How soon do you gain weight and collect fat after you eat a bunch of junk food?

You could eat junk food and still lose weight. If your burning up more calories then your eating then you will lose weight. If your eating more calories then your bodys burning then you will gain weight. The 1 problem with eating all junk food is that junk food is high in calories so you cant eat too much of it. If you had a healthy diet you could eat more food keeping you full for longer. What i do is eat a normal healthy diet on the weekday and on weekends i eat whatever i want. If i want a pizza i have it and just work it into my caloric intake for the day. Its usually 10 calories per pound to maintain your weight. Thats just a rough estimate. If your a REALLY active person then you would need a bit more calories. But look over the last few months and have you gained weight? Lost weight? Or maintained your weight? If you have just maintained your weight cut back on 300 calories and then burn 200 calories with exercise. Maybe a 30 minute jog or a fast pace walk for 1 hour. Making a 500 calorie deficit everyday at the end of the week you will lose 1 pound. Weight loss and weight gain is a slow process. You need toeat 3500 calories on top of your normal calorie intake for the day to gain 1 pound. Say your 180 pounds and you need 1800 calories to maintain your weight. You would have to eat 5300 calories to gain 1 pound in 1 day. Thats alot of eating . Normal weight gain is not like this.