How does that work? Surely weight loss is a case of calorie deficit?
The OP is 6 stone overweight, which means that she probably needs roughly 3000 calories a day to MAINTAIN her weight. If she eats below that, she will lose weight, however, if she eats too little, her body will react as if it's starving, create cortisol and try and retain fat. For a person with a normal BMI, the starvation effect occurs at less then 800 calories a day, so for her weight, it might start at 1500.
Obviously as one "brilliant
" poster pointed out, there are no fat people in concentration camps (there are lots of fat people in prison FYI) that's because the body can't continue to store at starvation levels indefinitely, and you will eventually start losing weight, as well as developing a host of other problems associated with starving yourself. So not a recommended option.
The ideal way to lose weight is to initially eat less calories. So, for the OP with her current weight and doing exercise, that may mean 1700, 1800 or even 2000 calories a day. As her weight drops, she needs to readjust, so when she's 3 stone overweight, she may only need 1400 calories, or 1200. And so on.
If you look at WW or MyFitnessPal, they do use this sliding scale.