Experimental manipulation of breakfast in normal and overweight/obese participants is associated with changes to nutrient and energy intake consumption patterns.

The effect of breakfast and breakfast omission on daily food intake in normal and overweight participants was investigated. 37 participants were recruited for this experimental study and assigned to one of four groups on the basis of their body mass index (BMI) (normal weight BMI <25 kg/m(2) or overweight/obese BMI >25 kg/m(2)) and breakfast habits (breakfast eater or breakfast omitter). All participants were requested to eat breakfast for an entire week, and then following a washout period, omit breakfast for an entire week, or vice versa. Seven-day food diaries reporting what was consumed and the timing of consumption were completed for each breakfast condition. Overall more energy was consumed during the breakfast than the no breakfast week. The present study revealed significant effects of timing on energy intakes; more energy was consumed during the afternoon in the no breakfast week compared to the breakfast week. Overweight participants consumed greater amounts of energy than normal weight participants in the early evening. Breakfast omitters consumed more than did breakfast eaters later in the evening. All groups consumed significantly less energy, carbohydrate and fibre in the no breakfast week; however, overweight participants increased their sugar intakes. Consumption of the micronutrients iron and folate was reduced in the no breakfast week. The findings highlight that the timing of food intake and habitual breakfast eating behaviour are important factors when investigating why breakfast consumption may be associated with BMI.