Effects of Food Intake Sequence on Substrate Utilisation and Endurance Performance

NCT07503990 | Not Yet Recruiting

• 2 other identifiers: FOODSEQ-SUEP2022.12954.BD
• Study Type: interventional
• Target: 19
• Locations: 1 country
• Sites: 1

Brief Summary

The goal of this clinical trial is to understand how consuming a pre-exercise meal in different food intake sequences affects substrate utilisation and endurance exercise performance in healthy trained athletes. Specifically, the main questions it aims to answer are:

• Does consuming the pre-exercise meal in different food intake sequences alter the whole-body utilisation of fat and CHO at rest and during prolonged exercise at moderate to heavy intensities?
• Does consuming the pre-execise meal in different food intake sequences alter time-trial performance?
• Does consuming the pre-exercise meal in different food intake sequences alter other metabolic and physiological responses before, during or after exercise (i.e., blood glucose, blood lactate, heart rate (HR), ratings of perceived exertion (RPE), appetite)? To address these questions, researchers will compare eating the dietary sources of rapidly absorbed CHO at the end (CHO-last meal pattern) or at the start (CHO-first meal pattern) of a standardised pre-exercise meal, in a randomised, counterbalanced, crossover design. Two hours after starting the pre-exercise meal, participants will perform a 60-min submaximal test on a cycling ergometer at two different intensities (30 min at 90% of the ventilatory threshold (VT) 1 and 30 min at 50% VT1-VT2), followed by a 10-km cycling time trial (TT). In the screening visit participants will:
• Be screened for cardiometabolic conditions
• Perform an 8-12-min graded exercise test to determine their maximal pulmonary oxygen uptake (VO2max) and non-invasive submaximal anchors of performance (VT 1 and VT 2)
• Be familiarised to the experimental procedures In experimental visits participants will:
• Follow guidelines pertaining to dietary intake, exercise and sleep in the previous 24 hours
• Have a standardised test meal in either the CHO-last or CHO-first food intake sequence
• Have 3 drops of capillary blood (0,9 µL in total) collected to measure glucose and lactate pre-meal, 15, 30, 45, 60, 90 and 120 min post-meal, every 15 min during submaximal exercise and post-TT
• Breathe into an indirect calorimetry mask for 5 min pre-meal, 15, 30, 45, 60, 90 and 120 min post-meal, every 15 min during submaximal exercise and post-TT
• Wear a HR monitor continuously during submaximal exercise and the TT
• Rate their appetite on visual analogue scales pre-meal, 15, 30, 45, 60, 90 and 120 min post-meal, and 30 min post-TT
• Rate their perceived exertion on RPE scales every 15 min during submaximal exercise, post-TT and 30 min post-TT. Data will be compared within-participant between food intake sequences using linear mixed-effects models with random intercepts, to account for repeated measurements, interindividual variability, and potential missing data.

Conditions

Substrate Metabolism; Healthy Participants; Endurance Exercise

Keywords

food order; meal sequence; glucose metabolism; substrate utilisation; sport nutrition

Outcome Measures

Primary Outcomes (2)

• Whole-body fat oxidation

  Difference between CHO-last and CHO-first meal patterns in the whole-body fat oxidation rate (g/min) over time adjusted for baseline, measured by indirect calorimetry.

  Every 15 minutes post-meal (0-120 minutes), every 15 minutes throughout the subsequent standardised exercise protocol (120-180 minutes)

• Time-trial performance

  Difference between CHO-last and CHO-first meal patterns in the time to complete (min:sec) a 10-km cycling TT, assessed using a validated cycle ergometer.

  Immediately upon completion of the time trial subsequent to the post-meal resting period (0-120 minutes) and standardised exercise protocol (120-180 minutes)

Secondary Outcomes (9)

• Time-trial power output

  Immediately upon completion of the time trial subsequent to the post-meal resting period (0-120 minutes) and standardised exercise protocol (120-180 minutes)

• Whole-body CHO oxidation

  Every 15 minutes post-meal (0-120 minutes), every 15 minutes throughout the subsequent standardised exercise protocol (120-180 minutes)

• Respiratory exchange ratio (RER)

  Every 15 minutes post-meal (0-120 minutes), every 15 minutes throughout the subsequent standardised exercise protocol (120-180 minutes)

• Energy expenditure

  Every 15 minutes post-meal (0-120 minutes), every 15 minutes throughout the subsequent standardised exercise protocol (120-180 minutes)

• Blood glucose concentrations

  Every 15 minutes post-meal in the first hour (0-60 min), every 30 minutes in the second hour (60-120 min), every 15 minutes throughout the standardised exercise protocol (120-180 min) and immediately upon completion of the subsequent time trial

Study Arms (2)

CL-CF

EXPERIMENTAL

The interventions (carbohydrate-last meal pattern (CL) or carbohydrate-first meal pattern (CF)) will be delivered in random order at two study visits, separated by a wash-out period of at least 7 days. If participants are allocated to this study arm, they will receive the CL on the first visit and the CF on the second visit. The nutritional composition of the test-meal will comply to the current sports nutrition guidelines for the pre-exercise meal (i.e., 1-4 g of CHO/kg of body mass, moderate amounts of protein, low-fat and fibre content, 5-10 mL/kg of body mass of fluids) (Thomas et al., 2016). Participants will be encouraged to consume the meal in full within 15 minutes, at a comfortable pace, to mimic real eating circumstances.

Other: Carbohydrate-last meal pattern; Other: Carbohydrate-first meal pattern

CF-CL

ACTIVE COMPARATOR

The interventions (carbohydrate-last meal pattern (CL) or carbohydrate-first meal pattern (CF)) will be delivered in random order at two study visits, separated by a wash-out period of at least 7 days. If participants are allocated to this study arm, they will receive the CF on the first visit and the CL on the second visit. The test-meal will be identical and isocaloric in both interventions of the study.

Other: Carbohydrate-last meal pattern; Other: Carbohydrate-first meal pattern

Interventions

Carbohydrate-last meal pattern OTHER

Skyr yoghurt, whey protein and almonds over \~5 min, immediately followed by white bread, strawberry jam, banana and pulp-free orange juice over \~10 min.

Also known as: CHO-last, CL

CF-CL; CL-CF

Carbohydrate-first meal pattern OTHER

White bread, strawberry jam, banana and pulp-free orange juice over \~10 min, immediately followed by skyr yoghurt, whey protein and almonds over \~5 min.

Also known as: CHO-first, CF

CF-CL; CL-CF

Eligibility Criteria

• Age: 18 Years - 64 Years
• Gender Eligibility Details: Cisgender
• Healthy Volunteers: Yes
• Age Groups: Adult (18-64)

You may qualify if:

• Adult (18-64 years old)
• Men
• Endurance-trained athletes (meeting training and performance caliber criteria ≥Tier 2; McKay et al., 2022)

You may not qualify if:

• Normal glucose tolerant according to the latest criteria established by the American Diabetes Association (2024): HbA1c \<5.7%, fasting plasma glucose \<5.6 mmol/L (100 mg/dL) or 2-h plasma glucose \<7.8 mmol/L (140 mg/dL) during a 75-g OGTT
• Able and willing to provide informed consent and safely comply with study procedures
• Any medical condition or behaviour deemed either to pose undue personal risk to the participant or introduce bias into the experiment (e.g. cardiovascular disease; alcohol or substance abuse; any condition affecting the glucose or lipid metabolism, reviewed on a case by case basis)
• Any reported medication or supplementation that may interfere with the glucose metabolism (e.g., acarbose, insulin, metformin, semaglutide, thiazolidinediones, sulfonylureas, corticosteroids, thiazide diuretics) or lipid metabolism (e.g., statins, nicotinic acid, colestyramine anhydrous, ezetimibe, fibrates, L-carnitine). Other medication and supplementation will be reviewed on a case by case basis.
• Known food allergy, intolerance or hypersensitivity to any of the test meal ingredients
• Recent change in body mass (± 2 kg in the last 2 months)
• Smoking

Sponsors & Collaborators

• Universidade do Porto: lead
• Federação Portuguesa de Futebol: collaborator
• Fundação para a Ciência e a Tecnologia: collaborator

Study Sites (1)

Cidade do Futebol

Lisbon, Oeiras, 1495-433, Portugal

Location

Study Officials

• Rita Giro

  FCNAUP, University of Porto; Federação Portuguesa de Futebol

  PRINCIPAL INVESTIGATOR

Central Study Contacts

Rita Giro

CONTACT

225074320; up201307940@edu.fcna.up.pt

João Brito, PhD

CONTACT

joao.brito@fpf.pt

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: SINGLE
• Who Masked: OUTCOMES ASSESSOR
• Masking Details: Although participants and the researcher delivering the test meal will be able to see the ingredients and the order in which they are consumed, outcome assessors of subjective (e.g. RPE, appetite) and performance data will be blinded to the intervention sequence. Furthermore, participants will be blinded to their performance results during both study sessions.
• Purpose: BASIC SCIENCE
• Intervention Model: CROSSOVER
• Sponsor Type: OTHER
• Responsible Party: SPONSOR

Model Details: This study is designed as a randomised, counterbalanced, crossover, superiority trial with two groups. Block randomization will be performed by an external researcher with a 1:1 allocation ratio, and allocation concealment will be ensured through the use of sequentially numbered, opaque, sealed envelopes.

Study Record Dates

• First Submitted: November 14, 2025
• First Posted: March 31, 2026
• Study Start: April 1, 2026
• Primary Completion (Estimated): July 1, 2026
• Study Completion (Estimated): July 1, 2026
• Last Updated: March 31, 2026

Record last verified: 2026-03

Data Sharing

• IPD Sharing: Will share
• Shared Documents: SAP, ICF
• Time Frame: IPD will become accessible following the publication of all study findings.
• Access Criteria: IPD will be made available to researchers with legitimate scientific purposes (such as systematic reviews or meta-analyses).

Locations

PT (1)