Abstract
PurposeWe previously observed increased energy intake (EI) at the meal before planned afternoon exercise, but the proximity of the meal to exercise might have reduced the scale of the pre-exercise anticipatory eating. Therefore, this study examined EI in the 24 h before fasted morning exercise.MethodsFourteen males, experienced with gym-based aerobic exercise (age 25 ± 5 years, BMI 23.8 ± 2.5 kg/m2), completed counterbalanced exercise (EX) and resting (REST) trials. On day 1, subjects were told the following morning’s activity (EX/REST), before eating ad-libitum laboratory-based breakfast and lunch meals and a home-based afternoon/evening food pack. The following morning, subjects completed 30-min cycling and 30-min running (EX; 3274 ± 278 kJ) or 60-min supine rest (REST; 311 ± 34 kJ) fasted. Appetite was measured periodically, and EI quantified.ResultsAfternoon/evening EI (EX 7371 ± 2176 kJ; REST 6437 ± 2070 kJ; P = 0.017) and total 24-h EI (EX 14,055 ± 3672 kJ; REST 12,718 ± 3379 kJ; P = 0.011) were greater during EX, with no difference between trials at breakfast (P = 0.761) or lunch (P = 0.071). Relative EI (EI minus energy expended through EX/REST) was lower in EX (EX 10,781 ± 3539 kJ; REST 12,407 ± 3385 kJ; P = 0.004).ConclusionThis study suggests planned fasted aerobic exercise increases EI during the preceding afternoon/evening, precipitating a ~ 10% increase in EI in the preceding 24-h. However, this increase did not fully compensate for energy expended during exercise; meaning exercise induced an acute negative energy balance.
Highlights
As the prevalence of overweight and obesity continues to rise globally, effective strategies to facilitate successful weight control are needed [1]
Total 24-h energy intake on day 1 was ~ 1340 kJ (~ 10%) greater in EX compared to REST (t = 2.966; df = 13; P = 0.011) (Table 2; Fig. 2)
This study investigated the effect of an anticipated morning-fasted aerobic exercise session on appetite and energy intake in the 24 h before exercise, compared to an identical resting control trial
Summary
As the prevalence of overweight and obesity continues to rise globally, effective strategies to facilitate successful weight control are needed [1]. Results from these studies have shown that there is considerable interindividual variability and the expected reductions in weight (calculated from exercise energy expenditure) are often not induced Several mechanisms, such as compensatory increases in hunger/energy intake [20] and decreases in non-exercise physical activity [21] have been proposed to explain this response. 60 years ago, Jean Mayer suggested the concept that exercise induces compensatory increases in energy intake to restore energy balance [23] This concept, intuitive, is not consistent with short-term energy intake measurements made at meals consumed post-exercise, where exercise seems not to affect energy intake [9, 24]. It was hypothesised that energy intake over the afternoon/evening meal, and perhaps lunch (given the results from our previous work), but not breakfast, would be greater before exercise compared to rest
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