Body Composition and Lipid Metabolism at Rest and During Exercise: A Cross-Sectional Analysis.

May 11, 2024 updated by: Javier Gonzalez, University of Bath

The ability to upregulate fat oxidation at appropriate times such as during fasting, low to moderate intensity exercise and after a high fat meal, is popularly advocated. This is presumably due to the perception that a high capacity to utilise fat may improve (ultra) endurance performance and help in the regulation of body fat and metabolic diseases. In accordance, impaired fat use at rest has been associated with obesity and insulin resistance (Kelley et al., 1999). However, there is inconclusive and / or a lack of systematic evidence, especially in a large diverse range of adults, exploring:

1) Whether whole body fat use during exercise is altered in individuals with overweight or obesity compared to lean individuals

3) The intra-individual variability in whole-body fat use at rest and during exercise

4) Physiological, metabolic, lifestyle and genetic characteristics that are associated with whole-body fat use at rest and during exercise

Therefore, the objectives of this study are three-fold:

  1. To explore whether whole body fat use is associated with body composition
  2. To explore associations between whole-body fat use and physiological, metabolic, lifestyle and genetic variables
  3. To assess the intra-individual variability of whole-body fat use.

This study is an observational, exploratory cross-sectional study. A wide range of 'healthy' and 'at-risk of metabolic disease' adults will be recruited.

Participants will be asked to visit a laboratory at the University of Bath four times. Visit 1 is a screening and study familiarisation visit. Visits 2 and 3 are to be completed within 7-14 days and involve lifestyle monitoring (dietary and physical activity), a one-off urine and blood sample, assessment of fuel use at rest and during exercise (the latter through an incremental graded cycling exercise test to exhaustion). Visit 4 is to assess body composition via a dual-energy x-ray absorptiometry (DEXA) scan in addition to an optional skeletal muscle and / or fat tissue biopsy.

Study Overview

Status

Completed

Conditions

Intervention / Treatment

Detailed Description

Metabolic flexibility broadly refers to the ability to utilize the right fuel source for energy (primarily either carbohydrate or fat) at the right time (Kelley and Mandarino, 2000). This was first conceptualised at the level of skeletal muscle (Kelley and Mandarino, 1990; Andres et al., 1956). A main tenant originally captured by 'metabolic flexibility' is the predominant utilization of fat as an energy source under rested post-absorptive conditions in 'healthy' individuals (Kelley et al., 1999; Kelley and Mandarino, 1990). Recently, there has been a call to extend the concept of 'metabolic flexibility' to exercising conditions (Goodpaster and Sparks, 2017; Rynders et al., 2017). Similarly to at rest, fat provides an important source of energy during low-to-moderate intensity exercise (van Loon et al., 2001; Romijn et al., 1993). Thus, in healthy individuals at the whole-body and skeletal muscle level, it is robustly characterised and accepted that fat is an important and predominant fuel source for energy under such conditions.

However, it is commonly proposed that a lower reliance upon fat as a fuel source is present in individuals with obesity and type 2 diabetes and consequently, has been implicated in the pathogenesis of such conditions (Rynders et al., 2017; Kelley and Mandarino, 2000). Alternatively, a high capacity to utilize fat under the aforementioned two situations is advocated to be a desirable trait for both athletes and non-athletes, presumably due to the perception that high rates of fat utilization may improve endurance performance and/or assist with the regulation of body fat and metabolic health. As such, much interest has been generated into upregulating fat utilization at appropriate times e.g. during fasting and low-to-moderate intensity exercise.

Correspondingly, lower resting and exercising fat use has been reported in individuals with obesity vs lean (e.g. Lanzi et al., 2014; Perez-Martin et al., 2001; Kelley et al., 1999). Furthermore, greater fat use at rest has been associated with lower future body weight and fat gain / regain (e.g. Shook et al., 2016; Seidell et al., 1992), and during exercise with reduced short term post-exercise energy intake / balance (e.g. Hopkins et al., 2012), exercise-induced fat loss (Barwell et al., 2008) and weight loss / maintenance (Dandadell et al., 2017). Importantly, however, this relationship is not always apparent with similar (e.g. Blaize et a., 2014; Croci et al., 2014) or higher (e.g. Ara et al., 2011; Goodpaster et al., 2002; Horowtiz et al., 2000) rates of fat use at rest and during exercise reported in individuals with obesity compared to lean counterparts. Furthermore, cross-sectional and prospective associations do not always exist between lower fat use and greater body weight / fat mass gain or regain (e.g. Dandanell et al., 2017; Ellis et al., 2010). Thus, despite being popularly advocated, it is currently unclear whether lower fat use at rest or during exercise predisposes or is a characteristic of excess adiposity (i.e. obesity).

The inconsistent findings could partly be due to numerous methodological discrepancies between studies such as participant characteristics, matching of comparative groups, the exercise protocol utilised and / or the assessment of body composition, lipid oxidation and cardio-respiratory fitness levels.

Therefore, through the use of well-established and respected techniques, we aim to comprehensively and systematically explore whether whole-body fat use at rest and during exercise is:

  1. Altered in individuals with overweight or obesity compared to lean individuals
  2. Further determinants / factors that may influence fat use
  3. The intra-individual variation in fat use which will help to more confidently determine the above objectives.

Study Type

Observational

Enrollment (Actual)

114

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

  • United Kingdom
      • Bath, United Kingdom, BA2 7AY
        • Department for Health, University of Bath

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

18 years to 65 years (Adult, Older Adult)

Accepts Healthy Volunteers

Yes

Sampling Method

Non-Probability Sample

Study Population

Adults

Description

Inclusion Criteria:

  • be between 18 - 65 years of age
  • male or female
  • body mass index between 18.9 - 35 kg/m2
  • be able and willing to give informed oral and written consent
  • complete and meet the defined criteria of pre-study questionnaires and screens

Exclusion Criteria:

  • Currently have or have a previous history of metabolic, cardio-pulmonary or musculoskeletal disease
  • BMI below 18.9 or above 35 kg/m2
  • Have plans to change lifestyle (diet and/or physical activity) during the study period ( 7 - 21 days)
  • Unwillingness or unable to sufficiently meet study demands

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

Cohorts and Interventions

Group / Cohort
Intervention / Treatment
Male and Female Adults
Completion of Study Protocol
Behavioral: Study Protocol

Participants will complete three study protocols 7 - 28 days apart which includes:

  • 3 x main trial days (max. 150 mins) involving body composition analysis, indirect calorimetry, a blood sample, optional muscle and / or adipose tissue biopsies and a maximal cardiorespiratory fitness test.
  • 2 x lifestyle monitoring periods (physical activity and diet) for the prior 7 days before each main trial day.
  • Maintenance of habitual habits, dietary and physical activity behaviour patterns

We are observing biological / health parameters in a group of individuals who will be assessed under resting and exercising conditions. The current study does not involve an intervention.

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Maximal rate of whole-body fat oxidation (mg/kg FFM/min)
Time Frame: 7 - 14 days
Fat free mass (FFM). Assessed during the incremental stage maximal cardio-respiratory fitness test
7 - 14 days

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Maximal rate of whole-body fat oxidation (g/min)
Time Frame: 7-14 days
Non-adjusted rate. Assessed during the incremental stage maximal cardio-respiratory fitness test
7-14 days
FATmax (% of maximum oxygen consumption)
Time Frame: 7 - 14 days
The exercise intensity that maximal rate of whole-body fat oxidation occurs at. Expressed as % of VO2peak). Assessed during the incremental stage maximal cardio-respiratory fitness test.
7 - 14 days
FATmax (% of Watt max)
Time Frame: 7 - 14 days
The exercise intensity that maximal rate of whole-body fat oxidation occurs at. Expressed as % of Watt max). Assessed during the incremental stage maximal cardio-respiratory fitness test.
7 - 14 days
FATmax (% of Heart Rate max)
Time Frame: 7 - 14 days
The exercise intensity that maximal rate of whole-body fat oxidation occurs at. expressed either as % of heart rate max). Assessed during the incremental stage maximal cardio-respiratory fitness test
7 - 14 days
Whole-body substrate oxidation rates (Carbohydrates and Lipid) during exercise
Time Frame: 7 - 14 days
Assessed during the incremental stage maximal cardio-respiratory fitness test via indirect calorimetry of expired gas samples.
7 - 14 days
Whole-body substrate oxidation rates (Carbohydrates and Lipid) at rest
Time Frame: 7 - 14 days
Assessed at rest through the participant lying in a semi-supine position via indirect calorimetry of expired gas samples.
7 - 14 days
Resting metabolic rate
Time Frame: 7 - 14 days
Assessed at rest through the participant lying in a semi-supine position via indirect calorimetry of expired gas samples.
7 - 14 days
Cardiorespiratory fitness (VO2peak)
Time Frame: 7 - 14 days
Assessed during the incremental stage maximal cardio-respiratory fitness test
7 - 14 days
Habitual Energy Intake
Time Frame: 7 - 21 days
Participants will be asked to complete a self-weighed food and drink diary before each main trial day (Visit 2 and 3) so that average daily calorie and macronutrient intake can be calculated. The procedure will be explained by the CI. This diet monitoring period must include 3 week-days, at least one 1 weekend day and the immediate 48-hrs prior to the beginning of each main trial (Visit 2 and 3). Additionally, the prior 48-hrs before Visit 2 will be replicated before Visit 3.
7 - 21 days
Habitual Energy Expenditure / Physical Activity
Time Frame: 7 - 21 days
Physical activity will be measured by accelerometry and heart-rate monitoring for 7 days before each main trial day (Visit 2 and 3). This procedure will be explained by the CI. ntake can be calculated. The participants physical activity levels for the immediate 48-hrs prior to the beginning of each main trial (Visit 2 and 3) will be asked to be replicated as closely as possible.
7 - 21 days
Menstrual Cycle (females only)
Time Frame: 7 - 21 days
Assessed through a self-reported menstrual cycle questionnaire
7 - 21 days
Self-reported Physical Activity level
Time Frame: 7-21 days
Assessed by the International Physical Activity Questionnaire (long form)
7-21 days
Fasting glucose concentration
Time Frame: 7-21 days
Assessed via plasma sample extracted from the blood sample
7-21 days
Fasting lipid profiles (triglycerides / cholesterol)
Time Frame: 7-21 days
Assessed via serum sample extracted from the blood sample
7-21 days
Fasting Adipose tissue derived hormone concentrations (leptin, adiponectin)
Time Frame: 7-21 days
Assessed via plasma sample extracted from the blood sample
7-21 days
Fasting catecholamine concentrations (epinephrine and norepinephrine)
Time Frame: 7-21 days
Assessed via plasma sample extracted from the blood sample
7-21 days
Fasting sex hormone concentrations (17 beta-estradiol, testosterone, progesterone)
Time Frame: 7-21 days
Assessed via serum sample extracted from the blood sample
7-21 days
Fasting pancreatic derived hormone concentrations (insulin and glucagon)
Time Frame: 7-21 days
Assessed via plasma sample extracted from the blood sample
7-21 days
Hydration Status (urine specific gravity)
Time Frame: 7-21 days
Assessed via analysis of urine sample with a refractometer
7-21 days
Age
Time Frame: 7-21 days
Assessed via a participant questionnaire
7-21 days
Sex
Time Frame: 7-21 days
Assessed via a participant questionnaire
7-21 days
Ethnicity
Time Frame: 7-21 days
Assessed via a participant questionnaire
7-21 days
Smoking Status
Time Frame: 7-21 days
Assessed via a participant questionnaire
7-21 days
Medication / supplement use
Time Frame: 7-21 days
Assessed via a participant questionnaire
7-21 days
Dietary pattern / requirements (e.g. vegetarian, vegan, Celiac disease)
Time Frame: 7-21 days
Assessed via a participant questionnaire
7-21 days
Body Mass (kg)
Time Frame: 7-21 days
Assessed via body weighing scales
7-21 days
Body Mass Index (kg/m2)
Time Frame: 7-21 days
Assessed by dividing body weight in kg by height in metres squared.
7-21 days
Waist circumference (cm)
Time Frame: 7-21 days
Assessed via use of an anthropometric tape measure
7-21 days
Hip Circumference (cm)
Time Frame: 7-21 days
Assessed via use of an anthropometric tape measure
7-21 days
Body fat percentage
Time Frame: 1 day
Assessed via a dual energy xray absorptiometry scan at Visit 4.
1 day
Body fat localisation
Time Frame: 1 day
Assessed via a dual energy xray absorptiometry scan at Visit 4.
1 day
Lean body mass
Time Frame: 1 day
Assessed via a dual energy xray absorptiometry scan at Visit 4.
1 day
Body fat percentage
Time Frame: 7-21 days
Bioelectrical Impedance Analysis from the body weighing scales
7-21 days
Genotyping analysis
Time Frame: 7 - 21 days
Genotyping analysis will be assessed through the extraction of the buffy coat layer from the blood sample
7 - 21 days
Skeletal Muscle sample (Optional)
Time Frame: 1 day
The optional muscle sample will be obtained from the quadriceps muscle using the Bergstrom technique on Visit 4.
1 day
Adipose Tissue (Fat) sample (Optional)
Time Frame: 1 day
The optional fat sample will be obtained from the subcutaneous abdominal region (5 cm laterally of the umbilicus) via the 'lipoaspiration' technique on Visit 4.
1 day
Fat mass index (body fat in kg/m2)
Time Frame: 7 - 21 days
Assessed by dividing body fat in kg by height in metres squared.
7 - 21 days

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

University of Bath

Investigators

  • Principal Investigator: Javier T Gonzalez, PhD, University of Bath

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

January 8, 2018

Primary Completion (Actual)

May 28, 2019

Study Completion (Actual)

May 11, 2024

Study Registration Dates

First Submitted

January 14, 2017

First Submitted That Met QC Criteria

January 19, 2017

First Posted (Estimated)

January 24, 2017

Study Record Updates

Last Update Posted (Actual)

May 14, 2024

Last Update Submitted That Met QC Criteria

May 11, 2024

Last Verified

May 1, 2024

More Information

Terms related to this study

Keywords

Other Study ID Numbers

  • 17/SW/0269

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

UNDECIDED

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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