recently a few weeks ago, i noticed i was gaining a littel weight after staying at 48 kilos for years. i have been keeping a strict diet of fresh salads, cooked vegetables, small amount of sweets, etc. (i'm sure i'm not exceeding 1000 calories a day) and exercising almost every day at the gym (spinning, aerobics, dance, etc.). instead of losing weight i've put on 2 kilos! can't figure out why this is happening!
Additionally, you might want to have your thyroid tested; one of the major symptoms of hypothyroidism (under active thyroid) is weight gain. Insulin resistance will also cause weight gain.