Well I would still allow yourself to grow a bit. When I was 14 (28 now) I was probably around the same height maybe a little shorter and only a few pounds heavier. As time went on I eventually started putting on weight. Also I have another friend that no matter how much he eats he has never gotten past 120, so I guess it would sometimes depend on genetics too. But if you wanted to eat healthier I would follow what Firefreak posted but increase the quantity a bit so that your body can develop correctly.