"We studied for the first time the long-term effects of a combined physical activity and dietary intervention on insulin resistance and fasting blood sugar in a general population of predominantly normal-weight children", says Timo A. Lakka the lead author from the Institute of Biomedicine, School of Medicine, The University of Eastern Finland, Kuopio Campus, Finland.

The study is published in the Diabetologia journal.

The prevalence of type 2 diabetes and prediabetes has dramatically increased in many countries among children and adolescents. This alarming trend is likely due to decreased physical activity, increased sedentary time, unhealthy diet and consequently increased body fat content.

Several physical activity and dietary interventions, particularly in combinations and mainly short-term, have been shown to decrease insulin resistance among overweight and obese children. "To our knowledge, only one long-term dietary intervention has been found to attenuate the increase in insulin resistance and only one short-term physical activity intervention has been observed to prevent the increase in fasting blood sugar in general populations of predominantly normal-weight children", the researchers highlighted.

"We therefore carried out a 2 year controlled trial to investigate the long-term effects of a combined physical activity and dietary intervention on fasting serum insulin, fasting plasma glucose, and HOMA-IR in a general population of children, most of whom had a normal body weight", they said.

A population sample of 504 children aged 6–9 years at baseline was allocated to a combined physical activity and dietary intervention group (306 children at baseline, 261 children at 2-year follow-up) and a control group (198 children, 177 children) without blinding. The fasting insulin and blood sugar, calculated HOMA-IR assessed physical activity and sedentary time by combined heart rate and body movement monitoring, assessed dietary factors by a 4 day food record, measured body fat percentage (BF%) and lean body mass by dual-energy x-ray absorptiometry were all measured.

The measures of physical activity, sedentary time, diet, and body composition at baseline and 2-year follow-up were analyzed and observations were laid down.

The findings of the study were-

1. Compared with the control group, fasting insulin increased, and HOMA-IR increased over 2 years in the combined physical activity and dietary intervention group.
2. The intervention effects on fasting and HOMA-IR were statistically significant after adjustment for sex, age at baseline, and pubertal status at baseline and 2-year follow-up.
3. The intervention had no effect on fasting glucose, BF%, or lean body mass.
4. Changes in total physical activity energy expenditure, light physical activity, moderate-to-vigorous physical activity, total sedentary time, the reported consumption of high-fat vegetable oil-based spreads but not a change in BF% or lean body mass partly explained the intervention effects on fasting insulin and HOMA-IR.

As a result, the authors summarized that "The combined physical activity and dietary intervention attenuated the increase in insulin resistance over 2 years in a general population of predominantly normal-weight children. This beneficial effect was partly mediated by changes in physical activity, sedentary time and diet but not changes in body composition."

For further reference log on to:

Lakka, T.A., Lintu, N., Väistö, J. et al. A 2 year physical activity and dietary intervention attenuates the increase in insulin resistance in a general population of children: the PANIC study. Diabetologia 63, 2270–2281 (2020). https://doi.org/10.1007/s00125-020-05250-0