Did I lose fat or muscle?

It's been a long time since I've lifted weights regularly. Since I started my new job, I had been too busy and too tired to go to the gym (the one near my place gets too crowded and smelly after 5pm). I did jog periodically but only at medium intensity.

It was only in the past month, after a change of the office space and change of staff, did I manage to get time after work and energy left to go to the gym and have energy during the weekends to exercise.

But don't worry, the lack of recent photos on my blog isn't because I'd gained weight. In fact, I'd lost weight! The only accessible food at my (new) office is from Starbucks and Coffee Bean. I find paying $7 for a sandwich unthinkable! And I don't fancy eating their cakes or muffins. There's no microwave oven in the office - it is forbidden because some idiot caused a small explosion at another site in the past. If there's anyone to blame for my weight-loss, it would be that idiot.

In particular, my deltoids and biceps look alot smaller. As much as I would like to think that I lost muscle mass due to the lack of my usual strenuous exercise, I think I may have lost fat mostly:
- After several weeks of weight training, I can lift heavier than what I used to lift 10 months ago (or maybe I didn't train very hard previously).
- After 1 time of running my usual hilly route MacRitchie reservoir, I completed it roughly the same timing (46 mins) as I could 2 years ago (average 44 mins, best time 42 mins).

If I had lost that much muscle, I don't think it would be possible to train back the same ability in such a short period.

I read somewhere that once you've trained your muscles to a certain strength, if you stop training for a long time and try to train back to the same standard, you'd be able to train back relatively quickly (compared to the first time). It seems to be true for me.