Strongly recommend you discuss a VLCD diet with a physician before attemping, they should only be done under supervision. I also, personally, have found more success making habit changes and finding eating strategies that will work long term (ie. permanently), rather than charging in with extreme calorie restrictions.
Another danger of that kind of approach is the permanent metabolic changes that can occur, which would leave you burning less calories than another person of the same weight (which sucks, because that also means you'd have to eat less permanently). Bear in mind, the outside extreme of safe fat loss is 1-2lbs/week, which is a calorie restriction of ~3,500kcal/lb of fat. Easiest way IMO to do this is: calculate your BMR with an online calculator, subtract 300kcal from your TDEE and add 200kcal worth of exercise (which is about 30min of running, for example).
Also important is nutritional quality, not just calories: focus on quality proteins (MINIMUM 0.8g/kg body weight, but during fat loss you're better off to aim for 1-2g/kg bodyweight), lots of veg&fruit, and whole starches/grains. Try to avoid refined carbohydrates (eg. anything white really: sugar, flour, white bread, etc) just because they tend to spike insulin which can lead to you being hungrier again faster (booo). The most satiating foods are protein and high fiber foods; eg. lean meats & broccoli, cottage cheese & salad, etc.
Best of luck, stay safe, have fun!
Keto or vlcd
