Someone please put me out of my misery!

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Hi all,

I am having a big problem with my exercise calories.

Basically, I have been very strict with my calories and exercising for the past 9 days. The first week I weighed in, I lost 2.4kgs (5.29lbs). I know that was pretty amazing, but I since then I have been putting on 100 grams (3.52oz) every day.

I have been calorie counting for many years and have never experienced this before. I am logging and weighing everything religiously (even those little snacks and nibbles!).

It was suggested to me that it could be because I am building muscle, but I doubt it happens that fast.

Another suggestion was that I am not eating enough. To clarify, I eat between 1200-1300 calories a day - I do not usually eat my exercise calories earned.

Can someone tell me what I am doing wrong? More importantly what is the advice on exercise calories? I know we are meant to be eating half, but I am always scared that the exercise calories on MFP are a little on the ambitious side and therefore do not really want to eat the exercise calories just in case.