Childhood obesity is caused by small changes in energy balance
19 May 2016
Small changes in a child’s daily energy balance (intake versus consumption of calories) determine whether that child does or does not become overweight in the long term. This is evidenced by Saskia van den Berg’s doctoral research conducted at the National Institute for Public Health and the Environment (RIVM) in conjunction with the University Medical Center (UMC) Utrecht Julius Center.
Van den Berg used data of 2,190 children taken from the PIAMA study, a large-scale health study among children. Ten percent of the children who participated in the PIAMA study became obese between the ages of two and three. On average, these children gained 4.8 kilograms more than other children with a normal weight at the end of the study. Van den Berg calculated that for 90% of the children who are overweight at the age of 6, this extra weight increase in four years’ time corresponds with a calorie surplus of 75 kcal or less per day. To exemplify: 75 kcal corresponds with one glass of soft drink or 30 minutes’ walking.
Obesity is still one of the greatest health problems. In 2015, 12% of youngsters (from 4 to 20 years old) were overweight. Overweight is caused by a disrupted energy balance, where the calorie intake is greater than the calorie consumption. Based on her research, the researcher at the RIVM believes that it should be possible to prevent obesity among this group by making small changes to their diet and exercise behavior, for instance by drinking water instead of soft drinks, or by cycling or walking more often instead of being driven by car. On the other hand, this research shows that a calorie surplus is quickly built up. Eating a small bag of chips or a chocolate bar is already enough. Van den Berg says it is important that people are aware that such choices in diet and exercise behavior do make a difference.
Obesity due to genetic variations
Genetic differences between people can have an effect on calorie intake, calorie consumption and fat storage and ultimately obesity. In her research, Van den Berg discovered links between body mass index (BMI) and girth and five variations in genes that play a part in fatty acid and glucose metabolism. For instance, a certain genetic variant occurs in the SIRT1 gene of approximately 17% of all Dutch people. Adults with this variant had a higher BMI (0.5 kg/m2) than those who did not have the variant. Incidentally, Van den Berg says that not all people with a genetic sensitivity to obesity do indeed become obese. “It might be easier for them to become obese, but at the end of the day they can avoid obesity by means of a healthy diet and enough exercise.”
The results described above are taken from two monographs of the thesis entitled “Diet and overweight. Epidemiological studies on intake, environment and genetics” by Saskia van den Berg. In this thesis, the RIVM researcher describes research into a wide range of dietary factors and obesity, among which fish consumption during pregnancy, energy density of food and changes in food provided at secondary schools. Van den Berg believes that providing healthier food is important for getting people to eat healthy in appropriate amounts.