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Completed

NCT Number: NCT06853249

Influence of Food Texture on Appetite Control, Gastric Emptying, and Energy Expenditure

The aim of the study is to investigate the effect of liquid versus semi-solid meals on the regulation of energy balance in healthy young adults.The main questions it aims to answer are:

* Does a protein-rich liquid meal result in less satiety and therefore higher ad libitum energy intake at the next meal than an isocaloric oatmeal with the same macronutrient ratio? * Is the consumption of a protein-rich liquid meal as a beverage in addition to an ad libitum oatmeal less compensated within the meal and at the next meal and provides thus a higher ad libitum energy intake than an isovolumetric noncaloric soft drink in addition to an ad libitum oatmeal?

Researchers will compare a protein-rich liquid meal to an isocaloric oatmeal with matched macronutrient composition to answer the first question. Researchers will compare a protein-rich liquid meal + oatmeal to a noncaloric softdrink (water with sucralose and flavoring) + oatmeal to answer the second question.

Participants will:

* spend 4 intervention days in a metabolic chamber (whole room indirect calorimeter) * consume pre-definied preloads for breakfast and ad libitum lunch meals on 4 intervention days

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Key information

Conditions

Nutrition Healthy Male and Female Subjects

Age range

18 year–35 year

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

Kiel University, Institute of Human Nutrition

Kiel, Germany

Who can participate

Healthy volunteers accepted: Yes

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

Inclusion criteria

  • healthy males and females
  • Body Mass Index between 19-35 kg/m2
  • low to medium habitual physical activity
  • women with regular menstrual cycle (during intervention in follicular phase)

Exclusion criteria

  • smoking (cigarettes + cannabis)
  • chronic illnesses
  • regular intake of medication
  • Anemia and/or iron deficiency
  • food allergies / intolerances
  • vegans
  • regular high physical activity (exercise >1 hour/d)
  • current weight loss diet / weight loss of >5 kg in the last 3 months
  • restraint eaters (according to the German version of the 'Three-Factor-Eating-Questionnaire', Stunkard und Messick (1985))
  • active participation in another trial
  • pregnant / lactating women
  • persons incapable of giving informed legal consent

Treatment and study plan

liquid meal

Other

An isocaloric amount (500 kcal) of a commercially available liquid meal with a matched macronutrient composition is consumed. After 5 hours, lunch is eaten ad libitum.

semi-solid meal

Other

An isocaloric amount (500 kcal) of a commercially available semi-solid oatmeal with a matched macronutrient composition is consumed. After 5 hours, lunch is eaten ad libitum.

caloric drink + semi-solid meal

Other

A predefined amount of a caloric drink (= liquid meal) together with an ad libitum amount of a semi-solid meal is consumed. After 5 hours, lunch is eaten ad libitum.

non-caloric drink + semi-solid meal

Other

A predefined amount of a non-caloric drink (= water, sucralose, flavor) together with an ad libitum amount of a semi-solid meal is consumed. After 5 hours, lunch is eaten ad libitum.

Primary outcomes

  1. ad libitum energy intake

    Time frame: for 9 hours after the consumption of the preloads

    measured during preload and lunch [kcal] following the preload in both arms

Secondary outcomes

  1. gastric emptying

    Time frame: for 4 hours after the consumption of the isocaloric preloads

    gastric half-emptying time [min] determined with 13C-sodium acetate breath test, only assessed during arm "isocaloric preload"

  2. eating rate at lunch

    Time frame: at 5 hours after consumption of the preload

    assessed during ad libitum lunch [g/min] following the preload in both arms

  3. number of chews per bite at lunch

    Time frame: at 5 hours after consumption of the preload

    assessed during ad libitum lunch [number] following the preload in both arms

  4. serum ghrelin concentrations

    Time frame: for 3 hours after consumption of the isocaloric preloads

    area under the serum ghrelin concentration curve over 3 hours

  5. serum peptide-YY (PYY) concentrations

    Time frame: for 3 hours after consumption of the isocaloric preloads

    area under the serum PYY concentration curve over 3 hours

  6. serum Glucagon-like Peptide 1 (GLP-1) concentrations

    Time frame: for 3 hours after consumption of the isocaloric preloads

    area under the serum GLP-1 concentration curve over 3 hours

  7. energy expenditure

    Time frame: measured for 9.5 hours

    Measured as kcal for 9.5 hours in a whole room indirect calorimeter (WRIC), including the consumption of the preload and the ad libitum lunch.

  8. macronutrient oxidation

    Time frame: measured for 9.5 hours

    Measured as respiratory exchange ratio (RER) for 9.5 hours in a whole room indirect calorimeter (WRIC), including the consumption of the preload and the ad libitum lunch.

Sponsors and collaborators

Lead sponsor

University of Kiel

Other

Registry information

Important dates

Study start
2025
Primary completion
2025
Study completion
2026
First posted
Feb 28, 2025
Registry last updated
May 5, 2026

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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