How to stop losing weight when you have reached your 'goal' ?

Idk, but you are quite tall. Am 150 cm and a guy. )

Go to KFC, McDonald's, Burger King and Dairy Queen all in the same day

Make sure you're eating enough, plenty of healthy carbs (pastas, rice, other grains) for example. Don't actively seek junk food out, because you want to put on healthy weight, not junk stuff.

Yeah, eat more. If you're running long distance you'll never get fat. Believe me, I've been into long distance running a long time now and when I go up 5-10lbs (which is hardly a visual difference other than my abs) I just run more and it's gone within 1-2 weeks.

I eat everything I come across and then just use exercise to balance the difference. You'll rarely gain even 0.5lbs in fat a day (you'd have to eat 4000+ calories to do that), so by that note you'll never gain more than 3lbs in a week even while indulging to your fullest. So eat more, and don't worry about it. Maintaining weight is easy.

It's probably just the habit (of strict dieting) that's hard to break. Habits are always hard to break.
Go to an official medical website or a diet and fitness website to learn which foods would interfere with your training and performance.

I went from 119 to 103 (I'm 5'4) in a matter of 4 months. I never intended to lose weight, just wanted to tone up, but my caloric intake couldn't keep up with my cardio. I've gained 2 lbs back only by forcing extra food (I have no appetite and my stomach doesn't want it), eating a couple of days a week at McDonald's, and I've been drinking a protein shake with a meal. Unfortunately, I did have to cut back on the cardio, but, I've added weight training. I've not lost any more weight. Good luck.