well, first off, you can't "spot reduce." you can't do push ups and expect to lose the fat off your arms... if anything, you'll make them look worse because you'll add muscle bulk below the fat, and because you've got the fat, you can't see the tone, and it just looks like more fat.
fat is your body's way to store extra energy. it stores it in certain places, which are determined genetically. I store fat on hips and thighs, my mom stores it around her middle. that's just how it works.
The only way to get rid of stored energy (FAT) is to take in less energy (CALORIES) than you burn. That forces your body to burn its fat stores. And you lose weight. You burn energy by exercising aerobically (hit the bike or stairmaster for at least 30 minutes...it usually takes you five or ten minutes to get your heart rate up to where it needs to be to burn extra calories, and you should work out at least 20 mins beyond that for maximum benefit... push-ups and sit-ups are anaerobic and don't help you burn fat. you'll gain muscle with these exercises, but you won't lose fat.)
Places to look at cutting calories:
stop drinking alcohol. alcohol, especially beer, has lots of extra calories.
cut down on processed carbs, like white bread, tortillas, and crackers.
little things you can do to help move things along quicker:
take the stairs instead of the elevator. I used to work on the 14th floor...14 flights of stairs a few times a day worked wonders.
put an exercise bike in front of the television... I don't watch TV unless I'm on the bike. It makes things go faster because you're distracted by the TV show, so when you're done you're like "oh, its been an hour already?!"
shell out the cash for a personal trainer for a few weeks. believe me, it makes a huge difference. they can tell you your target heart rate, and make sure you're using all the gym machines correctly. five or six sessions should work to start. then stop working with the trainer until you feel you've hit a plateau, then go back to get help adjusting your program.
contrary to what most people think, KARATE IS USUALLY NOT A FAT-BURNING EXERCISE. Although sparring can be an aerobic activity, it's only aerobic if you get your heart rate up and keep it up for an extended period. most sparring matches are three minutes long, and not long enough to get any real cardio benefit from. Most of your punches and kicks are going to be strength building (anaerobic) because you kick, stop, realign yourself with the target, kick again. you never really get your heart rate up.
You should not lose weight quickly, if you're doing it right. The first five pounds or so will come off very fast, and after that, you shouldn't lose more than a pound or two a week. If you lose more than that, chances are all you're losing is water weight and you'll gain it right back. take it slow and you'll keep it off. Weigh yourself at the same time every day, preferably first thing in the morning before you have breakfast. (and you need to have breakfast. it jump starts your metabolism, encouraging your body to burn more calories, because it knows that there are calories available and you're not starving). your weight fluxuates throughout the day, so weighing yourself at the same time every day will let you accurately track your progress... you're usually a pound or two heavier at the end of the day than you are in the morning because you've been eating and drinking all day. If you feel tired, you cut your calories too much and need to eat more. Calories are energy, so don't restrict your food too much, just cut the stuff that you know isn't good for you (beer, sweets, processed breads, fried foods, fatty foods...subsititute a grilled chicken breast on a bun instead of a hamburger, and save yourself a few hundred calories). You shouldn't feel hungry. Adjust the kinds of food you're eating rather than how much you're eating.
if you really want to lose weight, its simple:
cut calories
spend 30 minutes 3 times a week doing aerobic exercise.
It sounds too simple, but it works...I've lost 20 pounds. It took me 4 months to do it, but I've kept it off, and I look and feel great.