distractions! watch a movie, youtube videos, etc. to take your mind off of what you're eating ^_^ another tip is if u can't eat a few big meals in one day, u can divide them up to small meals that'll add up (i.e. 3 big meals vs 5-6 small meals). if you don't feel like chewing, buy or make some smoothies/shakes for drinks!
also just a side note to anyone trying to gain weight in general - while fast food might be an easy route to gaining weight, it'll be detrimental to your health because of its ingredients. make sure to eat foods that contain nutrients and will make u feel full such as protein, fats, and whole grain