Lately I have been toying with the idea of doing a 4-6 week diet. People have suggested to me before that I should do a short "cut," because after a few weeks, my body would be more susceptible to weight gain (I have no idea if this is true or not). i am thinking about doing Lyle Mcdonald's Rapid Fat Loss diet.
Heres my story: I have been eating in excess of 4500 cals per day for several years now, sometimes going much higher than that. I eat as much as i can, often force feeding, and i also eat calorie dense foods. I am 20, my bodyfat hasn't changed in over 4 years, and right now i am sitting at 180lbs at just under 5'9''. I know that i simply need to eat more to get bigger, but my lack of progress is discouraging at times, and because I swim, play lacrosse, play badminton (for those who have never played it it is very intense), go to the gym, and play football, I feel like my body is just exceptionally efficient in using up calories. Anyway, enough of that crap.
I have tried to slow my metabolism down with little success. You're talking up to 7000 cals/day - honestly! I have to take much of it in liquid form. I tried dieting more frequently (for several weeks actually), but this doesn't make a difference - your body simply gets back up to speed again...so by the time protein synthesis etc is ticking over for gains again after some weeks, your metabolism is "humming again". Not only that, but many people underestimate the amount that is burned from activity (not just resting metabolic rate), and that's high for some people.
There is one thing you can do though, and me and brother has had some success with it. Basically, you reduce workload slightly. If you train 6 days per week, reduce it to 4 days per week (workouts have to become very focussed/based more on compounds). If you do 3 sets/exercise, do 1 or 2 (as long as warmups are done, and keep warmups to lower reps).
This should "save you" up to ~1000 cals/week
Other than that, just add more liquid calories.
Most people who're heavily bulking usually hold their weight for some time (to solidify gains and/or to lose a little fat). They do this by eating slightly less than maintenance or at maintenance. It takes time but it works
To gain muscle, you can only either decrease output (activity etc), or increase input (food).
Don't listen to all those program's that promise something magical to happen in a matter of days/weeks ("diet for 1 week, and bulk for 2 weeks to get lean gains and spurt muscle growth!!!")...gaining muscle is a long term thing (where you are in a positive energy balance) and something that needs to build up momentum over time.