Welcome to Just answer !
I can understand your frustration regarding weight gain and I empathize with you as it is a tough task to loose the extra weight, however it is attainable provided you do that extra bit in your regime which is lacking.
Well one cannot really predict about the time one shall take to loose 11 kg since the amount of weight loss depends upon various factors such as person's metabolic rate, regularity and right pattern of exercises and type of exercises, right diet.
So I am mentioning below some important strategies which you shall employ to loose the extra gained weight.
1) Diet-- You need to get your metabolism going by taking frequent small feeds at 2-3 hour intervals comprising of high fibre diet such as salad and pulpy fruits , cereals but no or extremely low amount of fats and carbohydrates. Also keep your self well hydrated by taking lemonade and coconut water which are good for keeping hydration and minerals intact. Other than this you may continue to take fish 2 times a week but no chocolate as it has got too much of calories..
It will be better if you can maintain a dietary chart .and stick to it judiciously.
2) Exercises -- Cardio exercises such as brisk walking for at least 30 -45 minutes is required along with some yoga exercises on a daily basis except 1 day can be used / week for relaxation.
3) Avoid stress ( regarding weight and other issues ) because it leads to dysfunctioning of body's metabolism thereby leading to weight gain.
Kindly do this much continuously and I am positive that within next 3-6 months you will regain your previous weight and figure, I am afraid there are no short cuts to be taken here and this will be the most natural way to loose the extra kilos gained.
I hope this helps.
Wish you all the best and please do not give up.
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If there is any further assistance needed please feel free to ask using the reply button.
Thank you very much for your time and expert information.
I gained quite a lot, especially the fact that I will loose the weight by making those small adjustments as you have recommended.
Thanks for the kind words. May I request you to kindly leave a Positive rating if you are satisfied with my service so as to acknowledge the same . Warm regards.