Exercise with moderation. Try work out an exercise roster or take up martial arts twice a week, its a great work out and you'll be learning self defence at the same time.
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Proper diet, changing of eating and lifestyle habits, exercising, body detox, proper nutritional supplementation help to lose weight. Avoid unhealthy ways - smoking, starvation, making yourself sick and over exercising.
Proper diet: Use the Food Pyramid and follow that day by day. Fruits are good for weight loss... ;P