yes HIIT will help, it should be done around 4 times a week. maby you should look at spock's post a little closer. proper nutrition and cardio, also and lowering your calorie intake. here is some good info on cardio
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CARDIO: there are two main types of cardio you should use, first is called slow cardio and the second is called HIIT (high intensity interval training). you should use them in a ratio of 3-1 (IE 3 days of slow and 1 day of HIIT). For best results do cardio 4 times a week for an houre, too much is somtimes counterproductive and too little is well too little. "what is slow cardio?" slow cardio is doing any activity (running, biking, swimming, boxing, etc) with about 75-85% of your max heart rate for an houre. "how do I know what my max heart rate is?" well when you do an activity where you are still able to talk without being extremely out of breath, or another easy way is take 220 and minus your age then take that number and multiply it by .75-.85 which will give you rough percentages of 75-85% of your max heart rate or (HR), of course this is not entirly accurate, cause everyone is different. "ok what is HIIT then?" HIIT works like this first you warm up doing whatever for 5 min then take some time and stretch. after your all ready, start a moderate pace for 1 minute then you move your pace up to 90-95% of you max HR for the next 15-30 seconds, then go back down to your moderate pace for 1 min, then back up to 90-95% and back down agen. you get the idea (moderate for 1 min, then 90-95% for 15-30 sec) do this around 15-20 times and your done.