Some kids are naturally lean but for others being underweight is a sign of an underlying condition. Generally speaking it's very reassuring if a child is otherwise healthy, has a good diet, is tracking along a growth curve and has a similar physique to other family members.
Children are considered underweight when their body mass index (BMI) is below the 5th percentile for their age and gender on growth charts, according to the CDC study. If a child is underweight, the pediatrician may ask more about medical history or could order testing to check for undiscovered health issues, Dr.
Many guys and girls are skinny until they start to go through puberty. The changes that come with puberty include weight gain and, in guys, broader shoulders and increased muscle mass.
According to the CDC, most 13-year-old girls weigh between 76 and 148 pounds (lb). The 50th percentile for weight in this group is around 101 lb. This means that about 50% of girls this age weigh less than 101 lb. If a 13-year-old girl weighs under the fifth percentile, a doctor may classify this as being underweight.
“It's normal for a child to slim down between ages 2 and 5,” says pediatrician Roy Kim, MD. “Your child will look their thinnest about the time they start kindergarten.” It's hard to eyeball a healthy weight, though.
More significant weight gain is normal during the preadolescent ages of roughly 9 to 12 and adolescence – as a child matures into a young adult. It's not unusual for the body to store fat during this time as it prepares for the rapid growth and changes associated with puberty.
Puberty – Increased hormones in a child's body during puberty (between the ages of 10 and 14 for girls and between the ages of 12 and 16 for boys) leads to growth and possible expansion of “baby fat” areas. This typically takes place in girls' belly, breast area and hips. Boys' shoulders will get broader.
A high metabolism means a person burns more calories at rest and during activity. Therefore, there is no piling up of fats or weight gain. A very high metabolism rate can be unhealthy as the person is unable to maintain a healthy weight.
It may be that you have a fast metabolism (meaning your body burns energy from food at a fast rate than the people around you) or you're just naturally slender. For some people, underlying health conditions and certain medications and treatments can make it difficult to reach and/or maintain a healthy weight.
According to the CDC, the average weight of a 12-year-old female is 92 pounds (lb) , or around 42 kilograms (kg).
So according to a bmi chart your suggested weight range is 112 - 151Lbs. But many factors such as bone mass, muscle mass and fat percentage are important too. If you are a lot over or under this weight range, consider changing your diet and/or exercise. You are still young so don't push it.
If you are underweight, a healthy amount of weight to gain is usually ½ to 1kg per week, until you reach your target healthy weight. For people who are losing weight unintentionally and are in the healthy, overweight or obese BMI categories, a good goal would be to aim for weight maintenance.
“Thinness is a heritable trait”
So thin people not only stay slim “by not having the obesity genes, but they also have different genes that protect them” from gaining weight, she said. The research concludes that “thinness, like obesity, is a heritable trait.”
Some may be born naturally small and their low BMI is due to their genes. Some may have a very high metabolism and find it hard to put on weight, even if they eat foods that have a lot of calories. Some people may not follow a healthy, balanced diet because they forget to eat or they cannot afford nutritious foods.
Each child is born with a genetic blueprint for their predetermined size and shape. Some babies are supposed to be chunky. Some babies are supposed to be skinny. Along with this blueprint, they have the innate ability to eat the right amount of food to support their body type.
A fast metabolism is not the only reason behind it. The answer to this question is quite complex as several factors are at play. Genetics, nutrition, and even behavioural factors are involved which help slim people to maintain their body weight.
under 18.5kg/m2 – you are considered underweight and possibly malnourished. 18.5 to 24.9kg/m2 – you are within a healthy weight range for young and middle-aged adults. 25.0 to 29.9kg/m2 – you are considered overweight.
A high metabolism.
If a person has a high metabolism, they may not gain much weight even when eating high-energy foods.
Even though a 13 year old who is 70 kg is considered to be overweight as they suggest you should be weighing more like 50 to 60 plus kg, you are a growing teenager (providing that you are still growing, I'm only saying this because when I was your age I stopped growing unfortunately for me).
Add the mother's height to the father's height in either inches or centimeters. Add 5 inches (13 centimeters) for boys or subtract 5 inches (13 centimeters) for girls.
For most children, belly fat will be transitional. That is, it will go away as your child grows taller. Making sure your child is getting enough sleep, is physically active each and every day, and eats a nutritious, balanced diet will go a long way to supporting this natural transition into puberty.
Lifestyle issues — too little activity and too many calories from food and drinks — are the main contributors to childhood obesity. But genetic and hormonal factors might play a role as well.