If you are just starting out, don't worry about it - focus on low carb and high fat. You want to get into ketosis - and eventually become keto adapted. good article here on keto adaptation: http://www.ketotic.org/2012/05/keto-adaptation-what-it-is-and-how-to.html

So my recommendation is to not worry about it until about your third or fourth week. For most, their appetite starts to decrease by then anyway.

Eventually though, a few hundred calories over every day will matter.

What is your calorie limit? Make sure it is higher than 1200. I put mine at 1500, stay below 25 net carbs a day and don't gain. 1200 is not realistic for me.

I count, and have since day 1 of doing low carb. 2367 is my number, but as long as I'm under 2500 I don't worry. I have been allowing some extra carbs here and there, nothing major. My goal is 50 net, if I go to 100 once in a while I don't worry about it. I have no idea if I'm in ketosis or not, or if it really even matters, since the scale is moving.

I count. 1200 is my number for a little less than 1 pound a week. I end up going over by somewhat 100-200 regularly. It makes for super slow weight loss. I am terrible about getting exercise in. I try to get some exercise in on days I know I'll be going over. I don't sweat over my macros too much as long as I don't knock myself out of ketosis. (hasn't happened yet) I eat more than 20 carbs a day. my fat and protein I find hard to hit with still eating nutrient rich food. But I believe I am eating far over the minimums of either. I am actually less worried about hitting macros than staying exactly 1200 calories.

too much protein kicks you out of ketosis. Fat is fuel, a lot of nutrients are found in carbs but again too many carbs will kick you out. You need your fiber that doesn't count against.

But I've found I can get by with A lot more carbs than 20 or even 35. for the first three weeks I tried to stay at net 35 and then crept up to net 50.. from there I've crept up to about net 60 on average although I've gone over that a few times and been ok.

I count calories while low carbing (netting around 20 carbs a day) , for a really long time 1463 was my magic#, no matter how much exercise i did.... And then i kicked it into high gear with the excercise and i stalled, and even gained. It didnt make sense to me.. So i experimented, i mean why not? I wasnt losing the way i way doing it, so screw it.

After reading a million different things on the internet, some saying i needed more cals, others saying i needed less, i decided to try doing less... That lasted only a few days, i gained instead of losing and just could feel that i wasnt taking in enough for the amount of excercise i do. Some people told me to give it more time, but i knew- i needed more cals. So back to the drawing board i went, i added more cals but was unsure of how many to add. I read so many things that it all just started confusing me, and then i read that i should be NETTING around 1200, not taking in 1200. Holy crap, it was like christmas!! Ive now been eating around 1800 cals a day but netting around 1200 and i'm losing. MFP actually reccomended 1200 but i was afraid to eat back cals so i never went with their reccomendation until recently.

So for anyone watching their cals AND carbs, just add exercise- it buys you more cals when you need them

Just swapped to LCHF at the weekend, although as a runner, I'm not restricting my carbs as much as some of you. I lost my weight over the summer through 5:2, low-carb, low-cal, calorie-counting and exercise so I don't want to lose any more. What I DO want is to not feel hungry all the time now and not to be craving carbs as I really do feel they are the "bad guys" so I have upped to full-fat everything again. I still log everything daily here and my calorie count has gone through the roof. My previous calorie allowance was 1480, which I upped to 1600 when I started maintenance a month ago (increase gradually until you find the balance) but now it is regularly over 2000. And I've lost two pounds this week!!! What the hell is going on??? lol

Glycogen stores reducing, most likely (they hold water, so it shows quite a bit on the scale). It'll settle out in a week or two as your body adjusts.