Plant-focused protein-rich weight-loss program for adults 55+ with obesity
Plant-based Protein-rich Weight Loss Intervention in 55+ Adults With Obesity
This program will test whether shifting most protein to plant sources (at least 60%) while following a calorie-restricted diet helps adults 55+ with obesity lose weight and keep muscle over three to six months.
Quick facts
| Phase | Not applicable |
|---|---|
| Study type | Interventional |
| Enrollment | 200 (estimated) |
| Ages | 55 Years and up |
| Sex | All |
| Sponsor | Amsterdam University of Applied Sciences Academic / other |
| Locations | 1 site (Amsterdam, South Holland) |
| Trial ID | NCT07429136 on ClinicalTrials.gov |
What this trial studies
Participants are randomized to a diet where ≥60% of protein comes from plant sources or to a diet where ≥60% comes from animal sources, combined with an energy-restricted plan (−500 kcal/day) and a protein target around 1.2 g/kg/day (minimum 0.8 g/kg/day). The six-month intervention includes four individual consultations, five group meetings, three 24-hour dietary recalls, and provision of a workbook and recipe book. Outcomes of interest include achievement of the plant-based protein shift, weight loss, and changes in skeletal muscle mass measured at three and six months. The program is delivered at Hogeschool van Amsterdam and targets independently living older adults with obesity who can communicate in Dutch.
Who should consider this trial
Good fit: Ideal candidates are adults aged 55 or older with obesity (BMI >30 kg/m2 or BMI >27 kg/m2 with elevated waist circumference) who live independently, can understand Dutch, and are willing to consent and notify their general practitioner.
Not a fit: People already following a fully vegetarian or vegan diet, those with recent bariatric surgery, current active medical treatments that interfere (such as certain weight-loss medications or systemic cancer therapy), severe cognitive impairment, or very limited life expectancy are unlikely to benefit or are excluded.
Why it matters
Potential benefit: If successful, this approach could provide a practical way for older adults to lose weight while preserving muscle and improving overall diet quality.
How similar studies have performed: Previous research shows higher-protein diets can help preserve muscle during weight loss and plant-based diets offer cardiometabolic advantages, but randomized head-to-head comparisons of predominantly plant versus animal protein in older adults are limited.
Eligibility criteria
Show full inclusion / exclusion criteria
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
Where this trial is running
Amsterdam, South Holland
- Hogeschool van Amsterdam — Amsterdam, South Holland, Netherlands (Recruiting)
Study contacts
- Principal investigator: Peter Weijs — Amsterdam University of Applied Sciences
- Study coordinator: Susanne Wildemast
- Email: s.wildemast@hva.nl
- Phone: +31623492734
How to participate
- Review the eligibility criteria above with your treating physician.
- Visit the official trial page on ClinicalTrials.gov for the most current contact information and recruitment status.
- Contact the listed study coordinator or principal investigator to request pre-screening. Pre-screening is free and never obligates you to enroll.