Gaining

I suspect you could get on the scale in six weeks and have it show you 23 pounds heavier.....but gaining 23 pounds of fat would be a lot harder. That is, if you are really stuffing yourself, you'll have several more pounds of food in your system, you can easily drink a few extra pounds of water, so you'd maybe need to gain a dozen pounds, which sounds posible if you are really planning on pigging out.

On the other hand, to gain 23 pounds of permanent weight, eh, I don't know. Have people gained that much in that amount of time? Yes, and more. Will your body cooperate? (Tolerate that much food, give you enough appetite to even attempt that much food without someone forcing it down you, leave you feeling well enough not to turn you off the whole thing, and then actually turn enough of the food into fat....) Who knows. Our bodies are a LOT more complicated than eating X additional calories always turns into Y extra pounds.

One additional thought....if you are really serious about it, probably your best bet is to take all the usual diet advice and adapt it to what you are doing. As in: the key is planning, making sure that you'll have lots of food for all of your meals, that you have snacks handy and that you remember to eat them, that your plan and discipline makes sure you eat even when you aren't hungry. Also you can turn some of the usual diet advice on its head: do eat heavily shortly before going to bed, do eat a lot of carbs, etc.

OK, two additional thoughts: trying to change your body in a hurry is almost always going to be rough on it. If you can be patient, probably much less damaging to gain that weight over a number of months by simply eating larger amounts of generally healthy foods. Will avoid insulin highs and lows, stress on your liver, and will give your skin and muscles more time to adapt to the changes in your size and weight.

-Ed