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Completed

NCT Number: NCT03922685

Effects of Diet and Exercise on Circadian Glycemia

Specific aims of the study are:

1. to evaluate whether a 24-h exposure to a 25%-carbohydrate diet will reduce postprandial glycemia to the same extent in the evening (19 h) as in the morning (7 h),. and 2. to determine whether one hour of post-meal moderate intensity exercise (at 50% of maximal effort) will further reduce postprandial glycemia.

The outcome measures are: plasma concentrations of glucose, insulin, glucose-dependent-insulinotropic peptide (GIP), leptin, and the ketone body beta-hydroxybutyrate.

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Key information

Conditions

Glucose Intolerance Glucose Metabolism Disorders Hyperglycemia Metabolic Diseases Nutritional and Metabolic Diseases

Age range

50 year–65 year

Sex eligibility

Female

Study type

Interventional

Phase

Not applicable

About this study

The two hypotheses in this study are:

  • A 24-h exposure to a 25%-carbohydrate diet will reduce postprandial glycemia to the same extent in the evening (19 h) as in the morning (7 h), and
  • One hour of moderate-intensity exercise (at 50% of maximal effort) will further reduce postprandial glycemia to the same extent in the evening (19 h) as in the morning (7 h).

Eight postmenopausal subjects (age 58.5 years, BMI 25.6 kg/m2) participated in 4 24-h long crossover trials, two terminating at 7h and the other 2 at 19h. At each circadian time one trial required 60 minutes of moderate-intensity exercise (50% of maximal effort), and the other two involved no exercise.

Three 25%-carbohydrate meals prepared by the Michigan Clinical Research Unit (MCRU) kitchen, were eaten at subjects' home, and the fourth was eaten 20 minutes after subjects' arrival at MCRU at either 19 h or 7 h. Blood was collected from antecubital catheter at 10-minute intervals until 23:20 h or 11:20 h, respectively.Plasma was treated with protease inhibitor to preserve GIP, frozen at -80o C until glucose measurements by glucose oxidase, hormone measurements by chemiluminescence, and ketone measurements by Abbott meter strips.

Exercise intensity was determined before the exercise trials on a treadmill from oxygen consumption (VO2) and carbon dioxide production (VCO2) by subjects walking on a treadmill at 3 mph with the treadmill slope increased by 2% every 3 minutes. Maximal effort was established when respiratory exchange ratio (VCO2/VO2) reached or exceeded 1. The treadmill speed and slope at half maximal effort was used during the one-hour exercise bout which was initiated 40 minutes after the start of the meal.

Who can participate

Healthy volunteers accepted: Yes

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • postmenopausal
  • normal blood glucose
  • no cholesterol medication
  • age between 50 an 65 years
  • overweight but not obese
  • BMI between 25 and 30 kg/m2
  • weight-stable during past 6 months
  • exercise less than 20 minutes three times a week

Exclusion criteria

  • metabolic disease other than hormonally-corrected hypothyroidism
  • musculo-skeletal disability that would preclude exercise
  • smoker
  • do not meet inclusion criteria

Treatment and study plan

Dietary manipulation (25% carbohydrate diet) and behavioral (exercise)

Combination Product

The 25% carbohydrate diet consisted of Pulmocare-vanilla liquid, white roll, butter, and string cheese in proportions to achieve 33% of weigh-maintenance diet containing 25% carbohydrate, 20% protein, and 55% fat. Exercise was walking 1 hour on level treadmill at 50% of maximal effort starting 40 minutes after the beginning of the meal

Dietary manipulation (25% carbohydrate diet) and behavioral (sedentary)

Combination Product

The 25% carbohydrate diet consisted of Pulmocare-vanilla liquid, white roll, butter, and string cheese in proportions to achieve 33% of weigh-maintenance diet containing 25% carbohydrate, 20% protein, and 55% fat. There was no exercise during this trial.

Primary outcomes

  1. Postprandial glucose concentration

    Time frame: Four hours: 19:20 to 23:20 in the evening trials; 7:20 to 11:20 in the morning trials

    The area under the postprandial glucose curve

  2. Postprandial insulin concentration

    Time frame: Four hours: 19:20 to 23:20 in the evening trials; 7:20 to 11:20 in the morning trials

    The area under the postprandial insulin curve

Secondary outcomes

  1. Postprandial glucose-dependent insulinotropic peptide (GIP) concentration

    Time frame: Four hours: 19:20 to 23:20 in the evening trials; 7:20 to 11:20 in the morning trials

    The area under the postprandial GIP curve

  2. Postprandial beta-hydroxybutyrate concentration

    Time frame: Four hours: 19:20 to 23:20 in the evening trials; 7:20 to 11:20 in the morning trials

    The area under the beta-hydroxybutyrate postprandial curve

  3. Postprandial leptin concentration

    Time frame: Four hours: 19:20 to 23:20 in the evening trials; 7:20 to 11:20 in the morning trials

    The area under the leptin postprandial curve

Sponsors and collaborators

Lead sponsor

University of Michigan

Other

Collaborators

  • Northern Michigan University

Registry information

Official study title

Control of Postprandial Glycemia: the Roles of Diet and Exercise

Acronym: GLYCEMIA

Important dates

Study start
2016
Primary completion
2017
Study completion
2019
First posted
Apr 22, 2019
Registry last updated
Apr 22, 2019

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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