Don't eat junk, you'll feel shitty. Instead i suggest you eat healthy foods that are high in calories like peanut butter or almond butter with apples. Or cooking with olive oil/coconut oil. Also eat lots of nuts like almonds, walnuts, etc. Good luck!
For me I just quit being active and ate food all the time and I started gaining a lot of weight and I'm a 17 year old girl and I weighed about 246 Ibs I was pretty shocked when I weighed myself again and now I'm 315 Ibs.
