I've been hanging out w/ some people, affiliated with "Beachbody" (P90X, Shakeology, I'm not selling it. Aside from the $$ aspect of it--Shakeology isn't cheap-- it seems to offer a usefully supportive community similar for that sort of thing, except there, the answer to many questions is "Shakeology" instead of "pump/ CGM" LOL...) who work out a lot with both general health and weight loss involved, although some of them are into lifting and getting more muscle, which is a separate challenge.
After 5 weeks, I've noticed that when I don't eat 1800 calories/ day for a day or two, I'll stop losing weight so I think that's the minimum number of calories. The people who are really into it and have gotten excellent results pay attention to macros, or macronutrients, adjusting the %age of carb/ protein/ fat depending on what their goal is. To lose weight, it seems to be useful to aim for 30/50/20 and to get more muscle more like 40/40/20, not a huge difference but it's pretty easy to track with online apps and I'd have to say it's healthier than watching TV and eating potato chips or whatever. I've dropped about 10 lbs in 5 weeks so far, but am not totally hitting the diet on weekends and drinking on top of it, although working it into my macros. There's a lot of stuff to look up about these things online without spending money and I think that it offers a better solution to losing weight. +/- 10% may not seem like a huge difference but when I have 50% protein and manage to do it without flip-flopping the fat and carb %ages, I will usually drop a couple of pounds quickly. And then drink three beers to celebrate and get back to where I started. Oh well.
I'd peaked about 275 lbs c. 204 and am now about 190 lbs. A big thing for me was to look closely at what I'm eating and try harder to eat things that are better for me. I still slip up but the "doses" of stuff like potato chips, cookies, or even juice for hypos, can really throw off calculations if you spend a bit of time and use an app (these are free. I like the Lose It! interface better than myfitnesspal but they work in similar ways, you put in the food and it keeps track of what you're eating). If you keep an eye on things and shop around for stuff e.g. 10G of carbs to treat a hypo, say a glass of skim milk, which will also include protein, instead of a 20G juice box (total quess, I've never been a juice box fan...), you can shave some carbs, avoid rebound highs and see if it can help you meet a weight loss goal. I did all kinds of stuff, swapping veggies in and chips and crackers out, going for plain yogurt instead of fruity, etc. It can turn it into a bit of a video game and even though I'm not massively successful, I can see improvement when I keep an eye on it.