P52 Analysis of Energy Intake at Breakfast and Physical Activity in College Students Yields the Ideal Breakfast Size

Abstract

<h3>Background</h3> Skipping breakfast in young adults is a growing nutritional problem in Japan that results in lower energy expenditure in the morning. <h3>Objective</h3> We examined the relationship between energy intake at breakfast and physical activity to determine the ideal breakfast size (in kcal). <h3>Study Design, Settings, Participants</h3> A cross-sectional study of twenty healthy undergraduate student volunteers (5 males and 15 females) recruited from Shukutoku University, Japan. <h3>Measurable Outcome/Analysis</h3> We assessed dietary intake over the course of 7 consecutive days using the dietary recall method. We calculated energy/nutrition intake using standard tables of food composition in Japan. After excluding days of self-reported unusual dietary consumption, the remaining 133 days were analyzed. Intensity of physical activity and step counts were measured with a Polar V800 accelerometer. When recorded activity was 2.0 METs (standing intensity) or higher, it was regarded as "active time." A breakfast-skipping day was defined as no-energy intake before 10:00 am. Data were analyzed with unpaired <i>t</i> tests and regression analyses. <h3>Results</h3> Active time and step count were significantly lower on days when breakfast was skipped (n = 38/133) than when it was not (active time: 187.6 vs 267.1 min/day, <i>P</i> < 0.005; step count: 6,283 vs 9,458 steps/day, <i>P</i> < 0.005). Linear regression showed a significant positive correlation between energy intake at breakfast and active time. An inverted U-shaped quadratic curve was a better fit than a straight line. The resulting regression formula indicated that an energy intake of 526 kcal would yield the longest active time. <h3>Conclusion</h3> Our study suggests that too little breakfast, as well as too much breakfast, can lead college students to be less physically active. Knowing the ideal morning energy intake and the effects of skipping breakfast can help design more effective nutrition education and maybe reduce breakfast-skipping habits in young adults.