The good news is, metabolic damage can be repaired. You just need the right combination to stimulate the metabolism with exercise and nutrition needed to achieve this and not just a diet and this anger will eventually yield positive results.
The great irony is most diet programs that claim to help you get rid of excess weight, only end up making it harder to actually do it long term due to decreased metabolism, diets are not sufficient and not exercising, or almost never do weight training.
It may take a little longer if you have really messed things up with a severe diet to the point limit of the famine in the past, especially if you have lost a lot of lean body mass, but this can be reversed but not can be done immediately, it takes about three weeks to get your metabolism starts working well.
Always remember that you must combine exercise with diet, but does not work, but for this diet effective most important thing is not starving, so eat vegetables, fruits, and put aside all meals full of fat, flour or soft drinks full of sugar and always remember to eat every three hours and most importantly, after training.