Effect of breakfast omission and consumption on energy intake and physical activity in adolescent girls: a randomised controlled trial

It is not known if breakfast consumption is an effective intervention for altering daily energy balance in adolescents when compared with breakfast omission. This study examined the acute effect of breakfast consumption and omission on free-living energy intake (EI) and physical activity (PA) in adolescent girls. Using an acute randomised cross-over design, forty girls (age 13.3 (SD 0.8) years, BMI 21.5 (SD 5.0) kg/m(2)) completed two, 3-d conditions in a randomised, counter-balanced order: no breakfast (NB) and standardised (approximately 1962 kJ) breakfast (SB). Dietary intakes were assessed using food diaries combined with digital photographic records and PA was measured via accelerometry throughout each condition. Statistical analyses were completed using repeated-measures ANOVA. Post-breakfast EI was 483 (SD 1309) kJ/d higher in NB v. SB (P = 0.025), but total daily EI was 1479 (SD 11311) kJ/d higher in SB v. NB (P < 0.0005). Daily carbohydrate, fibre and protein intakes were higher in SB v. NB (P < 0.0005), whereas daily fat intake was not different (P = 0.405). Effect sizes met the minimum important difference of >= 0.20 for all significant effects. Breakfast manipulation did not affect post-breakfast macronutrient intakes (P >= 0.451) or time spent sedentary or in PA (P >= 0.657). In this sample of adolescent girls, breakfast omission increased post-breakfast free-living EI, but total daily EI was greater when a SB was consumed. We found no evidence that breakfast consumption induces compensatory changes in PA. Further experimental research is required to determine the effects of extended periods of breakfast manipulation in young people.