Losing 20 kilograms -- or 44 pounds -- is a major goal, but it won't happen overnight. You can lose this weight safely in about five to five-and-a-half months with dedication and effort. Keep the weight off by making simple lifestyle changes. Maintain these lifestyle changes, and you will keep off the weight for good.
Reduce your caloric intake by between 500 and 1,000 calories per day. According to the Centers for Disease Control and Prevention, this drop in calories will result in losses of between 1 and 2 pounds -- 0.453 and 0.907 kilograms -- per week. Women should not reduce their calorie intake below 1,000 calories a day, while men should stay about 1,200 calories per day, according to the National Institutes of Health.
Eat healthy foods to ensure you meet nutritional requirements while staying within your calorie limit. Emphasize fruits and vegetables as well as whole grains and low-fat milk products. Include lean sources of protein such as poultry, fish, lean cuts of meat, beans and eggs.
Avoid refined carbohydrates which have a high-glycemic index -- foods such as sugar, white flour and white rice, which can cause a spike in your blood sugar levels. A 2012 study by the New Balance Foundation Obesity Prevention Center at Boston Children's Hospital, which was published in the "Journal of the American Medical Association," found that low-carbohydrate or low-glycemic index diets are more effective than low-fat diets when it comes to achieving lasting weight loss.
Increase your level of physical activity. The National Institutes of Health recommends 60 to 90 minutes of moderate physical activity each day to maintain weight loss. Moderate physical activities include water aerobics, playing basketball and social dancing.
Incorporate high-intensity interval training into your workout routine. High-intensity interval training is a form of workout that alternates between high-intensity and low-intensity activities. A study published in the "Journal of Applied Physiology" in 2006 found that participants burned more fat after just two weeks of high-intensity interval training. According to Columbia Health's "Go Ask Alice!" website, high-intensity interval training may condition the mitochondria to burn fat calories before carbohydrate calories.
Make strength training part of your regular workouts. Muscle tissue burns more calories than fat, so building muscle will increase the amount of calories you burn -- helping you to shed pounds. Cutting calories can cause you to burn muscle as well as fat, so it is essential to add strength training to avoid muscle loss if you want to lose weight quickly and efficiently.