Eat more food... Seriously though, when people try to lose weight they have a tendacy to cut back on their food intake thinking that less food will make then burn fat faster. In reality, cutting back on your food intake can cause your body to become catabolic and makes it less likely to burn excess calories if you are training hard. The best thing you can do is eat a tonne of fruit (banannas, kiwis, oranges, apples, mangos ect.), a lot of high protien low fat meat (chicken breast, lean beef, tuna), lots of whole wheat bread, cottage cheese, and egg whites. When I was trying to get in shape i mad ethe mistake of cutting back on food intake and after a month and a half i lost 5 pounds and put on no strength. When i upped my food intake i lost 25 pounds in three months along with raising my bench press 45 pounds. this wasnt doing martial arts though; this was training in a gym and running.