Weight loss intentions of adolescent females in New Zealand

Abstract

Background: Adolescents, in particular females, have been recognised as a high risk group in terms of trying to lose weight. Little is known about the prevalence of New Zealand female adolescent weight-loss intentions and how this differs in relation to weight status and energy intake.

Objective: To investigate the weight-loss intentions of adolescent girls in New Zealand by (a) estimating the prevalence of females currently trying to lose weight in a sample of girls attending eight high schools across New Zealand; (b) identifying whether weight-loss intentions differ by weight status; and (c) describing energy intake differences between adolescent females trying to lose weight compared to those who are not.

Design: Female adolescents between the ages of 15-18 years were recruited for the first wave of the SuNDiAL (Survey of Nutrition, Dietary Assessment, and Lifestyles) project in March – April 2019. This is an observational, cross sectional, study run through New Zealand high schools. The prevalence of females currently trying to lose weight was assessed via a questionnaire. Weight and height were measured by trained researchers and weight status determined using the WHO growth charts. The energy intake of adolescents was assessed with two 24 hour diet recalls administered by trained researchers on separate days of the week.

Results: One hundred and forty-five female adolescents took part in the study, 46% were currently trying to lose weight, while 29% and 23% were doing nothing to alter their weight or trying to stay the same, respectively. Of those participants who were trying to lose weight, 46% had a healthy weight, 37% were overweight and 17% were obese. Those trying to lose weight were consuming on average 810kJ (95% CI: 159kJ to 1461kJ) less than those not trying to lose weight, and were 1.0 BMI z-scores greater (95% CI: 0.6 to 1.4).

Conclusion: The prevalence of adolescent females trying to currently lose weight was 46% in this sample, with nearly half of these girls having a healthy body weight. However, girls who were trying to lose weight were, on average, heavier than those not trying to lose weight but were consuming significantly less energy per day.