Biological and behavioral predictors of relative energy intake after acute exercise.

Energy intake in the post-exercise state is highly variable and compensatory eating - i.e., (over-) compensation of the expended energy via increased post-exercise energy intake - occurs in some individuals but not others. We aimed to identify predictors of post-exercise energy intake and compensation. In a randomized crossover design, 57 healthy participants (21.7 [SD = 2.5] years; 23.7 [SD = 2.3] kg/m2, 75% White, 54% female) completed two laboratory-based test-meals following (1) 45-min exercise and (2) 45-min rest (control). We assessed associations between biological (sex, body composition, appetite hormones) and behavioral (habitual exercise via prospective exercise log, eating behavior traits) characteristics at baseline and total energy intake, relative energy intake (intake - exercise expenditure), and the difference between post-exercise and post-rest intake. We found a differential impact of biological and behavioral characteristics on total post-exercise energy intake in men and women. In men, only fasting (baseline) concentrations of appetite-regulating hormones (peptide YY [PYY, ß = 0.88, P < 0.001] and adiponectin [ß = 0.66, P = 0.005] predicted total post-exercise energy intake, while in women, only habitual exercise (ß = -0.44, P = 0.017) predicted total post-exercise energy intake. Predictors of relative intake were almost identical to those of total intake. The difference in energy intake between exercise and rest was associated with VO2peak (ß = -0.45, P = 0.020), fasting PYY (ß = 0.53, P = 0.036), and fasting adiponectin (ß = 0.57, P = 0.021) in men but not women (all P > 0.51). Our results show that biological and behavioral characteristics differentially affect total and relative post-exercise energy intake in men and women. This may help identify individuals who are more likely to compensate for the energy expended in exercise. Targeted countermeasures to prevent compensatory energy intake after exercise should take the demonstrated sex differences into account.

Exercise Shifts Hypothetical Food Choices toward Greater Amounts and More Immediate Consumption.

Although exercise modulates appetite regulation and food intake, it remains poorly understood how exercise impacts decision-making about food. The purpose of the present study was to assess the impact of an acute exercise bout on hypothetical choices related to the amount and timing of food intake. Forty-one healthy participants (22.0 ± 2.6 years; 23.7 ± 2.5 kg/m2, 56% female) completed 45 min of aerobic exercise and a resting control condition in randomized order. Food amount preferences and intertemporal food preferences (preference for immediate vs. delayed consumption) were assessed using electronic questionnaires with visual food cues. Compared to rest, exercise resulted in a greater increase in the food amount selected, both immediately post-exercise (+25.8 ± 11.0 vs. +7.8 ± 11.0 kcal/item, p = 0.02) and 30 min post-exercise (+47.3 ± 12.4 vs. +21.3 ± 12.4 kcal/item, p = 0.005). Exercise further resulted in a greater increase in the preference for immediate consumption immediately post-exercise (+0.23 ± 0.10 vs. +0.06 ± 0.10; p = 0.03) and 30 min post-exercise (+0.30 ± 0.12 vs. +0.08 ± 0.12; p = 0.01). Our findings demonstrate that a single bout of aerobic exercise shifts hypothetical food choices toward greater amounts and more immediate consumption, highlighting the importance of the timing of food choices made in the exercise context.

One step at a time: Physical activity is linked to positive interpretations of ambiguity.

BACKGROUND: Extensive research has established a clear positive relationship between physical activity (PA), even in small amounts, and psychological well-being, including benefits for emotional and mental health (e.g., decreased depression). However, little research has examined the relationship between PA and decision-making within emotionally ambiguous contexts. The purpose of the present cross-sectional study was to examine the relationship between reported amount and intensity of PA and interpretations of emotional ambiguity. METHODS: Adults (n = 611) recruited through Amazon's Mechanical Turk were assessed on their interpretations of ambiguous and clear (unambiguous) emotional stimuli and reported habitual PA and exercise. RESULTS: More positive ratings of ambiguity were associated with greater amount of vigorous activity (p = .002), but not with moderate activity (p = .826) or walking (p = .673). Subsequent analyses demonstrated that this relationship between vigorous PA and positive interpretations of ambiguity was most pronounced when comparing individuals who reported any amount of vigorous PA to those who reported no vigorous activity at all. CONCLUSIONS: Our findings suggest that higher amounts of vigorous, but not moderate, PA are associated with more positive interpretations of ambiguity, and that even small amounts of PA seem to be sufficient to promote this more positive valence bias when compared to individuals conducting no vigorous PA at all. Future work should examine the longitudinal effects of PA among individuals participating in structured activity programs.

Exercise and the Timing of Snack Choice: Healthy Snack Choice is Reduced in the Post-Exercise State.

Acute exercise can induce either a compensatory increase in food intake or a reduction in food intake, which results from appetite suppression in the post-exercise state. The timing of food choice-choosing for immediate or later consumption-has been found to influence the healthfulness of foods consumed. To examine both of these effects, we tested in our study whether the timing of food choice interacts with exposure to exercise to impact food choices such that choices would differ when made prior to or following an exercise bout. Visitors to a university recreational center were equipped with an accelerometer prior to their habitual workout regime, masking the true study purpose. As a reward, participants were presented with a snack for consumption after workout completion. Participants made their snack choice from either an apple or chocolate brownie after being pseudo-randomly assigned to choose prior to ("before") or following workout completion ("after"). Complete data were available for 256 participants (54.7% male, 22.1 ± 3.1 years, 24.7 ± 3.7 kg/m²) who exercised 65.3 ± 22.5 min/session. When compared with "before," the choice of an apple decreased (73.7% vs. 54.6%) and the choices of brownie (13.9% vs. 20.2%) or no snack (12.4% vs. 25.2%) increased in the "after" condition (χ² = 26.578, p < 0.001). Our results provide support for both compensatory eating and exercise-induced anorexia. More importantly, our findings suggest that the choice of food for post-exercise consumption can be altered through a simple behavioral intervention.

Monitoring hydration status pre- and post-training among university athletes using urine color and weight loss indicators.

OBJECTIVE: To investigate the hydration status pre- and post-training among university athletes using urine color and weight loss as indicators. PARTICIPANTS: Participants were 52 university athletes training for campus games in a developing country. METHODS: Pre- and post-training urine specimens were compared with a standard urine color scale. Paired t tests were used to compare urine color and difference in body mass pre- and post-training. RESULTS: The mean age of the athletes was 22.87 ± 3.21. A statistically significance difference (p < .01) was observed between pre- (4.31 ± 1.75) and post- (5.67 ± 1.45) training urine color values for males. Hydration status and weight post-training were statistically significantly different both at the level of p < .01. CONCLUSIONS: The results suggest that there is a link between urine color and body mass difference among the student athletes tested. Exercise increases hypohydration due to fluid losses, and therefore attention should be given to fluid supplementation and individualization of fluid intake for each athlete.

Nutritional knowledge and attitudes of adolescent swimmers in trinidad and tobago.

Purpose. To investigate the level of nutrition knowledge and attitude of adolescent male and female swimmers training competitively in Trinidad and Tobago. Methodology. A self-administered questionnaire, which consisted of 21 nutrition knowledge and 11 attitude statements, was utilized to assess the level of nutrition knowledge and attitude of adolescent swimmers. For the assessment of nutrition knowledge, correct answers were given a score of "1" and incorrect answers were given a score of "0." For the evaluation of attitude towards nutrition, a score ranging from 1 to 5 was assigned to each response; "5" was given to the most positive response, and "1" was given to the most negative. Data were analyzed using SPSS version 21.0. Results. Two hundred and twenty swimmers with a mean age of 14.56 ± 2.544 completed the questionnaire. The mean nutrition knowledge score was 10.97 ± 2.897 and mean attitude score was 41.69 ± 6.215. Nutrition knowledge was positively and significantly related to the number of reported nutrition sources (r = 0.172, P = 0.005). Nutrition knowledge was positively and significantly related to the attitude (r = 0.130, P = 0.027). Conclusions and Implication. Athletes lack nutrition knowledge but have a positive attitude towards nutrition, which may indicate receptiveness to future nutrition education.