Losing weight and nutrition?

Celestialsi

I'm a relatively younger athlete, swimming vigorously for 1-2 hours, nine times each week. Eating more than 1,000 calories makes me feel stuffed, but I know that I should be consuming more to maintain my health. I just never feel hungry. My family has always pressured me about eating more and nutrition, and so I've recently become a little chubby, weighing roughly 140 pounds. Standing at 5'10 i don't seem severely overweight, although I still would like to lose 15-20 pounds. I have been consuming roughly 1,200 calories each day, and have been exercising regularly, but can't seem to loose weight. I often find myself satisfied thought the day, but eat around 900 calories at dinner and after. Does anyone know how I can lose weight, but eat enough (and healthy enough) to stay healthy?
(Terribly sorry if this dosent make much sense; I'm terrible at putting thoughts into words!)