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NCT Number: NCT07104461

Advanced Protein-based Program for Effective Treatment of Appetite Regulation and Obesity

INTRODUCTION: Obesity is a global epidemic, with over 2.5 billion adults being classified as overweight and 890 million of these classified as obese. Overweight and obesity are the 5th cause of mortality globally, with an estimated 2.8 million related deaths among adults. The rising prevalence of obesity in adults is leading to a rise in the prevalence of type 2 diabetes, with an estimated 462 million individuals affected globally. At present, the most effective non-surgical obesity treatments offered by the National Health Service (NHS) are the subcutaneously administered GLP-1 receptor agonists. However, they may present potentially serious side effects following short-term use, and there are still uncertainties around long-term use side effects. Therefore, a dietary approach to weight loss or maintenance seems preferable.

Increasing protein intake is a commonly applied nutritional approach to appetite regulation. The increase in protein intake is often achieved by supplementation, using proteins isolated from dairy, such as whey and casein. However, with more individuals following plant-based diets over recent years, the interest in plant-based protein supplements has increased. While dairy-based proteins are well-characterised, the appetite regulatory characteristics of plant-based proteins have not yet been fully elucidated.

The main aim of this study is to investigate the effects of protein-enriched food items on appetite regulation compared to a standard carbohydrate-rich meal. Furthermore, this study will investigate whether there are any differences in appetite-related hormonal responses to a plant protein-containing meal replacement shake (containing rice and pea protein) or a potato protein-enriched standard carbohydrate-based meal compared to a whey protein-enriched standard carbohydrate-based meal.

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Key information

Conditions

Appetite and General Nutritional Disorders Glucose Metabolism Disorders Hyperinsulinism Insulin Resistance Metabolic Diseases Nutritional and Metabolic Diseases

Age range

18 year–50 year

Sex eligibility

Male

Study type

Interventional

Phase

Not applicable

Primary location

Centre for Nutraceuticals School of Life Sciences, University of Westminster

London, W1W 6UW, United Kingdom

About this study

Intervention study with four treatment groups in a randomised, single-blind, quadruple crossover design.

Healthy male participants (between the ages of 18 to 50 years) will receive four different isocaloric intervention meals with the same mass, on separate visit days, following a minimum of 8 hours overnight fast. The four meals will contain oat porridge prepared with coconut milk as a control, oat porridge prepared with coconut milk with added whey or potato protein isolates, and a complete meal replacement shake containing plant-based pea and rice proteins. The intervention meals will be followed by a standardised pasta-based ready meal after the 3-hour observation period. All participants will observe at least a two-day washout period between the differing treatments.

Biological samples (blood) will be collected at various times during the visit. Blood samples will be collected at baseline 0 min prior (T0), then at 30 min (T30), 60 min (T60), 120 min (T120) and 180 min (T180) after the intervention meal consumption.

In addition, pertinent questionnaires, Visual Analogue Scale [VAS] for assessing satiety and VAS for assessing intervention meals' perception and palatability will be collected. VAS for the assessment of satiety will be collected at T0, T30, T60, T120 and T180 and VAS assessing the perception and palatability of the intervention meals will be collected immediately following meal consumption.

Who can participate

Healthy volunteers accepted: Yes

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

Inclusion criteria

  • Males (18-50 years of age)
  • Lean and Overweight subjects (BMI 18.5 - 30 kg/m2)
  • Sedentary and physically active subjects
  • Healthy subjects

Exclusion criteria

  • Female
  • <18, >50 years
  • Dieting
  • Consumption of >14 units of alcohol/week
  • Allergies to test foods/drinks
  • Illnesses or on medication (with a possible effect on taste and/or appetite)
  • Devices such as pacemakers
  • Smokers
  • Gastrointestinal disorders
  • Eating disorders

Treatment and study plan

Oat porridge

Other

Oat flakes, 81g (equivalent to 9 g of protein), were presented to participants in the form of porridge, prepared with 500 mL coconut milk (equivalent to 0.5 g of protein) and 10 g of zero calorie sugar free syrup.

The total energy content was equivalent to 400 Kcal.

Participants were instructed to consume the entire meal presented to them in 15 minutes on an empty stomach when attending the study.

Whey protein isolate

Dietary Supplement

Whey protein isolate, 38g (equivalent to 34.2 g of protein), was presented to participants in the form of a porridge.

Other ingredients in the whey protein enriched porridge:

  • Oat flakes 54 g (equivalent to 6 g of protein)
  • Coconut milk 300 mL (equivalent to 0.3 g of protein)
  • Water 150 mL
  • Zero calorie sugar free syrup 10 g

The total energy content was equivalent to 401.74 Kcal.

Participants were instructed to consume the entire meal presented to them in 15 minutes on an empty stomach when attending the study

Potato protein isolate

Dietary Supplement

Potato protein isolate, 38g (equivalent to 34.39 g of protein), was presented to participants in the form of a porridge.

Other ingredients in the potato protein enriched porridge:

  • Oat flakes 54 g (equivalent to 6 g of protein)
  • Coconut milk 300 mL (equivalent to 0.3 g of protein)
  • Water 150 mL
  • Zero calorie sugar free syrup 10 g

The total energy content equiv. 401.36 Kcal.

Participants were instructed to consume the entire meal presented to them in 15 minutes on an empty stomach when attending the study.

Meal replacement shake

Dietary Supplement

A meal replacement, 90 g (equivalent to 40 g of total protein), was presented to participants in the form of a shake.

Other ingredients in the meal replacement shake:

  • Water 500 mL

The total energy was equivalent to 400 Kcal

Participants were instructed to consume the entire meal replacement shake presented to them in 15 minutes on an empty stomach when attending the study.

Primary outcomes

  1. To assess the acute effects of oat porridge, whey protein isolate, potato protein isolate and meal replacement shake on glucose levels (T30)

    Time frame: Glucose measured 30 minutes post meal consumption

    Glucose (mmol/L)

  2. To assess the acute effects of oat porridge, whey protein isolate, potato protein isolate, and meal replacement shake on glucose levels (T60)

    Time frame: Glucose measured 60 minutes post meal consumption

    Glucose (mmol/L)

  3. To assess the acute effects of oat porridge, whey protein isolate, potato protein isolate, and meal replacement shake on glucose levels (T120)

    Time frame: Glucose measured 120 minutes post meal consumption

    Glucose (mmol/L)

  4. To assess the acute effects of oat porridge, whey protein isolate, potato protein isolate, and meal replacement shake on glucose levels (T180)

    Time frame: Glucose measured 180 minutes post meal consumption

    Glucose (mmol/L)

  5. To assess the acute effects of oat porridge, whey protein isolate, potato protein isolate, and meal replacement shake on insulin levels (T30)

    Time frame: Insulin measured 30 minutes post meal consumption

    Insulin (pmol/L)

  6. To assess the acute effects of oat porridge, whey protein isolate, potato protein isolate, and meal replacement shake on insulin levels (T60)

    Time frame: Insulin measured 160 minutes post meal consumption

    Insulin (pmol/L)

  7. To assess the acute effects of oat porridge, whey protein isolate, potato protein isolate, and meal replacement shake on insulin levels (T120)

    Time frame: Insulin measured 120 minutes post meal consumption

    Insulin (pmol/L)

  8. To assess the acute effects of oat porridge, whey protein isolate, potato protein isolate, and meal replacement shake on insulin levels (T180)

    Time frame: Insulin measured 180 minutes post meal consumption

    Insulin (pmol/L)

  9. To assess the acute effects of oat porridge, whey protein isolate, potato protein isolate, and meal replacement shake on glucagon-like peptide 1 levels (T30)

    Time frame: Glucagon-like peptide 1 measured 30 minutes post meal consumption

    Glucagon-like peptide 1 (pmol/L)

  10. To assess the acute effects of oat porridge, whey protein isolate, potato protein isolate, and meal replacement shake on glucagon-like peptide 1 levels (T60)

    Time frame: Glucagon-like peptide 1 measured 60 minutes post meal consumption

    Glucagon-like peptide 1 (pmol/L)

  11. To assess the acute effects of oat porridge, whey protein isolate, potato protein isolate, and meal replacement shake on glucagon-like peptide 1 levels (T120)

    Time frame: Glucagon-like peptide 1 measured 120 minutes post meal consumption

    Glucagon-like peptide 1 (pmol/L)

  12. To assess the acute effects of oat porridge, whey protein isolate, potato protein isolate, and meal replacement shake on glucagon-like peptide 1 levels (T180)

    Time frame: Glucagon-like peptide 1 measured 180 minutes post meal consumption

    Glucagon-like peptide 1 (pmol/L)

  13. To assess the acute effects of oat porridge, whey protein isolate, potato protein isolate, and meal replacement shake on gastric inhibitory polypeptide (T30)

    Time frame: Gastric inhibitory polypeptide measured 30 minutes post meal consumption

    Glucagon-like peptide 1 (pmol/L)

  14. To assess the acute effects of oat porridge, whey protein isolate, potato protein isolate, and meal replacement shake on gastric inhibitory polypeptide (T60)

    Time frame: Gastric inhibitory polypeptide measured 60 minutes post meal consumption

    Glucagon-like peptide 1 (pmol/L)

  15. To assess the acute effects of oat porridge, whey protein isolate, potato protein isolate, and meal replacement shake on gastric inhibitory polypeptide (T120)

    Time frame: Gastric inhibitory polypeptide measured 120 minutes post meal consumption

    Glucagon-like peptide 1 (pmol/L)

  16. To assess the acute effects of oat porridge, whey protein isolate, potato protein isolate, and meal replacement shake on gastric inhibitory polypeptide (T180)

    Time frame: Gastric inhibitory polypeptide measured 180 minutes post meal consumption

    Glucagon-like peptide 1 (pmol/L)

  17. To assess the acute effects of oat porridge, whey protein isolate, potato protein isolate, and meal replacement shake on peptide tyrosine tyrosine levels (T30)

    Time frame: Peptide tyrosine tyrosine measured 30 minutes post meal consumption

    Peptide tyrosine tyrosine (pmol/L)

  18. To assess the acute effects of oat porridge, whey protein isolate, potato protein isolate, and meal replacement shake on peptide tyrosine tyrosine levels (T60) Markers: peptide tyrosine tyrosine (pmol/L)

    Time frame: Peptide tyrosine tyrosine measured 60 minutes post meal consumption

    Peptide tyrosine tyrosine (pmol/L)

  19. To assess the acute effects of oat porridge, whey protein isolate, potato protein isolate, and meal replacement shake on peptide tyrosine tyrosine levels (T120)

    Time frame: Peptide tyrosine tyrosine measured 120 minutes post meal consumption

    Peptide tyrosine tyrosine (pmol/L)

  20. To assess the acute effects of oat porridge, whey protein isolate, potato protein isolate, and meal replacement shake on peptide tyrosine tyrosine levels (T180)

    Time frame: Peptide tyrosine tyrosine measured 180 minutes post meal consumption

    Peptide tyrosine tyrosine (pmol/L)

  21. To assess the acute effects of oat porridge, whey protein isolate, potato protein isolate, and meal replacement shake on ghrelin levels (T30)

    Time frame: Ghrelin measured 30 minutes post meal consumption

    Ghrelin (pmol/L)

  22. To assess the acute effects of oat porridge, whey protein isolate, potato protein isolate, and meal replacement shake on ghrelin levels (T60)

    Time frame: Ghrelin measured 60 minutes post meal consumption

    Ghrelin (pmol/L)

  23. To assess the acute effects of oat porridge, whey protein isolate, potato protein isolate, and meal replacement shake on ghrelin levels (T120)

    Time frame: Ghrelin measured 120 minutes post meal consumption

    Ghrelin (pmol/L)

  24. To assess the acute effects of oat porridge, whey protein isolate, potato protein isolate, and meal replacement shake on ghrelin levels (T180)

    Time frame: Ghrelin measured 180 minutes post meal consumption

    Ghrelin (pmol/L)

  25. To assess the acute effects of oat porridge, whey protein isolate, potato protein isolate, and meal replacement shake on appetite (T30)

    Time frame: Visual Analogue Scale for Appetite (VAS-A) collected 30 minutes after meal consumption

    Subjective analysis including: Visual Analogue Scale for Appetite (VAS-A). Scores range from 0 to 100 (the higher the score, the greater the level of appetite)

  26. To assess the acute effects of oat porridge, whey protein isolate, potato protein isolate, and meal replacement shake on appetite (T60)

    Time frame: Visual Analogue Scale for Appetite (VAS-A) collected 60 minutes after meal consumption

    Subjective analysis including: Visual Analogue Scale for Appetite (VAS-A). Scores range from 0 to 100 (the higher the score, the greater the level of appetite)

  27. To assess the acute effects of oat porridge, whey protein isolate, potato protein isolate, and meal replacement shake on appetite (T120)

    Time frame: Visual Analogue Scale for Appetite (VAS-A) collected 120 minutes after meal consumption

    Subjective analysis including: Visual Analogue Scale for Appetite (VAS-A). Scores range from 0 to 100 (the higher the score, the greater the level of appetite)

  28. To assess the acute effects of oat porridge, whey protein isolate, potato protein isolate, and meal replacement shake on appetite (T180)

    Time frame: Visual Analogue Scale for Appetite (VAS-A) collected 180 minutes after meal consumption

    Subjective analysis including: Visual Analogue Scale for Appetite (VAS-A). Scores range from 0 to 100 (the higher the score, the greater the level of appetite)

Secondary outcomes

  1. To assess the perception of oat porridge, whey protein isolate, potato protein isolate, and meal replacement shake. Subjective analysis including Visual Analogue Scale for Perception and Palatability (VAS-P).

    Time frame: VAS for Perception and Palatability collected immediately after meal consumption

    Scores range from 0 to 100 (the higher the score, the lower the palatability)

  2. To assess the effects of oat porridge, whey protein isolate, potato protein isolate, and meal replacement shake on food intake ad libitum, 3 hours after the intervention meal consumption.

    Time frame: Ad libitum food intake was assessed 3 hours post breakfast intervention meal consumption

    Consecutive meal intake was assessed by measuring the weight in grams and calculating the energy content in Kcal of the food consumed.

Sponsors and collaborators

Lead sponsor

University of Westminster

Other

Registry information

Official study title

A Single-blind Randomised Study to Test the Effects of Protein-enriched Breakfast Meals With Varying Protein Sources Compared to a Standard Meal on the Regulation of Appetite and Satiety in Healthy Human Volunteers

Acronym: APPETITE

Important dates

Study start
2023
Primary completion
2024
Study completion
2024
First posted
Aug 5, 2025
Registry last updated
Aug 21, 2025

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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