Effect of Isocaloric Ketogenic Diet on Physical Performance at High Altitude (ICKD)

Effect of a Four-week Isocaloric Ketogenic Diet on Physical Performance at Very High Altitude: a Pilot Study

A ketogenic diet (KD) reduces daily carbohydrates (CHOs) ingestion by replacing most calories with fat. KD is of increasing interest among athletes because it may increase their maximal oxygen uptake (VO2max), the principal performance limitation at high altitudes. The investigators examined the tolerance of a 4-week isocaloric KD (ICKD) under simulated hypoxia and the possibility of evaluating ICKD performance benefits with a maximal graded exercise bike test under hypoxia and collected data on the effect of the diet on performance markers and arterial blood gases.

Study Overview

• Status: Completed
• Conditions: Physical Activity; Ketogenic Dieting; Altitude Hypoxia
• Intervention / Treatment: Dietary supplement: Isocaloric ketogenic diet

Detailed Description

In a randomised single-blind cross-over model, 6 recreational mountaineers (age 24 to 44 years) will complete a 4-week ICKD followed or preceded by a 4-week habitual mixed western diet (HD). Performance parameters (VO2max, lactate threshold [LT], peak power [Ppeak]) and arterial blood gases (PaO2, PaCO2, pH, HCO3-) will be measured at baseline under two conditions (normoxia and hypoxia) as well as after a 4-week HD and 4-week ICKD under the hypoxic condition.

• Study Type: Interventional
• Enrollment (Actual): 8
• Phase: Not Applicable

Contacts and Locations

Study Locations

• Switzerland
  • Sion, Switzerland, 1951
    • CRR

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years to 43 years (Adult)
• Accepts Healthy Volunteers: No
• Genders Eligible for Study: All

Description

Inclusion Criteria:

• Recreational mountaineers
• Familiarity with altitude (>2500 m above sea level) and males/females 20 to 45 years old.

Exclusion Criteria:

• high training load (such as professional athletes) or new planned training
• dietary restrictions.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Basic Science
• Allocation: Randomized
• Interventional Model: Crossover Assignment
• Masking: Single

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Active Comparator: Normal diet; no limitations on food consumption.	Dietary supplement: Isocaloric ketogenic diet; The ICKD definition was based on the works of Sansone (2018) and Trimboli (2020). We defined ICKD as a daily CHOs ingestion < 30 to 50 g.d-1, without any limitation in fat consumption. Participants self-selected their own diet based on a list of advised and forbidden foods developed to fit the definition of ICKD. There were no instructions to limit calories.
Experimental: Isocaloric ketogenic diet; We defined ICKD as a daily CHOs ingestion < 30 to 50 g.d-1, without any limitation in fat consumption.	Dietary supplement: Isocaloric ketogenic diet; The ICKD definition was based on the works of Sansone (2018) and Trimboli (2020). We defined ICKD as a daily CHOs ingestion < 30 to 50 g.d-1, without any limitation in fat consumption. Participants self-selected their own diet based on a list of advised and forbidden foods developed to fit the definition of ICKD. There were no instructions to limit calories.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Performance test under hypoxic conditions	VO2max cycling test on ergometer	after 4 weeks of diet

Collaborators and Investigators

• Sponsor: Clinique Romande de Readaptation
• Investigators: Study Director: Lara Allet, PhD, HESso

Study record dates

Study Major Dates

• Study Start (Actual): September 1, 2020
• Primary Completion (Actual): September 1, 2021
• Study Completion (Actual): September 23, 2022

Study Registration Dates

• First Submitted: October 26, 2022
• First Submitted That Met QC Criteria: October 31, 2022
• First Posted (Actual): November 3, 2022

Study Record Updates

• Last Update Posted (Actual): November 3, 2022
• Last Update Submitted That Met QC Criteria: October 31, 2022
• Last Verified: October 1, 2022

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Respiratory Tract Diseases; Respiration Disorders; Signs and Symptoms, Respiratory; Altitude Sickness; Hypoxia
• Other Study ID Numbers: CRR

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: No

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No