I am currently working on losing fat only, I do cardio 5 times a week and weight training, and I always eat less calories than my maintance. Sometimes however I go over my calorie count by like 500 (say my parents want to take me out to eat if they come to town). Let's say i've done a full weight training workout for that day. For that one day will I gain muscle? According to all the theories on this site, I should gain a miniscule amount of muscle just for that day because I have excess calories and I have worked my muscles. What do you guys think?

It takes ~3500 kcals to gain a lb of muscle of lose a lb of fat. If you knew exactly how many kcals you needed above maintenence for your specific activity levels for the day and how many kcals you needed below maintenence then it is possible to gain muscle and lose fat. Essentially you'd have a pretty insane roller coaster ride of kcal fluctuations from day to day. The body typically doesn't like to roller coaster as such so that you're hitting pretty extreme opposites.

So, if you hit 500 extra kcals and all you had no excessive macronutrients at one sitting, then it is possible that you might have gained 1/7th of a lb of muscle.

But nothing ever comes out as cleanly in real life as it does on paper.

what is the time span that your body needs these extra calories to convert them into muscle? I always figure it's daily, or 24 hours but I don't think anybody can really tell right? Like if I would work out today at 5 pm full body workout, and have a loss for the day of 500 calories, but woke up the next day and starting eating a lot and by the time supper is here I have already ate 500 extra calories, am I suppose to gain muscle then?

nobody knows?

the day you have 500 extra cals will probobly build a bit of muscle, but its almost nothing.

the body works on trends, not a single day of extra calories.

any 'extra' muscle that could be put on with the extra 500 cals is so insignificant you'll never notice it.

It really does depend on the individual person, some people need more calories to put on muscle some need less as well ofcourse the exercise breakdown.

Check out this article:

The energy components of food | IdealBody4Life

Key word there is theories, that's why i highlighted it. It's very possible to gain muscle and lose fat at the same time but in saying that, it's also hard. You need to know what you're doing for it to work. To answer your question, no eating one huge meal a week after a work out won't help you pack on the pounds.

what you eat every day is important,but also getting good nutrition around training times is also very important.
you need energy before you train to help train harder,also when you pick up a weight you start protein synthesis, this is where the muscle breaksdown and rebuilds (basicly put) so if you have protein allready in your system it can help repair quicker,so pre and post meals are very important.

the past 10 days I was back at home on a vacation. I lifted and did a full body workout 3 days a week and ate on average 4000 calories per day, give 2000, or take 1000 (my maintance calories is around 2,100). After the ten days were over I ended up gaining about 7 pounds. How much of this do you think is fat, and how much of this is probably muscle?

All fat,,,,,,,,,,

most fat, no need to eat that much over maintence. just because you force feed the body doesnt mean it can force make muscle. The body will reach its limit in how fast it can make muscle, and it will store what you eat as fat instead.

Yes, I agree. Most of that is fat. You should really count your calories and dont over eat!

I would also like to add that you should not think of a calorie as just a calorie...if that makes sense??

well yes i'm not completely an idiot I knew that most of it was fat, I was just looking for a number of how much of each. I'm guessing about .25 pds muscle and 6.75 pounds of fat. I was at 9.3 percent body fat before this and it's really easy for me to lose and gain weight whenever I want to, so i'll have this extra weight off in about 3-6 weeks. I kind of did this as a test too just to see what would happen if I ate whatever I wanted whenever I wanted.

What did you mean by not each calorie being a calorie though?

Also when I decide I want to bulk up this summer how many calories should I go for per day? (I knew that this many calories was just going to end up as fat as i said)