Acute Responses to Dietary Carbohydrate Manipulation

June 16, 2021 updated by: Javier Gonzalez, University of Bath

The Acute Responses to Manipulating Dietary Carbohydrate Content and Type on All Major Aspects of Energy Balance

Sugar is perceived negatively, leading to government taxation and targets to reduce consumption. These actions have been taken based on the limited evidence that high-sugar diets are associated with greater total energy intake. However, energy intake comprises just one half of the energy balance equation (e.g. balance = intake - expenditure). Without considering energy expenditure, it is impossible to understand the effects of sugar on health. Sugar, and perhaps total carbohydrate intake, may be important for energy balance - perhaps by stimulating increased energy expenditure.

Understanding dietary regulators of energy balance is more important than ever before, because diseases like obesity are a consequence of energy surplus (i.e. energy intake > energy expenditure). No studies have investigated a causal role of dietary sugar or carbohydrate on energy balance. The proposed research will seek to understand the acute (e.g. 24-hour) responses to manipulating dietary carbohydrate and sugar content on energy balance and health.

This research will contribute to enabling individuals to make informed dietary choices about carbohydrate and sugar consumption.

To achieve this, healthy non-obese adults will be recruited to a randomised crossover study. Measures of energy intake, energy expenditure, metabolic health, appetite, food preference, and gut microbiota will be taken. All laboratory trials will take place at the University of Bath.

Three diets will be investigated:

  1. Control - reflecting the composition of a typical European diet
  2. Low sugar - the same composition of a typical European diet but with <5% energy intake from sugar
  3. Low carbohydrate - low carbohydrate diet with <5% energy intake from sugar and <8% energy intake from carbohydrate, replacing carbohydrate energy with fat

The study will consist of a 3-day lead-in period with the control diet followed by one trial day with each diet.

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Completed

Conditions

Conditions

The disease, disorder, syndrome, illness, or injury that is being studied. On ClinicalTrials.gov, conditions may also include other health-related issues, such as lifespan, quality of life, and health risks.

Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.

Detailed Description

Dietary sugar is increasingly perceived in a negative way. This has led to taxation by government and guidelines by global public health bodies to reduce sugar intake to <5% of energy intake. All available public health guidelines regarding sugar advocate a reduction in sugar intake, despite a lack of evidence to support these recommendations. These guidelines focus on the association between sugar intake and energy intake, without regard for energy expenditure. This oversimplifies situations in which energy surplus is pathological, for example in diseases like obesity. This complexity is demonstrated by evidence that dietary sugar intake is decreasing in the United Kingdom, whilst rates of obesity have increased in the same timeframe.

It is important to consider energy expenditure in the context of health. The most variable component of energy expenditure between individuals is physical activity energy expenditure (PAEE), which varies from ~600-2100 kcal per day in men of a similar demographic. Current guidelines do not regard the effect that changing dietary sugar might have on PAEE and therefore total energy expenditure.

Carbohydrate availability dictates the capacity to perform physical work. However, the role of carbohydrate in regulating physical activity behaviours has only recently been considered. Ingestion of a carbohydrate-rich breakfast causes a significant increase in 24-hour PAEE compared with no breakfast consumption before midday. The magnitude of this difference is greatest prior to midday, near to when carbohydrate had been ingested and when glucose uptake to peripheral tissue is increased. This points towards a stimulatory role of carbohydrate or sugar on PAEE when carbohydrate is readily available to peripheral tissue. The amount of carbohydrate present in skeletal muscle is dictated by the amount of carbohydrate in the diet. As physical activity is performed by skeletal muscle, dietary carbohydrate intake may regulate physical activity behaviour. Consequently, reducing total carbohydrate intake may result in reduced PAEE.

Studies in which carbohydrate has been manipulated and physical activity has been measured have not been sufficient in answering this research question. Often self-report measures of physical activity are used, which are not sensitive enough to discern meaningful differences. Studies which have measured physical activity objectively, i.e. using pedometers or accelerometers, are confounded by a lack of information about actual carbohydrate intake or concurrent prescription of exercise interventions. Furthermore, government targets of reduced sugar intake to <5% of total energy intake are not aimed at overall carbohydrate intake per se. In the breakfast study mentioned, sugar intake was significantly greater amongst individuals who ate breakfast compared with individuals who fasted until midday. Therefore, it is also plausible that a regulatory role of carbohydrate on PAEE may be due to the type of carbohydrate rather than the absolute amount.

If the availability of carbohydrate to peripheral tissue plays a regulatory role on PAEE, then theoretically the effects of manipulating the amount or type of carbohydrate will be detectable acutely, within 24 hours.

Study Type

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Interventional

Enrollment (Actual)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
25

Phase

Phase

The stage of a clinical trial studying a drug or biological product, based on definitions developed by the U.S. Food and Drug Administration (FDA). The phase is based on the study's objective, the number of participants, and other characteristics. There are five phases: Early Phase 1 (formerly listed as Phase 0), Phase 1, Phase 2, Phase 3, and Phase 4. Not Applicable is used to describe trials without FDA-defined phases, including trials of devices or behavioral interventions.
  • Not Applicable

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

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

Ages Eligible for Study

18 years to 65 years (Adult, Older Adult)

Accepts Healthy Volunteers

Yes

Genders Eligible for Study

All

Description

Inclusion Criteria:

  • Body mass index 18.5-29.9 kg∙m-2
  • Age 18-65 years
  • Able and willing to provide informed consent and safely comply with study procedures
  • Females to maintain record of regular menstrual cycle phase or contraceptive use
  • No anticipated changes in diet/physical activity during the study (e.g. holidays or diet plans)

Exclusion Criteria:

  • Any reported condition or behaviour deemed either to pose undue personal risk to the participant or introduce bias
  • Any diagnosed metabolic disease (e.g. type 1 or type 2 diabetes)
  • Any reported use of substances which may pose undue personal risk to the participants or introduce bias into the experiment
  • Lifestyle not conforming to standard sleep-wake cycle (e.g. shift worker)
  • Any reported recent (<6 months) change in body mass (± 3%)

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

  • Primary Purpose: Basic Science
  • Allocation: Randomized
  • Interventional Model: Crossover Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm

Participant Group / Arm

A group or subgroup of participants in a clinical trial that receives a specific intervention/treatment, or no intervention, according to the trial's protocol.
Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.
Active Comparator: CONTROL
Diet consisting of 50% carbohydrate (20% sugar), 15% protein, 35% fat
Other: Diet
Macronutrient composition (specifically type and/or amount of carbohydrate) is manipulated
Experimental: LOW SUG
Diet consisting of 50% carbohydrate (<5% sugar), 15% protein, 35% fat
Other: Diet
Macronutrient composition (specifically type and/or amount of carbohydrate) is manipulated
Experimental: LOW CHO
Diet consisting of <8% carbohydrate (<5% sugar), 15% protein, >77% fat
Other: Diet
Macronutrient composition (specifically type and/or amount of carbohydrate) is manipulated

What is the study measuring?

Primary Outcome Measures

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Measure Description
Time Frame
24-hour physical activity energy expenditure (kcal/day)
Time Frame: 24 hours
24-hour physical activity energy expenditure (kcal/day)
24 hours

Secondary Outcome Measures

Secondary Outcome Measures

In a clinical study's protocol, a planned outcome measure that is not as important as the primary outcome measure for evaluating the effect of an intervention but is still of interest. Most clinical studies have more than one secondary outcome measure.
Outcome Measure
Measure Description
Time Frame
24-hour energy intake (kcal/day)
Time Frame: 24 hours
24-hour energy intake (kcal/day)
24 hours
Fasting glucose concentrations
Time Frame: 24 hours
Fasting glucose concentrations in serum samples
24 hours
Postprandial glucose concentrations
Time Frame: 24 hours
Postprandial glucose concentrations in serum samples
24 hours
Fasting insulin concentrations
Time Frame: 24 hours
Fasting insulin concentrations in serum samples
24 hours
Postprandial insulin concentrations
Time Frame: 24 hours
Postprandial insulin concentrations in serum samples
24 hours
Fasting triglyceride concentrations
Time Frame: 24 hours
Fasting and postprandial triglyceride concentrations determined in plasma samples
24 hours
Postprandial triglyceride concentrations
Time Frame: 24 hours
Postprandial triglyceride concentrations in serum samples
24 hours
Fasting non-esterified fatty acid concentrations
Time Frame: 24 hours
Fasting non-esterified fatty acid concentrations in serum samples
24 hours
Postprandial non-esterified fatty acid concentrations
Time Frame: 24 hours
Postprandial non-esterified fatty acid concentrations in serum samples
24 hours
Fasting beta-hydroxybutyrate concentrations
Time Frame: 24 hours
Fasting beta-hydroxybutyrate concentrations in serum samples
24 hours
Postprandial beta-hydroxybutyrate concentrations
Time Frame: 24 hours
Postprandial beta-hydroxybutyrate concentrations in serum samples
24 hours
Subjective appetite
Time Frame: 24 hours
Measured by 0-100 mm visual analogue scale
24 hours
Food preference ratings
Time Frame: 24 hours
Food preference ratings determined by bespoke computer software
24 hours
Resting substrate oxidation
Time Frame: 24 hours
Resting substrate oxidation determined by indirect calorimetry
24 hours
Postprandial substrate oxidation
Time Frame: 24 hours
Postprandial substrate oxidation determined by indirect calorimetry
24 hours
Palatability
Time Frame: 24 hours
Measured by 0-100 mm visual analogue scale
24 hours
Fasting cholesterol, HDL, and LDL concentrations
Time Frame: 24 hours
Fasting cholesterol, HDL, and LDL concentrations in serum samples
24 hours
Postprandial cholesterol, HDL, and LDL concentrations
Time Frame: 24 hours
Postprandial cholesterol, HDL, and LDL concentrations in serum samples
24 hours
Fasting leptin concentrations
Time Frame: 24 hours
Fasting leptin concentrations in serum samples
24 hours
Postprandial leptin concentrations
Time Frame: 24 hours
Postprandial leptin concentrations in serum samples
24 hours
Macronutrient intake
Time Frame: 24 hours
Macronutrient intake across 24-h
24 hours
Fasting FGF21 concentrations
Time Frame: 24 hours
Fasting FGF21 concentrations in serum samples
24 hours
Postprandial FGF21 concentrations
Time Frame: 24 hours
Postprandial FGF21 concentrations in serum samples
24 hours
Eating rate
Time Frame: 24 hours
Time taken to eat test meals
24 hours
Body mass
Time Frame: 24 hours
Body mass
24 hours
Waist and hip circumference
Time Frame: 24 hours
Waist and hip circumference, waist:hip ratio
24 hours
Fasting haematology profile
Time Frame: 24 hours
Fasting haematology profile including WBC, RBC, HGB, haematocrit, platelet count
24 hours

Collaborators and Investigators

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

Sponsor

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
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

Helpful Links

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)

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
December 4, 2017

Primary Completion (Actual)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
May 21, 2021

Study Completion (Actual)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
May 21, 2021

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
April 9, 2018

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
April 25, 2018

First Posted (Actual)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
April 26, 2018

Study Record Updates

Last Update Posted (Actual)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
June 18, 2021

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
June 16, 2021

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
June 1, 2021

More Information

Terms related to this study

Keywords

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant numbers.
  • EP 17/18 87

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

UNDECIDED

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

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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