Clinical trial NCT03574987: Dietary Carbohydrate Manipulation and Energy Balance: RCT
Official title: The Effect of Dietary Carbohydrate Manipulation on All Major Aspects of Energy Balance: A 12-week Randomised Controlled Trial
Study type: INTERVENTIONAL
Overall status: COMPLETED
Phase: NA
Conditions: Physical Activity
Diet Modification
Keywords: Physical Activity
Nutrition
Carbohydrates
Sugar
Energy Balance
Lead sponsor: University of Bath
Sponsor class: OTHER
First posted: 2018-07-02
Enrollment: 60
Sex: ALL
Minimum age (years): 18
Maximum age (years): 65
Standard ages: ADULT
OLDER_ADULT
Accepts healthy volunteers: yes
Allocation: RANDOMIZED
Intervention model: PARALLEL
Intervention model description: Randomised controlled trial with 3 arms. One arm is a typical diet (50% CHO, 20% SUG), one arm is low sugar (50% CHO, \<5% SUG), one arm is low carbohydrate (\<8% CHO, \<5% SUG). Stratified by sex and physical activity level (PAL).
Primary purpose: BASIC_SCIENCE

Brief summary: This study will investigate how dietary sugar and carbohydrates influence metabolism and health across a 12-week period, with a focus on physical activity. One third of participants will eat a diet with typical amounts of sugar and carbohydrate, one third of participants will eat a diet with sugar intake restricted, and the final third of participants will eat a diet where both sugar and total carbohydrates are restricted and replaced with fat.

Detailed description: 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 is only one half of the energy balance equation (energy in vs energy out). Without considering energy expenditure, it is impossible to fully understand the effects of sugar on health. Removing dietary sugar or carbohydrates from the diet may influence energy balance through mechanisms other than energy intake - for example by reducing levels of physical activity.

Understanding dietary regulators of energy balance is more important than ever because diseases like obesity are a consequence of energy surplus (i.e. energy in \> energy out). No studies have investigated a causal role of dietary sugar or carbohydrate on energy balance. The proposed research will seek to understand the responses to manipulating dietary carbohydrate and sugar content on energy balance and health. This research will enable the public to make informed dietary choices about carbohydrate and sugar consumption.

To achieve this, healthy non-obese adults, aged 18-65 years will be recruited to take part in an intervention study with measures of energy intake, energy expenditure, metabolic health, gut microbiota, and appetite. All laboratory trials will take place at the University of Bath. Participants will be randomised to consume one of three diets for a period of 12 weeks, with laboratory visits at baseline, at week 4, and at week 12:

1. CONTROL (moderate sugar) - 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, replacing carbohydrate energy with fat

Eligibility criteria: 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/contraceptive use
* No anticipated changes in physical activity during the first 4 weeks of the study (e.g. holidays or training programmes)

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%)
* Use of antibiotic medication in the last 3 months
* Use of prebiotic or probiotic products in the last month

Primary outcomes:
measure: Physical Activity Energy Expenditure (kJ/Day or kcal/Day)
timeFrame: 7 days (across 12 weeks) - Primary outcome at week 4
Secondary outcomes:
measure: Time Spent in Different Physical Activity Intensities (MET Categories) (Minutes)
timeFrame: 7 days (across 12 weeks)
measure: Energy Expended in Different Physical Activity Intensities (MET Categories) (kJ or kcal)
timeFrame: 7 days (across 12 weeks)
measure: Energy Intake and Dietary Macronutrient Composition
timeFrame: 12 weeks
measure: Body Mass
timeFrame: 12 weeks
measure: Bone Mineral Density
timeFrame: 12 weeks
measure: Bone Mineral Content
timeFrame: 12 weeks
measure: Fat Mass
timeFrame: 12 weeks
measure: Fat-free Mass
timeFrame: 12 weeks
measure: Android Fat Mass
timeFrame: 12 weeks
measure: Gynoid Fat Mass
timeFrame: 12 weeks
measure: Resting Metabolic Rate
timeFrame: 12 weeks
measure: Substrate Oxidation
timeFrame: 12 weeks
measure: Waist and Hip Circumference
timeFrame: 12 weeks
measure: Step Count
timeFrame: 12 weeks
measure: Fasting Metabolite/Hormone Profile
timeFrame: 12 weeks
measure: Postprandial Metabolite/Hormone Profile
timeFrame: 4 hours (across 12 weeks)
measure: Blood Pressure
timeFrame: 12 weeks
measure: Food Preference Ratings
timeFrame: 12 weeks
measure: Subjective Appetite and Mood Ratings
timeFrame: 12 weeks
measure: Interstitial Glucose Concentrations
timeFrame: 14 days (across 12 weeks)
measure: Adipose Tissue Gene Expression
timeFrame: 12 weeks
measure: Adipose Tissue Protein Expression
timeFrame: 12 weeks
measure: Muscle Tissue Gene Expression
timeFrame: 12 weeks
measure: Muscle Tissue Protein Expression
timeFrame: 12 weeks
measure: Muscle Glycogen Concentrations
timeFrame: 12 weeks
measure: Gut Microbiome Characterisation
timeFrame: 12 weeks
measure: Urinary Acetoacetate Concentrations
timeFrame: 12 weeks
measure: Urine Urea Nitrogen Excretion
timeFrame: 12 weeks
Other outcomes:
Locations:
city: Bath
country: United Kingdom
facility: Department for Health, University of Bath
Study officials:
References:
citation: Smith HA, Gonzalez JT, Thompson D, Betts JA. Dietary carbohydrates, components of energy balance, and associated health outcomes. Nutr Rev. 2017 Oct 1;75(10):783-797. doi: 10.1093/nutrit/nux045.
citation: Betts JA, Richardson JD, Chowdhury EA, Holman GD, Tsintzas K, Thompson D. The causal role of breakfast in energy balance and health: a randomized controlled trial in lean adults. Am J Clin Nutr. 2014 Aug;100(2):539-47. doi: 10.3945/ajcn.114.083402. Epub 2014 Jun 4.
citation: Erickson J, Sadeghirad B, Lytvyn L, Slavin J, Johnston BC. The Scientific Basis of Guideline Recommendations on Sugar Intake: A Systematic Review. Ann Intern Med. 2017 Feb 21;166(4):257-267. doi: 10.7326/M16-2020. Epub 2016 Dec 20.
citation: Bergwall S, Johansson A, Sonestedt E, Acosta S. High versus low-added sugar consumption for the primary prevention of cardiovascular disease. Cochrane Database Syst Rev. 2022 Jan 5;1(1):CD013320. doi: 10.1002/14651858.CD013320.pub2.