Effect of behavioural modification for small portions size consumption on BMI in college students of North India: a quasi experimental study

Abstract Introduction Large meal portions contribute to the rise in Body Mass Index (BMI) leading to higher burden of Non-Communicable Diseases (NCDs), especially among the youths. College students frequently exhibit poor dietary habits; thus, it is important to pay attention to their eating habits in order to lower their risk for NCD. Therefore, we conducted this study with objective to measure the effect of health promotion intervention for small portion size consumption behaviour on body mass index (BMI) among college students in Chandigarh, India. Methods We conducted this quasi-experimental research among college students aged 18–21 years from two colleges with co-education, having same streams considered as intervention and control from 2019 to 2020. Motivating group therapy, individual counselling, classroom training including power point presentations, lectures, and messaging via WhatsApp were implemented to the intervention group. No intervention was applied to the control group. Results Overall, the mean BMI decreased in the both the intervention (n = 149) and control groups (n = 142) between the baseline and 6 months post intervention follow up period. The difference in difference (DID) of mean using paired t-test analysis showed that the estimated difference between the two groups was statistically significant for BMI (0.21; 95% CI 0.117–0.244; p-value < 0.001) and for waist hip ratio (0.02; 95% CI 0.001–0.005; p-value 007). There was reduction of 8.1% (from 28.9 to 20.8%) in obese, while 2.7% (from 44.3 to 47.0%) increase in participants with normal BMI in intervention. On the contrary there was almost no change in the proportion of obese and overweight participants in control group after 6 months. Conclusion Considering the higher surge of obesity especially among the Indian youths, this study provided significant contribution in the field of public health in view of effective health promotion intervention to reduce BMI levels, by which get hold of the rising trend of this alarming problem. We recommend pragmatic community level large scale randomised control trials with frequent and controlled follow up to generate further evidence.