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Facts and advice about BMI and obesity in children. Written by pediatricians, for parents. A child’s body changes a lot in their lifetime. Babies should put on a lot of fat during their first year of life. During their toddler years, the fat eventually needs to disappear, which it does in most children. Going into adolescence, children put on more fat and muscle again. This is perfectly normal. In this blog, we will go through how to know if your child is normal or overweight, and what you can do to help your child.
Fat babies are normal
Babies are often quite fat when they are born. During the first half of the year they should become even fatter. 6 month old babies often have fat rolls everywhere on the whole body, except over the skull. This is good! Weight gain plays a pivotal role in influencing not only height and length, but also the growth and development of head circumference. Pediatricians worry more about the babies who do not gain enough weight.
Breastfeeding
To follow the growth of babies, we use growth curves. The growth curves used in most Swedish medical centers today were developed based on approximately 3,000 children born in Gothenburg in 1974. During the 1970s, both breastfeeding and formula feeding were common in Sweden. The curves therefore show how a large group of children who are both breastfed and bottle-fed grow. Fully-breastfed babies often grow faster in the first 3-4 months than these curves, and then grow more slowly for a few months. It is usually called a period of accelerated growth. Bottle-fed babies may also have a period of accelerated growth. If you are not aware of this, you might think that the child first grows too quickly and then the slower growth from 3-5 months of age may seem unhealthy.
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Since children under one year cannot be considered “too fat”, you should, in principle, not deny them food based on their growth curve. If, on the other hand, your child’s growth accelerates along the curve, and at the same time seems dissatisfied, vomits after a meal, or has copious stools and stomach pain, they may feel better from a little less food.
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Overweight toddlers
After a child’s first birthday, they should slowly become thinned. This is the time when your sweet little baby becomes a small toddler who can or is learning to walk. The extra movement helps them shed the weight. Additionally, a one-year-old often consumes significantly much less breast milk or formula than before. Some children have no desire at all to eat anything else. That’s when the breast milk or formula is very important and gives the child good nutrition for growth and development. Some one-year-olds completely stop breastfeeding or drinking formula. That is perfectly OK, as long as they eat enough food so their growth continues to follow the curve.
During the second year of life, a child often has a big belly, and round cheeks, but the fat on their legs begin to disappear.
A four-year-old should have a flat stomach
The weightloss takes time, but four-year-olds should not have a big stomach. Towards the age of 5-6, children’s ribs begin to be visible. Therefore a child starting school is normally really slim. This weight change seems to be important for the child to continue to grow reasonably fast.
The BMI curve determines if a child is overweight
How do you know if a child is overweight? Calculate their BMI. The same formula for adults, apply for children. BMI = weight / height*height. But be aware that normal BMI varies with a child’s age. We plot the child’s BMI on a standard growth chart. Then after several measurements, a normal curve is drawn. It is best to follow this curve. This is unlike the length and weight curves where it does not matter which curve the child follows. Then there are curves for overweight and obese children.
Download BMI curves for children here
Ask the health professionals at the children’s medical center to look at the BMI curve to know if your child is normal weight, underweight or overweight.
Obesity in school children
In Sweden, school children are fed until satisfied and weighed by the school nurse. The school nurse is responsible for monitoring the children’s normal weight. If the child is not of normal weight, the school nurse talks to the parents and can also suggest treatment.
Treatment for overweight children
If you have discovered that your child is overweight, it’s recommended you act as early as possible. Unlike adults who need to lose weight, overweight children only need to gain weight more slowly. As the child grows in height or length, they will become slimmer. It is a slow process and should be so.
Small changes, that are sustainable, are the best solutions. Start with one or two changes. Evaluate after a few months. Should you continue or introduce more changes. Until about high school, your child’s eating habits and physical activity are entirely your, the parents’, responsibility.
More movement, eat less energy-rich foods
All lifestyle changes for obese children are based on two things: more exercise, eat less energy-rich foods.
If you are two parents, go through the child’s eating habits with the child’s other parent. Be honest. Does the child eat breakfast? If so, what? Snack? Lunch? Snack? Dinner? Evening snack? Does the child eat at night? Does the child drink fluids other than water? If so, how often? How often does the child eat sweet buns? Candy? Chips? Soft drinks? Juice?
2. Compare the child’s habits with good eating habits for preschoolers . A quick reminder. A preschooler should eat breakfast, snacks, lunch, snacks, dinner, possibly an evening snack. One third of the food should be fruit / vegetables, one third protein and one third carbohydrates. Some healthy fats (nuts, many types of oils). The child needs to get calcium through a couple of cheese slices or a couple of glasses of milk a day. Otherwise do not drink anything other than water.
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Sweets, buns and soft drinks can be allowed once a week (Saturday sweets) in small quantities.
Choosing what to do first
If you have found one or more things about the child’s eating habits that are not beneficial, choose a change to make first . Choose a change that you think will have a big effect and that you think you and your child can implement. My order of priority is usually as follows:
Select one change at a time. Talk to the child’s other parent and make a plan for the change to work. Preparing dinner every day is a huge change in a family’s life especially if you haven’t done it before. Let it take its time. When it doesn’t feel like a burden and becomes the new normal, then it’s time for the next change.
- If your child does not have a good breakfast every day, start with that. Ensure that they have a good breakfast at home or at preschool.
- If your child does not have a good dinner every day, start with that. And maybe make healthy lunches on holidays or every day if they don’t get lunch at preschool.
- If your child does not have a good snack every afternoon, then start with that.
- Stop drinking soda / juice / cordial besides one glass on Saturday.
- Reduce candy consumption to one small bag on Saturday
- Stop eating cakes / buns except once a weekend (cakes or sweets)
- Reduce ice cream intake to once for dessert on the weekend
- Stop the evening meals (after dinner, that is) or replace it with carrot / cucumber / apple
Should I discuss my child’s weight with them?
I do not think you need to talk to preschoolers about their weight, even if they are overweight. But you can talk about what the body needs. Talk about how important it is that the body receives food to nourish it. And explain what the food is. Explain that the adults in the family have decided that everyone in the family should get food that is good for the body, and then explain what changes you will start with.
Overweight school children are often aware that they’re overweight. If this is the case, you can talk about it gently and compassionately. It is important to help children see that there is nothing wrong with them, and nothing wrong with their body. Highlight the importance of collaborative efforts to strengthen the body, making it easier for the child to run and move easily. Unfortunately, it is common for overweight children to be teased. If this is the case, you should absolutely talk to the child’s teacher.
Move more
Make sure that your child has the opportunity to move every day. Think about your daily routines. Maybe your child can walk a bit to or from preschool. Can one parent go out and play running games with the children while the other parent prepares dinner? Or can you imagine encouraging non-touching floor play around the coffee table? Put up climbing wall bars and rings or home ladder in the children’s room? Give the child a kickbike or trampoline for the summer?
Care for overweight children
If you need more help with your child’s obesity, talk to the children’s medical centre or school health care about how to get in touch with a team to treat children with obseity. Doctors, nurses, dieticians and physiotherapists are usually available to help families stay motivated and implement change strategies.
‘An Important Book about Obesity in Children’ is a very good book written by an experienced nurse from Sweden’s largest team for overweight children, Rikscentrum barnobesitas at Astrid Lindgren’s children’s hospital, Sofia Trygg Lycke. It is highly recommended if you need more help.

Boktips: en viktig bok om övervikt av Sofia Trygg Lycke
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