Effects of Steady State and High-Intensity Exercise on Compensatory Eating Behavior Study Notes

Study Introduction and Purpose

  • Research Focus: The study investigates the effects of an acute bout of High-Intensity Intermittent (HI) exercise and vigorous-intensity Steady State (SS) exercise on compensatory eating behaviors.
  • Context of Weight Management: Exercise is a critical tool for managing body weight and obesity-related comorbidities. It is frequently prescribed alongside dietary modifications. However, weight management programs often fail to produce favorable changes in mass or composition, potentially due to individualistic responses like compensatory eating.
  • Research Gap: Few studies have examined the acute effects of compensatory eating in trained, healthy individuals or the specific effect of intensity on macronutrient selection.
  • Theoretic Basis (Hormonal Regulation):
    • Exercise is known to influence appetite via the gastrointestinal tract.
    • Anorexigenic Hormones: Exercise increases levels of Cholecystokinin (CCK), Polypeptide YY (PYY), and Glucagon-like peptide-1 (GLP-1).
    • Orexigenic Hormones: Exercise decreases appetite-stimulating hormones such as Acylated Ghrelin (AG).
    • Theoretically, individuals should benefit from the double effect of caloric expenditure during exercise and eating less post-exercise. Reality often differs, with mixed results in existing literature.

Scientific Methods and Participant Demographics

  • Participants Profile (n=9n=9):
    • Gender Distribution: 3 males and 6 females.
    • Community Source: East Stroudsburg University community recruitment via word of mouth.
    • Age: 23.6±1.323.6 \pm 1.3 years old.
    • Activity Level: Recreationally active with a mean V˙O2max\dot{V}O_2max of 47.0±2.9 ml/kg/min47.0 \pm 2.9\,ml/kg/min.
    • Physical Metrics:
      • BMI: 24±0.7 kg/m224 \pm 0.7\,kg/m^2.
      • Weight: 148±7 lb148 \pm 7\,lb.
      • Height: 66±1 in66 \pm 1\,in.
      • Body Fat: 20±2%20 \pm 2\%.
    • Inclusion Criteria: Non-smokers, non-obese, weight stable for the past 6 months, no dietary supplements, and free of cardiovascular, metabolic, or renal diseases.

Preliminary Assessments and Trial Standardization

  • Screening and Blinding: Subjects completed a written informed consent and a Physical Activity Readiness Questionnaire (PAR-Q). Subjects were notably blinded to the true purpose of the study to prevent intentional food selection; they were told the study evaluated heart rate (HR) responses to exercise structures.
  • Anthropometry: Weight assessed on a Detecto physician's scale; height assessed via a wall-mounted stadiometer; body composition assessed via air-displacement plethysmography (BOD POD®).
  • V˙O2max\dot{V}O_2max Testing (Bruce Protocol):
    • Equipment: Quinton® TM55 motorized treadmill and Parvo Medics TrueOne 2400 metabolic cart.
    • Validity Criteria for Test:
      • V˙O2\dot{V}O_2 increase <50 ml/min< 50\,ml/min with increasing workload.
      • Rate of Perceived Exertion (RPE) ≥17\ge 17 on the Borg Scale.
      • HR surpassing 85%85\% of age-predicted maximum.
  • Calculations: Treadmill speeds for workloads (50%50\%, 70%70\%, and 90%90\% of predetermined V˙O2max\dot{V}O_2max) were calculated using ACSM metabolic equations for running/walking at 0%0\% grade. Resting V˙O2\dot{V}O_2 was assumed to be 3.5 ml/kg/min3.5\,ml/kg/min.

Exercise and Control Trial Protocols

  • Randomization: Order of trials was randomized, and subjects were not told which trial would occur on a given day. Trials were performed on the same day of the week for three consecutive weeks.
  • Trial Conditions:
    1. Steady State (SS): Run for 33 minutes at a speed corresponding to 70%70\% of predetermined V˙O2max\dot{V}O_2max.
    2. High-Intensity Intermittent (HI): Total of 34 minutes, alternating between 1 minute of running at 90%90\% V˙O2max\dot{V}O_2max and 1 minute of walking at 50%50\% V˙O2max\dot{V}O_2max.
    3. Control (CON): Sitting quietly in a chair for 34 minutes.
  • Standardization Measures:
    • Subjects could not view running speeds or trial time (no time-keeping devices allowed).
    • Subjects reported in an 8-10 hour fasted state between 6:00 am and 8:00 am.
    • Refrained from strenuous exercise 24 hours prior.
    • Pre-Trial Nutrition: Upon arrival, subjects consumed 20 oz20\,oz of orange or fruit punch Gatorade® (140 kcal140\,kcal, 36 g36\,g carbohydrate, 0 g0\,g fat, 0 g0\,g protein) within 10 minutes, then sat for 60 minutes before exercising.
    • Warm-up/Cool-down: 5 minutes at 50%50\% V˙O2max\dot{V}O_2max before and after the main bout.

Nutritional Intake Monitoring

  • Dietary Documentation: Subjects logged food intake 24 hours prior and 24 hours after each session.
  • Tools: MyFitnessPal app/website and photographs of all food/drink consumed to verify logs.
  • Nutrients Analyzed: Daily caloric intake (kcalkcal), Carbohydrates (CHOCHO), Protein (PROPRO), and Fat (FATFAT).

Results: Exercise Session Physiological Data

  • Energy Expenditure (EE):
    • CON: 77±10 kcal77 \pm 10\,kcal
    • HI: 321±73 kcal321 \pm 73\,kcal
    • SS: 345±73 kcal345 \pm 73\,kcal
    • Statistical Significance: CON was significantly lower than HI and SS (p<0.001p < 0.001). No difference between HI and SS (p=0.49p = 0.49).
  • Rate of Perceived Exertion (RPE):
    • CON: 6±06 \pm 0
    • HI: 14±314 \pm 3
    • SS: 14±114 \pm 1
    • Statistical Significance: CON significantly lower (p<0.001p < 0.001). No difference between HI and SS (p=0.81p = 0.81).
  • Heart Rate (HR):
    • CON: 68±10 bpm68 \pm 10\,bpm
    • HI: 156±22 bpm156 \pm 22\,bpm
    • SS: 157±21 bpm157 \pm 21\,bpm
    • Statistical Significance: CON significantly lower (p<0.001p < 0.001). No difference between HI and SS (p=0.67p = 0.67).

Results: Detailed Dietary and Macronutrient Intake

  • Total Caloric Intake (Comparison Pre vs. Post):
    • CON trial: 1614±106 kcal1614 \pm 106\,kcal (Pre) -> 1557±172 kcal1557 \pm 172\,kcal (Post); Effect Size d=−0.13d = -0.13.
    • HI trial: 1553±114 kcal1553 \pm 114\,kcal (Pre) -> 1850±150 kcal1850 \pm 150\,kcal (Post); Effect Size d=0.74d = 0.74 (medium-large).
    • SS trial: 1567±158 kcal1567 \pm 158\,kcal (Pre) -> 1683±143 kcal1683 \pm 143\,kcal (Post); Effect Size d=0.26d = 0.26.
    • ANOVA result: No significant difference between groups (p=0.42p = 0.42).
  • Carbohydrate (CHO) Intake:
    • CON: 172±13 g172 \pm 13\,g (Pre) -> 186±25 g186 \pm 25\,g (Post); Effect Size d=−0.24d = -0.24.
    • HI: 166±19 g166 \pm 19\,g (Pre) -> 225±24 g225 \pm 24\,g (Post); Effect Size d=0.91d = 0.91 (large-very large).
    • SS: 185±18 g185 \pm 18\,g (Pre) -> 201±23 g201 \pm 23\,g (Post); Effect Size d=0.27d = 0.27.
    • ANOVA result: No significant difference between groups (p=0.66p = 0.66).
  • Protein (PRO) Intake:
    • CON: 68±10 g68 \pm 10\,g (Pre) -> 57±5 g57 \pm 5\,g (Post); Effect Size d=−0.01d = -0.01.
    • HI: 40±6 g40 \pm 6\,g (Pre) -> 61±6 g61 \pm 6\,g (Post); Effect Size d=−0.21d = -0.21.
    • SS: 73±12 g73 \pm 12\,g (Pre) -> 72±8 g72 \pm 8\,g (Post); Effect Size d=−0.58d = -0.58 (medium-large decrease).
    • ANOVA result: No significant difference between groups (p=0.82p = 0.82).
  • Fat (FAT) Intake:
    • CON: 66±9 g66 \pm 9\,g (Pre) -> 63±5 g63 \pm 5\,g (Post); Effect Size d=−0.41d = -0.41.
    • HI: 65±8 g65 \pm 8\,g (Pre) -> 73±9 g73 \pm 9\,g (Post); Effect Size d=−0.28d = -0.28.
    • SS: 62±10 g62 \pm 10\,g (Pre) -> 66±9 g66 \pm 9\,g (Post); Effect Size d=0.05d = 0.05.
    • ANOVA result: No significant difference between groups (p=0.30p = 0.30).

Discussion and Practical Implications

  • Nutritional Compensation Analysis:
    • Following HI exercise, subjects increased energy intake by 297 kcal297\,kcal. Since the calorie expenditure of the bout was 321 kcal321\,kcal, the net deficit was only 24 kcal24\,kcal.
    • Following SS exercise, subjects increased intake by 116 kcal116\,kcal. Given an expenditure of 345 kcal345\,kcal, a net deficit of 229 kcal229\,kcal was achieved.
    • This suggests that while HI exercise is popular, it may trigger compensatory eating that offsets much of the caloric burn, making SS potentially more effective for weight loss in this population.
  • Applicability of HIIT: HIIT has been globally popular since 2014. Despite its efficiency and enjoyment factors, practitioners should be aware of possible increases in carbohydrate-specific compensatory eating.
  • Comparison to Literature: The findings of increased intake after HI contrast with studies like Sim et al., which showed lower intake after high-intensity exercise in overweight men. However, the Sim et al. study used liquid meals in a laboratory setting, whereas this study used free-living "eat at will" conditions.

Study Limitations

  • Menstrual Cycle: The study did not control for menstrual phases or abnormalities. Literature suggests higher caloric/macronutrient intake during the luteal phase compared to the follicular phase.
  • Participant Characteristics: Subjects were non-obese and recreationally active. Appetite-regulating hormones (like Leptin and Ghrelin) behave differently in obese individuals.
  • Recovery Energy Expenditure: The study did not measure energy expenditure during the post-exercise recovery period, focusing only on the 24-hour intake logs.
  • Chronic vs. Acute: This research focused on a single acute bout; chronic exercise training may yield different behavioral adaptations.

Conclusions

  • Acute high-intensity intermittent exercise did not lead to statistically significant differences in compensatory eating behaviors compared to isocaloric steady-state exercise.
  • Meaningful effect sizes suggest HI exercise may specifically trigger increased carbohydrate consumption.
  • Practitioners can generally recommend different exercise models, but should monitor potential overeating when HIIT protocols are used for weight management goals.