I've lost 50lbs now by managing portion size and limiting treats and junk food, etc. Drastic dieting only works in the short term. I've been losing weight for almost 2 years now, and even with the holidays and travel, I didn't gain back the weight because I had made lifestyle changes slowly, over time that became my new habits. Fad diets are called fads for a reason. There may be some good things to pull from them but anything that has you doing a 180 instantaneously on your eating and exercise habits will not be sustainable and, therefore, not be long term. Consider adding one new habit a week or month (and once that habit is second nature, then add another). For example, limiting portion size by measuring each meal, could be one new habit. Or limiting processed foods or the number of times you eat out. In the end, weight loss is really calories in versus calories out. All the systems like WW or keto or whatever are created to simplify that in some way with some angle, like WW lets you eat all the fruit and veggies you want (for the most part), and keto limits carbs, etc. The systems are trying to take the thinking out of it. But again, drastic changes done overnight rarely stick. Better to take your time and go slow and have a lifetime of results versus a few months or weeks or even just days at a goal weight, then gain it all back.

Just my thoughts on the matter. I lost weight by monitoring portion sizes and counting calories using my Fitbit app. There are lots of apps out there that you can use for free to count calories.