt and fluids, then systematically eliminated almost all PUFAs, whereas I had been relaxed about these at first. Coconuts do not grow in Wales, not even on this continent, so switching to coconut oil has been a bit pricey and difficult to find a stockist, but that was when everything changed. Now I never want crisps/ chips, even when in front of me, I do not crave chinese food, often the thought of it turns my stomach, I can hardly even do fish and chips, except in one place where I’m pretty sure they are using palm oil (which I used to avoid on ethical grounds but it, esp. palm kernel oil is also a fairly high sat fat oil). Biscuits, sweets and cakes are another one, unless I know they’re all butter I just won’t eat them, I don’t even need to try, I have just become highly adverse to PUFA containing foods. If I do end up eating them to any great extent, though, I do feel physically wronged.
The point being, make gradual incremental changes and trust your appetite, even if it tells you to gorge. If my experience is owt to go by, you can basically eat exactly what you fancy until one day you won’t fancy any “bad” foods and your health will be good.