Some of the most solid and evidence-based advice (as opposed to fads) is coming from the Newcastle University research team. Their focus is on controlling Type-2 diabetes. However, they have discoverd that the best way of controlling it is to reduce weight - and remarkably, have shown that in most/many cases, weight reduction results in Type 2 Diabetes being eliminated. Which has been quite a surprising result.
They have developed extensive advice on how to initially reduce the weight (essentially, an 800-calorie per day diet of three shakes and a low calorie meal of salad and protein) and then how to keep it off. All of this is applicable even if you don’t have Diabetes. I cannot claim long term success (yet) but it is certainly effective for weight loss in my case.
If you’re interested in a science based approach - that has significant peer-reviewed results, it would be worthwhile having a look at their website. I’ve included a couple of links below.
https://www.ncl.ac.uk/magres/research/diabetes/reversal/#publicinformation