As an ex-fitness instructor/personal trainer the rule of thumb is to lose apx 2-2.5pounds a week max. if you are looking at losing a stone in a week you will need to be prepared for saggy skin and perhaps rippling skin as your body will start to eat it’s own muscle. the best way is to reduce your calorie intake by 500 calories a day and to burn off 500 calories a day which will result in 7000 calorie reduction in a week which is equivelant to 2 lbs. of fat as 1 pound of fat = 3500 calories. Losing 1 stone in a week those numbers that you need to reduce by will be 49000 calories a week (or 7000 a day)……… not realistic. As far as the food goes just remember ….quality in = quality out. There is no quick fix for weight loss it is a lifestyle that you need to adapt to. Sorry if i have gone on a bit but it is the truth and before educating myself about what is correct I tried all of the quick fix diets (and failed) and now it is simply about healthy eating and regular exercise.