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NCT Number: NCT07429136

Plant-based Protein-rich Weight Loss Intervention in 55+ Adults With Obesity

The objective of the 2EAT RCT is to investigate whether a shift towards more plant-based (≥60% with a minimum of 50%) protein intake can be achieved in an energy restricted diet for three and six months in older adults (55+) with obesity.

The 2EAT researchers developed a new dietary counseling plan for six months. This includes four individual consultations, five group meetings and three 24h-recalls. In these six months, participants receive dietary counseling focused on energy restriction (-500 kcal), higher protein intake (aim towards 1.2 g/kg/d, minimum of 0.8 g/kg/d). Participants are randomly allocated either to the more plant-based diet (≥60%) or the more animal-based diet (≥60%). At the start of the intervention, participants are provided with a workbook and recipe book.

Secondary objectives are to assess the effect after three and six months 2EAT dietary treatment on 1) weight loss and 2) skeletal muscle mass. Exploratory objectives are to assess the effect after three and six months 2EAT dietary treatment on 1) physical health outcomes (muscle mass and physical performance), 2) body composition, 3) metabolic blood parameters, 4) vitality and quality of life, 5) nutritional intake, 6) behavioral changes, 7) evaluate the process of the dietary treatment.

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Key information

Conditions

Obesity Body Weight Nutrition Disorders Nutritional and Metabolic Diseases Overnutrition Overweight Pathological Conditions, Signs and Symptoms Signs and Symptoms

Age range

55 year and older

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

Hogeschool van Amsterdam

Amsterdam, South Holland, 1067SM, Netherlands

Location status: Recruiting

Location contact

Wildemast

CONTACT

[email protected]

0641679606

Who can participate

Healthy volunteers accepted: No

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

Inclusion criteria

  • Aged 55 or older
  • Are obese: have a BMI of >30 kg/m2 or BMI >27 kg/m2 and waist circumference >88 cm (women) or >102 cm (men)
  • Living independently (not in a health facility)
  • The willingness that the general practitioner will be notified of study participation
  • Written informed consent
  • Willingness to comply with the protocol
  • Consent of the study physician

Exclusion criteria

  • Inability to understand the Dutch language
  • Cognitive impairment (MMSE <15)
  • Use of total or partial parenteral nutrition (TPN)
  • Alcohol or drug abuse in the opinion of the investigator
  • Current enrolment in a fixed rehabilitation program or other intervention studies
  • Palliative treatment or a life expectancy of ≤ 3 months
  • Following a vegetarian or vegan (100% plant-based) diet
  • Bariatric surgery
  • Active medical treatment interfering with this intervention (e.g. weight loss medication as Ozempic, cancer patients receiving systemic and immune therapy)
  • Physical disabled: unable to meet the general daily exercise guideline for adults
  • Planned a holiday during the intervention period and is unable to attend group- or individual sessions for > 3 weeks

The health conditions below will be assessed by the study physician. When a condition interferes the dietary treatment or if the diet worsens the participants health it counts as exclusion criteria:

  • Diagnosed with unstable coronary heart disease (CHD), decompensated heart failure, uncontrolled hypertension or uncontrolled arrhythmias (e.g. heart failure NYHA >3)
  • Diagnosed degenerative neurocognitive disorders
  • Diagnosed with renal failure
  • COPD GOLD >3

Treatment and study plan

More plant-based protein intake during weight loss

Behavioral

Participants receive dietary counseling for six months focusing on 1) energy restriction (-500 kcal), 2) higher protein intake (aim 1.2 g/kg/d, minimum 0.8 g/kg/d) and according to their assigned diet, either 3) more plant-based protein (≥60%) or more animal-based protein (≥60%).

Primary outcomes

  1. Feasibility of high plant-based protein intake while simultaneously striving for weight loss and increased protein intake

    Time frame: At baseline (week 0), in week 13 (halfway), in week 26 (end), and optional follow-up (week 52)

    Three-day food record (plant protein intake as part of total protein intake; g/day)

Secondary outcomes

  1. Feasibility of a weight loss diet during a more plant-based, higher protein intake

    Time frame: At baseline (week 0), in week 13 (halfway), in week 26 (end), and optional follow-up (week 52)

    Three-day food record on energy (kcal/day)

  2. Feasibility of an increased protein intake during a more plant-based protein, weight loss diet

    Time frame: At baseline (week 0), in week 13 (halfway), in week 26 (end), and optional follow-up (week 52)

    Three-day food record on protein intake (g/day)

  3. Effect of 2EAT dietary treatment on weight loss

    Time frame: At baseline (week 0), in week 13 (halfway), in week 26 (end), and optional follow-up (week 52)

    Body weight in kg (calibrated weighing scales)

  4. Effect of 2EAT dietary treatment on skeletal muscle mass

    Time frame: At baseline (week 0), in week 13 (halfway), in week 26 (end), and optional follow-up (week 52)

    Skeletal muscle mass (appendicular lean soft tissue (ALST) in kg) via a DXA-scan

Other outcomes

  1. Effect of 2EAT dietary treatment on physical performance

    Time frame: At baseline (week 0), in week 13 (halfway), in week 26 (end), and optional follow-up (week 52)

    Short Physical Performance Battery (SPPB). Minimum value: 0; Maximum value 12. Score 0-3: severe limitations; score 4-9: intermediate limitations; score 9-12: normal function.

  2. Effect of 2EAT dietary treatment on walking distance

    Time frame: At baseline (week 0), in week 13 (halfway), in week 26 (end), and optional follow-up (week 52)

    400 meter walk test (MWT) in seconds (s)

  3. Effect of 2EAT dietary treatment on muscle strength

    Time frame: At baseline (week 0), in week 13 (halfway), in week 26 (end), and optional follow-up (week 52)

    Hand Grip Strength (kg)

  4. Effect of 2EAT dietary treatment on fat free mass

    Time frame: At baseline (week 0), in week 13 (halfway), in week 26 (end), and optional follow-up (week 52)

    Fat free mass (in kg) via BODPOD air displacement plethysmograph

  5. Effect of 2EAT dietary treatment on LDL-cholesterol

    Time frame: At baseline (week 0), in week 12 (halfway), in week 26 (end)

    Serum LDL-cholesterol (mmol/L)

  6. Effect of 2EAT dietary treatment on HDL-cholesterol

    Time frame: At baseline (week 0), in week 12 (halfway), in week 26 (end)

    Serum HDL-cholesterol (mmol/L)

  7. Effect of 2EAT dietary treatment on total cholesterol

    Time frame: At baseline (week 0), in week 12 (halfway), in week 26 (end)

    Serum total cholesterol mmol/L)

  8. Effect of 2EAT dietary treatment on triglycerides

    Time frame: At baseline (week 0), in week 12 (halfway), in week 26 (end)

    Serum triglycerides (mmol/L)

  9. Effect of 2EAT dietary treatment on long-term blood glucose concentration

    Time frame: At baseline (week 0), in week 12 (halfway), in week 26 (end)

    HbA1c (mmol/mol)

  10. Effect of 2EAT dietary treatment on insulin resistance

    Time frame: At baseline (week 0), in week 12 (halfway), in week 26 (end)

    Homeostasis Model Assessment of Insulin Resistance (HOMA-IR) (values >2 indicate insulin resistance)

  11. Effect of 2EAT dietary treatment on inflammation

    Time frame: At baseline (week 0), in week 12 (halfway), in week 26 (end)

    High sensitivity CRP (mg/L)

  12. Effect of 2EAT dietary treatment on vitamin B12 levels

    Time frame: At baseline (week 0), in week 12 (halfway), in week 26 (end)

    Serum vitamin B12 (pg/mL)

  13. Effect of 2EAT dietary treatment on body iron stores

    Time frame: At baseline (week 0), in week 12 (halfway), in week 26 (end)

    Serum ferritin (mcg/L)

  14. Effect of 2EAT dietary treatment on blood haemoglobin concentration

    Time frame: At baseline (week 0), in week 12 (halfway), in week 26 (end)

    Blood haemoglobin (mmol/L)

  15. Effect of 2EAT dietary treatment on vitality

    Time frame: At baseline (week 0), in week 13 (halfway), in week 26 (end), and optional follow-up (week 52)

    De Nederlandse vitaliteitsmeter (VITA-16 questionnaire). Minimum value: 0; Maximum value 7. Higher scores indicate more vitality.

  16. Effect of 2EAT dietary treatment on quality of life

    Time frame: At baseline (week 0), in week 13 (halfway), in week 26 (end), and optional follow-up (week 52)

    Short-Form-36 questionnaire (SF-36) Minimum value: 0; Maximum value 100. Higher scores indicate better health-related quality of life. A score of 0 indicates very poor health-related quality of life, whereas a score of 100 indicates a very good health-related quality of life.

  17. Effect of 2EAT dietary treatment on carbohydrate intake

    Time frame: At baseline (week 0), in week 13 (halfway), in week 26 (end), and optional follow-up (week 52)

    Three-day food record on carbohydrate (g/day)

  18. Effect of 2EAT dietary treatment on fat intake

    Time frame: At baseline (week 0), in week 13 (halfway), in week 26 (end), and optional follow-up (week 52)

    Three-day food record on fat (g/day)

  19. Effect of 2EAT dietary treatment on saturated fat intake

    Time frame: At baseline (week 0), in week 13 (halfway), in week 26 (end), and optional follow-up (week 52)

    Three-day food record on saturated fat (g/day)

  20. Effect of 2EAT dietary treatment on fiber intake

    Time frame: At baseline (week 0), in week 13 (halfway), in week 26 (end), and optional follow-up (week 52)

    Three-day food record on fiber (g/day)

  21. Effect of 2EAT dietary treatment on calcium intake

    Time frame: At baseline (week 0), in week 13 (halfway), in week 26 (end), and optional follow-up (week 52)

    Three-day food record on calcium (mg/day)

  22. Effect of 2EAT dietary treatment on iron intake

    Time frame: At baseline (week 0), in week 13 (halfway), in week 26 (end), and optional follow-up (week 52)

    Three-day food record on iron (mg/day)

  23. Effect of 2EAT dietary treatment on zinc intake

    Time frame: At baseline (week 0), in week 13 (halfway), in week 26 (end), and optional follow-up (week 52)

    Three-day food record on zinc (mg/day)

  24. Effect of 2EAT dietary treatment on magnesium intake

    Time frame: At baseline (week 0), in week 13 (halfway), in week 26 (end), and optional follow-up (week 52)

    Three-day food record on magnesium (mg/day)

  25. Effect of 2EAT dietary treatment on selenium intake

    Time frame: At baseline (week 0), in week 13 (halfway), in week 26 (end), and optional follow-up (week 52)

    Three-day food record on selenium (mcg/day)

  26. Effect of 2EAT dietary treatment on vitamin B1 intake

    Time frame: At baseline (week 0), in week 13 (halfway), in week 26 (end), and optional follow-up (week 52)

    Three-day food record on vitamin B1 (mg/day)

  27. Effect of 2EAT dietary treatment on vitamin B2 intake

    Time frame: At baseline (week 0), in week 13 (halfway), in week 26 (end), and optional follow-up (week 52)

    Three-day food record on vitamin B2 (mg/day)

  28. Effect of 2EAT dietary treatment on vitamin B6 intake

    Time frame: At baseline (week 0), in week 13 (halfway), in week 26 (end), and optional follow-up (week 52)

    Three-day food record on vitamin B6 (mcg/day)

  29. Effect of 2EAT dietary treatment on folic acid intake

    Time frame: At baseline (week 0), in week 13 (halfway), in week 26 (end), and optional follow-up (week 52)

    Three-day food record on folic acid (mcg/day)

  30. Effect of 2EAT dietary treatment on vitamin B12 intake

    Time frame: At baseline (week 0), in week 13 (halfway), in week 26 (end), and optional follow-up (week 52)

    Three-day food record on vitamin B12 (mcg/day)

  31. Effect of 2EAT dietary treatment on vitamin C intake

    Time frame: At baseline (week 0), in week 13 (halfway), in week 26 (end), and optional follow-up (week 52)

    Three-day food record on vitamin C (mg/day)

  32. Effect of 2EAT dietary treatment on vitamin D intake

    Time frame: At baseline (week 0), in week 13 (halfway), in week 26 (end), and optional follow-up (week 52)

    Three-day food record on vitamin D (mcg/day)

  33. Effect of 2EAT dietary treatment on vitamin E intake

    Time frame: At baseline (week 0), in week 13 (halfway), in week 26 (end), and optional follow-up (week 52)

    Three-day food record on vitamin E (mg/day)

  34. Effect of 2EAT dietary treatment on behavior, dimension "diffuse emotions"

    Time frame: At baseline (week 0), in week 13 (halfway), in week 26 (end), and optional follow-up (week 52)

    Nederlandse Vragenlijst Eetgedrag (NVE) questionnaire on dimension "diffuse emotions".

    Sum questions 3, 8, 10, 28 and divide by 4. Minimal score: 0; maximal score: 5. A score of 5 means the individual has a lot of diffuse emotions, a score of 0 means no diffuse emotions.

  35. Effect of 2EAT dietary treatment on behavior, dimension "clearly described emotions"

    Time frame: At baseline (week 0), in week 13 (halfway), in week 26 (end), and optional follow-up (week 52)

    Nederlandse Vragenlijst Eetgedrag (NVE) questionnaire on dimension "clearly described emotions".

    Sum questions 1, 5, 13, 16, 20, 23, 25, 30, 32 and divide by 9. Minimal score: 0; maximal score: 5. A score of 5 means the individual has clearly described emotions, a score of 0 means no clearly described emotions.

  36. Effect of 2EAT dietary treatment on behavior, dimension "emotional eating"

    Time frame: At baseline (week 0), in week 13 (halfway), in week 26 (end), and optional follow-up (week 52)

    Nederlandse Vragenlijst Eetgedrag (NVE) questionnaire dimension "emotional eating".

    Sum questions 1, 3, 5, 8, 10, 13, 16, 20, 23, 25, 28, 30, 32 and divide by 13. Minimal score: 0; maximal score: 5. A score of 5 means the individual is a very emotional eater, a score of 0 means no emotional eating.

  37. Effect of 2EAT dietary treatment on behavior, dimension "external eating"

    Time frame: At baseline (week 0), in week 13 (halfway), in week 26 (end), and optional follow-up (week 52)

    Nederlandse Vragenlijst Eetgedrag (NVE) questionnaire dimension "external eating".

    Sum questions 2, 6, 9, 12, 15, 18, 21, 24, 27, 33 and divide by 10. Minimal score: 0; maximal score: 5. A score of 5 means the individual is a very external eater, a score of 0 means no external eating.

  38. Effect of 2EAT dietary treatment on behavior, dimension "diet-oriented eating"

    Time frame: At baseline (week 0), in week 13 (halfway), in week 26 (end), and optional follow-up (week 52)

    Nederlandse Vragenlijst Eetgedrag (NVE) questionnaire dimension "diet-oriented eating".

    Sum questions 4, 7, 11, 14, 17, 19, 22, 26, 29, 31 and divide by 10. Minimal score: 0; maximal score: 5. A score of 5 means the individual is a very diet-oriented eater, a score of 0 means no diet-oriented eating.

  39. Process evaluation of the 2EAT dietary treatment

    Time frame: At week 26 (end)

    Paper-based questionnaire with open questions

  40. End evaluation of the 2EAT dietary treatment

    Time frame: Optional follow-up (week 52)

    Paper-based questionnaire with open questions

Study contacts

Contact information is provided by the study sponsor or research team.

Sjors Verlaan

CONTACT

[email protected]

+31657442955

Susanne Wildemast

CONTACT

[email protected]

+31623492734

Sponsors and collaborators

Lead sponsor

Amsterdam University of Applied Sciences

Other

Registry information

Acronym: 2EAT

Important dates

Study start
2024
Primary completion
2026
Study completion
2027
First posted
Feb 24, 2026
Registry last updated
Feb 24, 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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