Adolescents become aware of their own body and how their peers view them around age 12. During adolescence, girls start to develop larger breasts and wider hips, while boys gain weight as they start to grow taller, according to the KidsHealth website. Weight loss occurs when you burn more calories daily than you consume. Those who are overweight as pre-teens may have weight problems — and the health concerns that accompany them — as adults. Instead of focusing on weight loss, make modifications to your family's lifestyle that help your 12-year-old find a healthy weight and body image.
Reduce your 12-year-old's caloric intake. This will both stop weight gain and lead to weight loss. With a doctor's help, figure out the number of calories your child need based on his age, gender and activity level, and reduce daily caloric intake accordingly. According to the Centers for Disease Control and Prevention, reducing your daily caloric intake by 500 to 1,000 calories will result in 1 to 2 pounds of weight loss a week. Start by eliminating high-calorie junk foods and sugary beverages.
Switch to healthier snacks and meals. Instead of cookies or chips when your child gets home from school, provide chopped vegetables or a piece of fruit. Fill your family's plates with whole grains, fresh fruits and vegetables, low- or non-fat dairy products and lean protein. Reduce high-calorie condiments such as ranch dressing or ketchup.
Pack your child's school lunch rather than having her buy it in the cafeteria. A healthy sandwich on whole-grain bread, low-fat yogurt and a piece of fruit is much healthier than the average school food offerings, which can be high in fat, calories and sodium.
Encourage your 12-year-old to drink more water. One soda contains 150 calories or more, while water has 0. Flavor water with lemon or cucumber if they find it difficult to drink. Aim for at least 8 cups of water a day.
Get your family on an exercise program, the CDC advises. Find your child's favorite activity and try to keep it up for at least 30 minutes. Work up to 60 minutes of physical activity most days of the week. Walk, jog, swim, ride your bikes or play soccer. Aim for at a moderate exercise level, meaning that you should be able to talk while working out for most of your workout. Try to include 30-second bouts of vigorous activity, where you are all moving as fast as you can, in your workout. Work out as a family or ask your child to bring along a friend to help her stay motivated.
Make sure your 12-year-old gets plenty of sleep. According to research published in 2010 in the "Australian and New Zealand Journal of Public Healthy," obese adolescents between the ages of 9 and 18 go to bed later and get less sleep than children of normal weight. Pre-teens and teens still need between 8 and 9.5 hours of sleep each night. Make sure your 12-year-old heads to bed at a decent hour to ensure he is getting enough sleep.
Consult your child's doctor before he begins any new diet or exercise program, and for any specific suggestions the doctor might have for your 12-year-old.