Can i have an advice on how to lose 20kg?!

there is a simple answer for your problem youre just like me all you need to do is:
1) for breakfast eat anything you want after that eat nothing untill its lunch time.
2) for lunch eat a low nice and healthy meal afterwards eat nothing
3) eat a green apple befor 7:00 pm and after 7 eat nothing.

eating a green apple at night makes you loose 1/2 kg a day. its true it worked on me and my brother. (p.s. i also heard it in a medical report) i am now very thin because of that diet THAT SIMPLE DIET.

Well losing 20 kg as fast as possible. is very unlikely, you need exercise, but because of your study I suggest to you that you change your diet a bit, that should keep lowering your weight slowly, also if you are on a healthy diet already, try your best to give your self some time for exercise and play sports, even if its just about 10 minutes, run up and down a set of stairs for a few minutes. or just go for a jog around your area, exercise is the best way of loosing weight. try those suggestions above and you will lose weight quickly. good luck and remember, exercise is the cure of obesity, and trust me, I was in the same situation like you before.

1.You should eat somthing which without calorie,for exaple,cheese,suger,chocolate,ice cream.
In your daily diet and driver, you should eat more vegetable and rough food(corn,soybean,flour),don't drive coco cola and seven up and so on,just take some tea,chinese green tea can lose some oil in your intestine,and also can let cheer up and have more energy when you are studying.(instead of coffee）。Do you know why most of chhinese is very slim,just because of that.

2. Reduce your food,i mean you should eat what is just enough for you,don't eat so so full.

Jesus christ that's like 16 stone.

You need a religiously strict diet. No more donuts for you fatty.