Carbohydrate Intake and Gut Hormone Release During Exercise

Sponsor

Imperial College London (Other)

Overall Status

Completed

CT.gov ID

NCT04019418

Collaborator

(none)

Enrollment

Location

Arms

11.7

Actual Duration (Months)

Patients Per Site Per Month

Study Details

Study Description

Brief Summary

It is well known that following a single session of moderate-to-high intensity exercise individuals experience a temporary suppression of hunger and a delay in the commencement of eating. This effect is believed to be due to changes in blood concentrations of specific hormones released from the gut that influence appetite.

Individuals undertaking physical activity often consume foods immediately before exercise in order to improve their performance. However, it is currently unknown whether this eating practice influences the gut hormone response to exercise as well as how hungry an individual feels post-exercise.

Therefore, the aim of this study is to investigate the effect of consuming a sugary (carbohydrate) drink immediately before starting an exercise session on the concentration of these gut hormones as well as the amount of food eaten in the hours following exercise completion.

Condition or Disease	Intervention/Treatment	Phase
Obesity	Dietary Supplement: Maltodextrin (carbohydrate) Other: Exercise Other: Rest Other: Water	N/A

Detailed Description

It is well established that following an acute bout of moderate-to-high intensity exercise individuals experience a transient suppression of hunger and a delay in the commencement of eating - a phenomenon referred to as exercise-induced anorexia. Acute exercise modulates the concentrations of gut hormones known to influence satiety, including the anorexigenic hormones glucagon-like peptide 1 (GLP-1) and peptide tyrosine tyrosine (PYY), as well as the acylated form of the orexigenic hormone ghrelin. These alterations in gut hormone concentrations have consequently been hypothesised to play a key role in exercise-induced anorexia.

Despite suppressing hunger and delaying eating, acute exercise does not appear to alter short-term energy intake in the immediate hours following exercise completion. The absence of a compensatory response therefore creates an energy deficit capable of inducing weight loss. Strategies that augment the gut hormone response to acute exercise may thus increase the potency of exercise as a weight-loss tool.

Research investigating the effect of exercise on appetite has frequently utilised participants in a fasting state. Undertaking exercise in this physiological condition contradicts current practices, as athletes often consume a carbohydrate source immediately prior to exercise in an attempt to maximise performance. It is currently unknown as to whether the consumption of carbohydrate during this period may further enhance the gut hormone response to exercise, and thus research into a potential additive effect is warranted.

High-intensity exercise increases sympathetic nervous system activity and catecholamine release. Catecholamine concentrations are negatively correlated with acylated ghrelin concentrations and may directly stimulate GLP-1 and PYY release via activation of β-receptors located on L-cells. The decrease in gastric emptying rate that is observed during high-intensity exercise is also attributed to this increase in sympathetic activity. Consequently, an increase in sympathetic nervous system activity has been postulated as a key mechanism underlying exercise-induced changes in gut hormone concentrations. However, to our knowledge, no study has directly measured the relationship between sympathetic nervous system activity and anorexigenic gut hormone release during exercise.

Therefore, the aim of this study is to examine any potential additive effects of carbohydrate ingestion immediately prior to exercise on gut hormone release and post-exercise appetite suppression. Furthermore, this study will look to investigate the mechanisms underlying changes in gut hormone concentrations experienced during exercise.

Study Design

Study Type:

Interventional

Actual Enrollment :

12 participants

Allocation:

Randomized

Intervention Model:

Crossover Assignment

Intervention Model Description:

Participants perform all four trials in a randomized orderParticipants perform all four trials in a randomized order

Masking:

Double (Participant, Investigator)

Masking Description:

Participants and investigators will be masked to the contents of the beverage. They will not be masked to whether it is a resting or exercise condition as this is not possible.

Primary Purpose:

Basic Science

Official Title:

Carbohydrate Intake and Gut Hormone Release During Exercise

Actual Study Start Date :

Feb 21, 2019

Actual Primary Completion Date :

Feb 12, 2020

Actual Study Completion Date :

Feb 12, 2020

Arms and Interventions

Arm	Intervention/Treatment
Placebo Comparator: No Carbohydrate Drink + Rest Participants will consume the no carbohydrate drink (300ml water) followed by a rest session	Other: Rest 30 minutes laying on a bed Other: Water A drink containing 300ml of water
Active Comparator: No Carbohydrate Drink + Exercise Participants will consume the no carbohydrate drink (300ml water) followed by an exercise session (75% VO2 max on a cycle ergometer)	Other: Exercise 30 minutes on a cycle ergometer working at 75% VO2 max Other: Water A drink containing 300ml of water
Active Comparator: Carbohydrate Drink + Rest Participants will consume the carbohydrate drink (300ml water + 75g maltodextrin) followed by a rest session	Dietary Supplement: Maltodextrin (carbohydrate) A drink containing 300ml of water and 75g of maltodextrin Other: Rest 30 minutes laying on a bed
Experimental: Carbohydrate Drink + Exercise Participants will consume the carbohydrate drink (300ml water + 75g maltodextrin) followed by an exercise session (75% VO2 max on a cycle ergometer)	Dietary Supplement: Maltodextrin (carbohydrate) A drink containing 300ml of water and 75g of maltodextrin Other: Exercise 30 minutes on a cycle ergometer working at 75% VO2 max

Outcome Measures

Primary Outcome Measures

Changes in GLP-1 concentration [During the study visit, 165 minutes]
Changes in GLP-1 concentration between exercise and resting conditions, and between carbohydrate and control conditions
Changes in PYY concentration [During the study visit, 165 minutes]
Changes in PYY concentration between exercise and resting conditions, and between carbohydrate and control conditions
Changes in acylated ghrelin concentration [During the study visit, 165 minutes]
Changes in acylated ghrelin concentration between exercise and resting conditions, and between carbohydrate and control conditions

Secondary Outcome Measures

Changes in energy intake [During the study visit, 165 minutes]
Differences in energy intake at an ad libitum meal between exercise and resting conditions, and between carbohydrate and control conditions
Changes in Energy expenditure [During the study visit, 165 minutes]
Differences in energy expenditure between exercise and resting conditions, and between carbohydrate and control conditions.
Changes in energy balance [During the study visit, 165 minutes]
Differences in energy balance between exercise and resting conditions, and between carbohydrate and control conditions.
Glucose homeostasis [During the study visit, 165 minutes]
Changes in glucose homeostasis between exercise and resting conditions, and between carbohydrate and control conditions.
Changes in subjective nausea [During the study visit, 165 minutes]
Changes in subjective feelings of nausea as measured by visual analogue scales between exercise and resting conditions, and between carbohydrate and control conditions. Visual analogue scales will range from 0 mm to 100 mm with a higher score indicating a higher degree of nausea.
Changes in subjective appetite [During the study visit, 165 minutes]
Changes in subjective feelings of appetite as measured by visual analogue scales between exercise and resting conditions, and between carbohydrate and control conditions. Visual analogue scales will range from 0 mm to 100 mm with a higher score indicating a higher degree of fullness.

Eligibility Criteria

Criteria

Ages Eligible for Study:

18 Years to 40 Years

Sexes Eligible for Study:

Male

Accepts Healthy Volunteers:

Yes

Inclusion Criteria:

Male
Age between 18-40 years (inclusive)
Body mass index (BMI) of 18-30 kg/m2
Willingness and ability to give written informed consent and willingness and ability to understand, to participate and to comply with the study requirements

Exclusion Criteria:

Abnormal ECG
Screening blood results outside of normal reference values
Current smokers
Current or history of substance abuse and/or excess alcohol intake
Diabetes
Cardiovascular disease
Cancer
Gastrointestinal disease e.g. inflammatory bowel disease or irritable bowel syndrome
Kidney disease
Liver disease
Pancreatitis
Started new medication within the last 3 months likely to interfere with energy metabolism, appetite regulation and hormonal balance, including: anti-inflammatory drugs or steroids, antibiotics, androgens, phenytoin, erythromycin or thyroid hormones.
Participation in a research study in the 12 week period prior to entering this study.
Any blood donation within the 12 week period prior to entering this study