Which slimming methods are best/most sensible in achieving a permanent weight loss?
The best way to achieve a lasting weight loss is to continually use good eating habits.
More about good eating habits and weight loss.
If by slimming is meant eating much less than what the body needs, then that is a bad method. Slimming can promote the development of eating disorders. However, if a person stops overeating fat, the body will adjust itself to a lower weight. Slimming as a time limited weight loss cure is useless.
If, after slimming, a person reverts to previous eating habits, then the weight will soon increase to what it was before.