Hello actually it is really easy to lose weight while eating a lot of Fast Food. what you have to do is run and that’s actually the key. Let me tell you from my personal experience. What my problem was: I can’t stop eating and eating a lot! Meanwhile I also didn’t want to gain the weight. I wanted to keep eating a lot of food specially fast food but didn’t want to gain weight.
What I did was that I made a special schedule. I just stopped eating anything 2 hours before I go for running. So whether I was in office or in a fast food shop or at any other place, when I planned to run, I just stop eating food 2 hours before. For example, if I planned to run at10 o’clock, I just stopped eating at 8 o’clock. Within that time the whole food in your stomach gets digested and help you to give a joyous feeling while running!
Now the real game starts! Whether you are tired sleepy or whatever … you have to Run!! Run!Run!Run! at 10 o clock
And you have to run for at least half an hour. Just run the way you can weather fast, slow, jumping, running backwards but you have to keep running. This half an hour will change your life. You can eat whatever you want, you can enjoy whatever food you want in your life. But you have to follow this routine.
Actually it’s a start of an healthy life. You will be enjoying a your life style. Your muscles will feel a lot more relaxed and you will start feeling energetic even in your daily routine. It will also give you a motivation to run more and make your muscles look better. It is actually start of an ideal life 
My friend just start this and you will really start enjoying your life style
.