actually the "heap" of pounds you add on from one or two individual meals/events is generally just water retention. if i remember correctly what my dietician told me: 1 gram of carbs holds 10 grams of water...
i might be off on the exact figure - but it´s definitely similar to this.
munch a pizza and the next day you´re bound to be a couple of pound heavier - you can probably also feel it in your fingers as they become slightly swollen with the water - in my case i can generally tell within half a day even and hands & feet become quite painful (if i keep the carb-intake up - i can add knees, ellbows, and generally all joints to that - there is a reason why i´m supposed to cut most of the carbs out of my diet).
carbs are not just bread, pasta, etc. they´re in all sugars & all alcohol.
it´s important to remember that most of us react differently to different items - so try out - keep a diary - make a note of what feels good (not just while you´re eating/drinkin it - but also a day or more likely two days later) - and act accordingly.
i´m fine with potatoes - should stay totally away from wheat - rye i ok - corn so so... chocolate - better not - most fruit great - pasta (even wheat pasta) ok if al-dente - absolute no-no if well cooked...
the best way to find out what works is to start with a few basics - eat only those - if they are fine, add individual items one at a time and wait a day or two to see how your body reacts - then add other items - also individually.
i have also found that starting the meal with protein helps - i.e. the first 2 - 3 bites should be protein - eat slowly - the body then realizes there is something good coming that it can use and starts processing it so when the other stuff is added, it also gets processed (used). if you start with carbs - the system says - oh yeah sugars - and immediately produces insulin which causes the body to store the food instead of turning it into ready energy.
another important factor is: wait 5 hours between meals - i.e. full meal of protein - some carbs - veg followed by fresh fruit (sugars always last so the processing is in full working order when they enter the system) - these should be within half an hour to 45 minutes - then absolutely no food (or juice or othe sugars) for 5 hours - so that the body has time to really use up what it has received and hopefully also some of the stuff stored in the fat cells. the moment you add some food or sugars between meals, the body again produces insulin which starts the storage process again (turning calories into fat deposits instead of energy). the time between food during the night (your rest period), should be 8 to 10 hours - the longer this is the more stored energy is being used.
a bit long winded - and probably not all correct the way i explained - but this is what i got out of the stuff my dietician and my physician have tought me - and itßs helped me loose quite a bit of weight in the first part of this year - i´ve had to hold that weight steady and am ready for the next step to loose. according to my dietician, if you go to much too quickly it´s just taking on momentum to make it up the hill again... work at loosing weight for 3 months or so - then amend your eating habits so you stay steady at this weight - when you donßt really have to work too hard at keeping it steady, you´re ready for the next loosing session. when you want to go downstairs, you don´t jump to the next landing (or out the window), but take one step at a time.
the idea is to change our eating habits so that they become our way of life - if we think we´re having to forego stuff all the time - we´ll never be able to stick to it - or will probably become unbearable grumps.
every ounce helps - as lorchen said - the idea is not to become a stick insect - but to become healthier and get more energy to do the things that are important for us. and if you had an great meal - fell off the wagon so to speak - don´t waste time worrying about it - but enjoy the good time you had and check yourself a bit more during the next couple of days.
and on that note - good night - time to sleep off some of those reserves