Elsevier

The Journal of Nutrition

Volume 149, Issue 8, August 2019, Pages 1326-1334
The Journal of Nutrition

Skipping Breakfast Before Exercise Creates a More Negative 24-hour Energy Balance: A Randomized Controlled Trial in Healthy Physically Active Young Men

https://doi.org/10.1093/jn/nxz018Get rights and content
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ABSTRACT

Background

At rest, omission of breakfast lowers daily energy intake, but also lowers energy expenditure, attenuating any effect on energy balance. The effect of breakfast omission on energy balance when exercise is prescribed is unclear.

Objectives

The aim of this study was to assess the effect on 24-h energy balance of omitting compared with consuming breakfast prior to exercise.

Methods

Twelve healthy physically active young men (age 23 ± 3 y, body mass index 23.6 ± 2.0 kg/m2) completed 3 trials in a randomized order (separated by >1 week): a breakfast of oats and milk (431 kcal; 65 g carbohydrate, 11 g fat, 19 g protein) followed by rest (BR); breakfast before exercise (BE; 60 min cycling at 50 % peak power output); and overnight fasting before exercise (FE). The 24-h energy intake was calculated based on the food consumed for breakfast, followed by an ad libitum lunch, snacks, and dinner. Indirect calorimetry with heart-rate accelerometry was used to measure substrate utilization and 24-h energy expenditure. A [6,6-2H2]glucose infusion was used to investigate tissue-specific carbohydrate utilization.

Results

The 24-h energy balance was −400 kcal (normalized 95% CI: −230, −571 kcal) for the FE trial; this was significantly lower than both the BR trial (492 kcal; normalized 95% CI: 332, 652 kcal) and the BE trial (7 kcal; normalized 95% CI: −153, 177 kcal; both P < 0.01 compared with FE). Plasma glucose utilization in FE (mainly representing liver glucose utilization) was positively correlated with energy intake compensation at lunch (r = 0.62, P = 0.03), suggesting liver carbohydrate plays a role in postexercise energy-balance regulation.

Conclusions

Neither exercise energy expenditure nor restricted energy intake via breakfast omission were completely compensated for postexercise. In healthy men, pre-exercise breakfast omission creates a more negative daily energy balance and could therefore be a useful strategy to induce a short-term energy deficit. This trial was registered at clinicaltrials.gov as NCT02258399.

Key Words

breakfast
carbohydrate
exercise
energy balance
fasting
metabolism
physical activity
substrate metabolism

Abbreviations

BE
breakfast before exercisee
BR
breakfast followed by reste
FE
overnight fasting before exercisee
FGF-21
fibroblast growth factor 21e
OGTT
oral glucose tolerance test.

Cited by (0)

Funding for this work was provided by the European Society for Clinical Nutrition and Metabolism and the Rank Prize Funds. DT, JTG, and JAB are funded by the MRC (MR/P002927/1) and the BBSRC (BB/R018928/1).