Endocrinological and Physiological Responses to Short-term Reduced Carbohydrate Availability in Males

NCT05551455 | Completed

• 1 other identifier: 22/SPS/026
• Study Type: interventional
• Target: 8
• Locations: 1 country
• Sites: 1

Brief Summary

Using a randomised crossover design, nine weight-stable men, aged 18 - 40 years old, will be recruited via convenience sampling from the staff and student body of LJMU and local area. Participants will be asked to follow two 4-day (\~96 hours) periods of tightly controlled exercise energy expenditure (15 kcal/kg FFM/day \[cycling\]) and dietary intake (60 kcal/kg FFM/day) to compare a state of 'normal' energy availability (or energy balance; equivalent to 45 kcal/kg FFM/day) with concomitant 1: normal carbohydrate availability ('Normal'; \~60% of dietary intake from carbohydrate) and 2: low carbohydrate availability ('LCHF', \~1.5 g/kg carbohydrate per day, \~70 - 80% dietary intake from fat). This approximates the amount of carbohydrate consumed by an individual in a state of LEA through consuming 10 kcal/kg FFM/day with 50% of intake from carbohydrate, or \~1.5 g/kg/day of carbohydrate. In both experimental phases we will measure endocrine, metabolic and physiological parameters.

Conditions

Energy Supply; Deficiency; Carbohydrate Availability

Keywords

Bone turnover markers; Testosterone; Glucose; Glycerol; Ketones; Insulin; Leptin; Ghrelin; Triglycerides; Triiodothyronine; Thyroxine; Resting Metabolic Rate (RMR); Free fatty acids; Blood pressure; ß-CTX; P1NP

Outcome Measures

Primary Outcomes (3)

• Changes in blood bone turnover markers: ß-CTX (Bone Resorption)

  Analysis of changes in blood-borne bone (re)modelling marker ß-CTX (Bone Resorption) following short term energy balance with a) normal carbohydrate availability and b) low carbohydrate availability

  Days 1, 2, 3, 4 & 5 per intervention

• Changes in blood bone turnover markers: P1NP (Bone Formation)

  Analysis of changes in blood-borne bone (re)modelling marker P1NP (Bone Formation)

  Days 1, 2, 3, 4 & 5 per intervention

• Changes in blood metabolites/hormones: Testosterone

  Analysis of changes to circulating testosterone concentrations following short term energy balance with a) normal carbohydrate availability and b) low carbohydrate availability

  Days 1, 2, 3, 4 & 5 per intervention

Secondary Outcomes (37)

• Change in resting substrate utilisation

  Days 1, 3 and 5 of each intervention

• Changes in sub-maximal Exercise Energy Expenditure

  Days 1, 2, 3, 4 & 5 per intervention

• Changes in sub-maximal exercise substrate utilisation

  Days 1, 2, 3, 4 & 5 per intervention

• Immune function

  Days 1, 2, 3, 4 & 5 per intervention

• Changes in Initial Orthostatic Hypotension (IOH)

  Pre- and post-intervention (days 1 and 5) for both intervention

Study Arms (2)

Normal Carbohydrate Availability

OTHER

Participants will complete a supervised morning cycling session daily (each morning for five days) to achieve a 15 kcal/kg FFM/day exercise energy expenditure, with samples collected pre-, during- and post-exercise. Participants will then be provided (daily) with all subsequent dietary intake for the intervention period. In the Normal Carbohydrate Availability trial arm, participants will be provided with 60 kcal/kg FFM/day of energy intake, to elicit a net energy availability of 45 kcal/kg FFM, with \~60% of this energy intake from carbohydrates. The intervention will last for four days, spanning five testing mornings (i.e. trial begins following fasted baseline assessments on morning 1, finishing with final sample collection on morning 5).

Other: Nutritional/dietary intake manipulation ('Normal')

Low Carbohydrate Availability

EXPERIMENTAL

Participants will complete a supervised morning cycling session daily (each morning for five days) to achieve a 15 kcal/kg FFM/day exercise energy expenditure, with samples collected pre-, during- and post-exercise. Participants will then be provided (daily) with all subsequent dietary intake for the intervention period. In the Low Carbohydrate Availability trial arm, participants will be provided with 60 kcal/kg FFM/day of energy intake, to elicit an energy availability of 45 kcal/kg FFM, with \~1.5 g/kg provided from carbohydrate and \~70-80% of energy intake in the form of fat. The intervention will last for four days, spanning five testing mornings (i.e. trial begins following fasted baseline assessments on morning 1, finishing with final sample collection on morning 5).

Other: Nutritional/dietary intake manipulation ('Low')

Interventions

Nutritional/dietary intake manipulation ('Normal') OTHER

Energy Intake provision (60 kcal/kg FFM/day) to elicit 'normal' energy availability (45 kcal/kg FFM/day), with 60% from carbohydrates.

Also known as: Normal Carbohydrate Availability

Normal Carbohydrate Availability

Nutritional/dietary intake manipulation ('Low') OTHER

Energy Intake provision (60 kcal/kg FFM/day), with 1.5 g/kg of carbohydrate and 70-80% fat intake, to elicit 'low' carbohydrate availability in energy balance (45 kcal/kg FFM/day).

Also known as: Low Carbohydrate Availability

Low Carbohydrate Availability

Eligibility Criteria

• Age: 18 Years - 40 Years
• Sex: male
• Healthy Volunteers: Yes
• Age Groups: Adult (18-64)

You may qualify if:

• Gender/Sex: Male
• Age:18-40
• Healthy (as determined by pre-participation questionnaires)
• Regularly Exercising/Aerobically trained (3 + times/week, VO2max \>50 ml/kg/min), as determined through participant self-identification via recruitment email/verbal communication and baseline assessment of VO2max)
• Weight-stable (within 2 kg) for the past 6-months

You may not qualify if:

• Gender/Sex: Female/Other
• Age - \< 18 - \> 40
• Health - Deemed unable to perform exercise (assessed via PAR-Q)
• Current smoker.
• Medical Condition - Those with any previous diagnosis of; Osteoporosis/low bone mineral density, cardio-vascular disease, Diabetes Mellitus, Cerebrovascular Disease, blood-related illness/disorder, Asthma or other respiratory illness/disorder, Liver Disease, Kidney Disease, gastrointestinal disease, Eating Disorder or Disordered Eating. Those currently taking prescription medication or unwell with a cold or virus at the time of participation.
• Those unwilling to adhere to the study's methodological requirements (including adhering to alterations in diet and training - inc. alcohol abstention) from the day prior to intervention onset (24 hrs pre-intervention) to completion of follow-up assessments (day 5).
• Those following a restrictive diet (e.g. vegans)
• Those with food allergies and/or food intolerances
• Training status - Does not train 3 + times/week (over past 6 months on average) and/or have a VO2max \>50 ml/kg/min.
• Any athletes that may be tested for substances on the WADA banned substances list

Sponsors & Collaborators

• Liverpool John Moores University: lead

Study Sites (1)

Liverpool John Moores University

Liverpool, Merseyside, L3 3AF, United Kingdom

Location

MeSH Terms

Conditions

Ketosis; Insulin Resistance

Condition Hierarchy (Ancestors)

Acidosis; Acid-Base Imbalance; Metabolic Diseases; Nutritional and Metabolic Diseases; Hyperinsulinism; Glucose Metabolism Disorders

Study Officials

• Jose L Areta

  Liverpool John Moores University

  STUDY DIRECTOR

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: NONE
• Masking Details: Masking not possible as food quantity/type will vary between interventions.
• Purpose: BASIC SCIENCE
• Intervention Model: CROSSOVER
• Sponsor Type: OTHER
• Responsible Party: SPONSOR

Model Details: Participants will complete two five-day trial-arms in randomised order, with an \~10-day washout period between interventions.

Study Record Dates

• First Submitted: March 2, 2021
• First Posted: September 22, 2022
• Study Start: May 4, 2022
• Primary Completion: December 9, 2022
• Study Completion: December 9, 2022
• Last Updated: October 17, 2023

Record last verified: 2023-10

Data Sharing

• IPD Sharing: Will not share

Locations

GB (1)