Post-exercise dietary macronutrient composition modulates components of energy balance in young, physically active adults

Effects of overnight-fasted versus fed-state exercise on the components of energy balance and interstitial glucose across four days in healthy adults

Exercise is an essential component of body mass management interventions. Overnight-fasted exercise (FASTex) acutely enhances fat oxidation compared with fed exercise (FEDex). However, consistent FASTex training does not typically further enhance body mass loss, suggesting the induction of energy compensation responses. The present study aimed to test the effects of FASTex or FEDex on the components of energy balance (i.e., energy intake (EI), energy expenditure (EE), and appetite) and interstitial glucose metrics across four days.

METHODS

Twelve (10 men, 2 women) healthy, physically active participants (age 22.6 + 1.2 years (mean ± SD); BMI 22.5 ± 2.8 kg ⋅ m-2) were studied twice, across four days, after a 75-min run either FASTex or FEDex. Daily EI was obtained after subtracting leftovers from the provided food. Daily fasting appetite was measured by visual analogue scales. Activity- and total- EE (AEE & TEE, respectively) were estimated by combining heart rate and accelerometry. Continuous glucose monitoring was used to capture daily interstitial glucose metrics and Likert scales were utilised to quantify fatigue, stress, sleep quality, and muscle soreness levels.

RESULTS

No differences between conditions were observed for EI (FASTex = 15.0 ± 0.1 vs FEDex = 15.0 ± 0.4 MJ⋅day-1; p = 0.865), AEE (FASTex = 7.6 ± 1.1 vs FEDex 7.8 ± 1.3 MJ⋅day-1; p = 0.223) and TEE (FASTex = 15.9 ± 3.4 vs 14.9 ± 4.5 MJ⋅day-1; p = 0.136). Additionally, no condition effects for appetite (p > 0.05) and interstitial glucose (p = 0.074) were observed.

CONCLUSION

FASTex did not differ from FEDex in the response of components of energy balance or interstitial glucose across four days, suggesting that both exercise approaches could be used interchangeably.

Effectiveness of high-fat and high-carbohydrate diets on body composition and maximal strength after 15 weeks of resistance training

PURPOSE

The aim of this study was to compare High Carbohydrates Low Fat (HCLF) and Low Carbohydrate High Fat (LCHF) diets in terms of changes in body composition and maximal strength.

PATIENTS/METHODS

The study involved 48 men aged 25 ​± ​2.5, divided into two groups, one of which (n ​= ​23) was following the LCHF diet and the other (n ​= ​25) the HCLF diet. Both groups performed the same resistance training protocol for 15 weeks. Maximal strength in squat, bench press and deadlift was assessed pre- and post-intervention. Measurements of selected body circumferences and tissue parameters were made using the multifunctional, multi-frequency, direct bioelectric impedance InBody 770 analyzer from InBody Co., Ltd (Cerritos, California, USA). The team with the necessary qualifications and experience in research performed all the measurements and maintained participants' oversight throughout the entire length of the study.

RESULTS

Both nutritional approaches were effective in terms of reducing body fat mass. The HCLF group achieved greater skeletal muscle hypertrophy. Significant decreases in body circumferences, especially in the abdominal area, were observed for both dietary approaches. Maximal strength significantly increased in the HCLF group and decreased in the LCHF group.

CONCLUSION

Holistic analysis of the results led to the conclusion that both dietary approaches may elicit positive adaptations in body composition. The two approaches constitute useful alternatives for both recreational exercisers and physique athletes with body composition goals.