Permanent gain? Probably not possible. Temporary, with your system packed with food (with a bit being permanent), most likely. I've gone up ten pounds in two and a half days of deliberate eating, but only a couple of pounds stuck around by a few days later.
What I did was just plan modest sized meals every 2-3 hours all day, with a bit of extra snacking, and then fill up on as much high calorie junk as I could fit in shortly before bed. So like get up, have a bowl of cereal (maybe with high fat milk), surf the net a bit, have a shower and get ready for the day. Head out and pick up a high calorie coffee and half a dozen donuts and those. Go buy some groceries, eat a few cookies on the way home. Put away the groceries. Change into looser clothes. Have first lunch (say a sandwich, fruit, yoghurt, some veggies, glass of milk and a few more cookies). Play on the computer for a couple of hours. Have second lunch, perhaps some instant ramen with tuna and grated cheese, and since you are surprised to still find some room a peanut butter sandwich and some more cookies. Go for a walk and get an iced coffee while out, show off your bulging belly. Get home and collapse into a comfy chair for a bit and play on your phone until you realize it is time to eat, decide to head out and grab a fast food meal. Get home feeling pretty full so stretch out on the couch with something to read, doze off after a while, wake up and it is almost 7pm so you make a proper supper, maybe a beef and broccoli stir fry with rice, and you eat a load of it including as much rice as you can manage. Feeling pretty unpleasantly bloated by now you stretch out for a bit, then go for a short waddle, then have a hot shower. All of that seems to have settled you down some, so you open up the cheesecake that you'd bought in the morning and left out on the counter, grab a fork, and see how much you can get down, and manage three quarters of the 1600 calorie thing, then guzzle down as much fruit juice as you can still fit into your gut, until you feel like another bite and you will spew and you can barely breath. Stream something for a bit until you are mobile enough to go to bed, then realize how hard it is to get comfortable when this bloated and regret your decisions for a while, but finally go to sleep.
Then wake up in the morning, eager to do it all over again. Find you can't fit in quite as much, as your system is still partially full from the day before, so focus on getting in the most calorie dense foods at each meal, and on not letting lack of appetite stop you from eating steadily all day. Finish up with another stuffing. By this point you go to bed with your gut feeling enormous because it is really stretched bloated out with all the food still inside you.
you won't get a better answer than the previous one... possible yes, permanent not likely, there are pros and cons of a rapid weight gain, personally i would prefer my lady to gain even just 10 pounds per year, but to keep them , and let it roll
I'm a grazer rather than a glutter. Yes I just made up the word glutter lol. I munch throughout the day. For example i'll make a big bowl of curry and rice and eat it all day long. Or just bowls of cereal. Whatever's handy.
I put on about sixty pounds, but it's taken me almost twenty damn years. This could be due to early conditions of privation and want (I was homeless for a while) combined with a fast metabolism. I'm from desert rat stock and we tend to burn fat to stay cool, I guess. But now that i'm hitting near the forty mark things are slowing down.
Time to heat up the taco filling now.