in the army i alternated running 4 miles at a 7 minute-per-mile pace, with swimming a mile's worth of laps [33] at the base pool. it kept me hellafit and on my 6'3" frame i never exceeded 170. only when i got out of the military did the weight creep back on due to not continuing said regimen. so i'm living proof that swimming a mile's worth of laps [in 30 minutes or so, which is 2 miles per hour] will [with proper diet] shed the fat and keep it off, especially if you vary your swim strokes, like doing crawl for a while and then backstroke for a while like i did. swimming like that was the only time in my life that i could describe myself as having a sleek physique. anyways, the speed and duration are key to keeping your body in the aerobic fat-burning zone long enough to lose weight. up the odds of fat loss by biking back and forth from the pool. and avoid any food that is white [refined and starchy].
as far as swimming "like a girl," there were plenty of women at the pool who could swim laps around me with one hand and one leg restrained. i have never been better than a very graceless swimmer with an ugly movement in the water. but i kept at it and burned the calories anyway. chances are the OP can swim more attractively than i ever could. anyways, when too many pounds piled up on my buns and my pants wouldn't fit on 'em anymore, i went back to swimming and the weight dropped back down after 6 months of that. the advantages of swimming are-
*being in the water keeps one cool so there is no obviously unpleasant sweating
*the water supports one's weight, so the joints are protected from the burden of weight
*the water is relaxing and soothing as it flows past one's body
*if one's shoulders get sore or gets tired of swimming, one can just walk back and forth in the lanes, the water resisting the movement of the body through the lane is very good exercise as well.
i miss living near a pool.