1. Introduction
T2D, cardiometabolic disease, CVD, fullness, tiredness, appetite and mood
CVD, BLOOD, TYPE 2 DIABETES, CARDIOVASCULAR DISEASE
Girls often begin to skip breakfast during adolescence. This study compared the acute effect of breakfast omission versus consumption on cardiometabolic risk markers and perceived appetite and mood during rest and/or exercise in adolescent girls classified as habitual breakfast consumers. Girls (aged 13.2 ± 0.7 years) completed two 5.5 h conditions in a randomised crossover design: breakfast omission (BO) and standardised breakfast consumption (BC). A standardised lunch was provided at 3 h. Incremental cycling exercise was performed at 5 h. Blood and expired gas samples were taken at regular intervals. Whilst pre-lunch plasma glucose, insulin, and Metabolic Load Index incremental area under the curve (IAUC) were significantly lower in BO versus BC, post-lunch differences were reversed and larger in magnitude. Peak plasma glucose and insulin were significantly higher in BO versus BC. Pre-lunch perceived fullness and hunger were significantly lower and higher, respectively, in BO versus BC. Perceived energy and concentration were lower, and tiredness was higher, in BO versus BC. Exercise peak fat oxidation and Fatmax were unaffected. The lower physical activity enjoyment in BO versus BC approached significance. To conclude, acutely omitting breakfast adversely affects cardiometabolic risk markers and exercise enjoyment among adolescent girls who habitually consume breakfast.Prevention is more effective than a cure, and moderating postprandial glycaemia and insulinaemia is integral to cardiometabolic disease prevention, including type 2 diabetes (T2D) and cardiovascular disease (CVD) [In adults, omitting breakfast exaggerates glycaemic and insulinaemic responses to subsequent meals compared to when breakfast is consumed; this has been termed the ‘second-meal effect’ [