Gaining

I have been gaining since I was 18 and 65 kgs
Now I'm 22 and I'm 108 kgs

My weight gain, is mainly from junkfood, I do a big stuffing almost every night before bed at macdonalds.
Arround 6 cheesburgers and half a liter of Coke og more.
All the added fat, and me gaining very fast have offcource left me covered in stretchmarks, and 43kgs of added fat and I'm getting so easily out of breath aswell 😅
But how unhealthy is it to overeat so much on junkfood/fastfood daily and almost 365 days every year?

The main thing is to eat healthy food as well. You can still eat junk food, but ideally have one meal a day where you eat healthy. This will not eliminate health risks but should mitigate them some.