Also, someone who weighs over 300 pounds should not be eating so few calories. I know that you are trying to lose weight, but even at 184 pounds, I still eat no less than 1800 plus working out. And I still lose weight (it's when I'm not exercising or watching what I eat that nothing happens). My guess is that you put your body into starvation mode. With the cut in calories and swimming laps plus hiking trails, my estimation is that your body thinks there's a famine (although I should say I am no psychologist... just my guess). If I were you, I'd increase the cals, keep the workout and watch sodium intake. Oh, and add some weights!