Cruz-Jentoft, A. J. et al. Sarcopenia: revised European consensus on definition and diagnosis. Age Ageing. 48, 16–31. https://doi.org/10.1093/ageing/afy169 (2019).

Article 
PubMed 

Google Scholar
 

Agostoni, C. et al. EFSA Dietary Reference Values for protein. EFSA J. https://doi.org/10.2903/j.efsa.2012.2557 (2011).

Article 

Google Scholar
 

Rand, W. M., Pellett, P. L. & Young, V. R. Meta-analysis of nitrogen balance studies for estimating protein requirements in healthy adults. Am. J. Clin. Nutr. 77, 109–127. https://doi.org/10.1093/ajcn/77.1.109 (2003).

Article 
CAS 
PubMed 

Google Scholar
 

WHO. FAO, UNU. Protein and Amino Acid Requirements in Human Nutrition: Report of a Joint WHO/FAO/UNU Expert Consultation. 935. (2007).

Bauer, J. et al. Evidence-based recommendations for optimal dietary protein intake in older people: A position paper from the prot-age study group. J. Am. Med. Dir. Assoc. 14, 542–559. https://doi.org/10.1016/j.jamda.2013.05.021 (2013).

Article 
PubMed 

Google Scholar
 

Deutz, N. E. P. et al. Protein intake and exercise for optimal muscle function with aging: recommendations from the ESPEN expert group. Clin. Nutr. 33, 929–936. https://doi.org/10.1016/j.clnu.2014.04.007 (2014).

Article 
CAS 
PubMed 
PubMed Central 

Google Scholar
 

van Rossum, C. et al. The diet of the dutch: results of the Dutch National food consumption survey 2019–2021 on food consumption and evaluation with dietary guidelines. RIVM https://doi.org/10.21945/RIVM-2022-0190 (2023).

Article 

Google Scholar
 

Verreijen, A. M. et al. Effect of a high protein diet and/or resistance exercise on the preservation of fat free mass during weight loss in overweight and obese older adults: a randomized controlled trial. Nutr. J. 16, 1–8. https://doi.org/10.1186/s12937-017-0229-6 (2017).

Article 
CAS 

Google Scholar
 

Verreijen, A. M. et al. A high Whey protein-, leucine-, and vitamin D-enriched supplement preserves muscle mass during intentional weight loss in obese older adults: A double-blind randomized controlled trial. Am. J. Clin. Nutr. 101, 279–286. https://doi.org/10.3945/ajcn.114.090290 (2015).

Article 
CAS 
PubMed 

Google Scholar
 

Memelink, R. G. et al. Effect of an enriched protein drink on muscle mass and glycemic control during combined lifestyle intervention in older adults with obesity and type 2 diabetes: A double-blind Rct. Nutrients 13, 1–15. https://doi.org/10.3390/nu13010064 (2021).

Article 
CAS 

Google Scholar
 

van den Helder, J. et al. Blended home-based exercise and dietary protein in community-dwelling older adults: a cluster randomized controlled trial. J. Cachexia Sarcopenia Muscle. 11, 1590–1602. https://doi.org/10.1002/jcsm.12634 (2020).

Article 
PubMed 
PubMed Central 

Google Scholar
 

van den Helder, J. et al. Digitally supported dietary protein counseling changes dietary protein intake, sources and distribution in community-dwelling older adults. Nutrients 13, 1–16. https://doi.org/10.3390/nu13020502 (2021).

Article 
CAS 

Google Scholar
 

FAO. Dietary protein quality evaluation in human nutrition: Report of an FAO Expert Consultation. 92. (2013).

Gorissen, S. H. M. et al. Ingestion of wheat protein increases in vivo muscle protein synthesis rates in healthy older men in a randomized trial. J. Nutr. 146, 1651–1659. https://doi.org/10.3945/jn.116.231340 (2016).

Article 
CAS 
PubMed 

Google Scholar
 

Kurpad, A. V. & Protein quality and sources. In: Caballero B, editor. Encyclopedia of Human Nutrition. Third Edit, 123–30. (2013)

van Vliet, S., Burd, N. A. & van Loon, L. J. C. The skeletal muscle anabolic response to plant- versus animal-based protein consumption. J. Nutr. 145, 1981–1991. https://doi.org/10.3945/jn.114.204305 (2015).

Article 
PubMed 

Google Scholar
 

Sobiecki, J. G., Appleby, P. N., Bradbury, K. E. & Key, T. J. High compliance with dietary recommendations in a cohort of meat eaters, fish eaters, vegetarians, and vegans: results from the European prospective investigation into cancer and Nutrition-Oxford study. Nutr. Res. 36, 464–477. https://doi.org/10.1016/j.nutres.2015.12.016 (2016).

Article 
CAS 
PubMed 
PubMed Central 

Google Scholar
 

Borkent, J. W. et al. A vegan dietary pattern is associated with high prevalence of inadequate protein intake in older adults; a simulation study. J. Nutr. Health Aging. https://doi.org/10.1016/j.jnha.2024.100361 (2024).

Article 
PubMed 

Google Scholar
 

Tilman, D. & Clark, M. Global diets link environmental sustainability and human health. Nature 515, 518–522. https://doi.org/10.1038/nature13959 (2014).

Article 
ADS 
CAS 
PubMed 

Google Scholar
 

Willett, W. et al. Food in the anthropocene: the EAT–Lancet commission on healthy diets from sustainable food systems. Lancet 393, 447–492. https://doi.org/10.1016/S0140-6736(18)31788-4 (2019).

Article 
PubMed 

Google Scholar
 

Ahnen, R. T., Jonnalagadda, S. S. & Slavin, J. L. Role of plant protein in nutrition, wellness, and health. Nutr. Rev. 77, 735–747. https://doi.org/10.1093/nutrit/nuz028 (2019).

Article 
PubMed 

Google Scholar
 

Government of the Netherlands (Rijksoverheid). Tenminste houdbaar tot: Bewegen naar een duurzaam voedselsysteem. 131 (2020).

Council for the Environment and Infrastructure. (Rli). Sustainable and Healthy, Together towards a Sustainable Food System. (2018).

Health Council of the Netherlands (Gezondheidsraad). A healthy protein transition. Hague: Health Council Neth. (2023).

Janssen, M., Busch, C., Rödiger, M. & Hamm, U. Motives of consumers following a vegan diet and their attitudes towards animal agriculture. Appetite 105, 643–651. https://doi.org/10.1016/j.appet.2016.06.039 (2016).

Article 
PubMed 

Google Scholar
 

Craddock, J. C., Neale, E. P., Peoples, G. E. & Probst, Y. C. Examining dietary behaviours, diet quality, motives and supplementation use in physically active individuals following vegetarian-based eating patterns. Nutr. Bull. 47, 473–487. https://doi.org/10.1111/nbu.12592 (2022).

Article 
PubMed 
PubMed Central 

Google Scholar
 

Rickerby, A. & Green, R. Barriers to Adopting a Plant-Based Diet in High-Income Countries: A Systematic Review. Nutrients https://doi.org/10.3390/nu16060823 (2024).

Article 
PubMed 
PubMed Central 

Google Scholar
 

Kemper, J. A. Motivations, barriers, and strategies for meat reduction at different family lifecycle stages. Appetite https://doi.org/10.1016/j.appet.2020.104644 (2020).

Article 
PubMed 

Google Scholar
 

Lea, E. J., Crawford, D. & Worsley, A. Public views of the benefits and barriers to the consumption of a plant-based diet. Eur. J. Clin. Nutr. 60, 828–837. https://doi.org/10.1038/sj.ejcn.1602387 (2006).

Article 
CAS 
PubMed 

Google Scholar
 

Herrema, A. L., Westerman, M. J., Dongen, E. V. J. I., Kudla, U. & Veltkamp, M. Combined protein-rich diet with resistance exercise intervention to counteract sarcopenia: A qualitative study on drivers and barriers of compliance. J. Aging Phys. Act. 26, 106–113. https://doi.org/10.1123/japa.2017-0126 (2018).

Article 
PubMed 

Google Scholar
 

Melina, V., Craig, W. & Levin, S. Position of the academy of nutrition and dietetics: vegetarian diets. J. Acad. Nutr. Diet. 116, 1970–1980. https://doi.org/10.1016/j.jand.2016.09.025 (2016).

Article 
PubMed 

Google Scholar
 

Keller, K. & Engelhardt, M. Strength and muscle mass loss with aging process. Age Strength Loss 3. (2013).

Volpi, E., Nazemi, R. & Fujita, S. Muscle tissue changes with aging.

Moser, A., Korstjens, I. & Series Practical guidance to qualitative research. Part 1: introduction. Eur. J. Gen. Pract. 23, 271–273. https://doi.org/10.1080/13814788.2017.1375093 (2017).

Article 
PubMed 
PubMed Central 

Google Scholar
 

Green, J. & Thorogood, N. Qualitative Methods for Health Research. 4. (2018).

Albury, C. et al. Gender in the consolidated criteria for reporting qualitative research (COREQ) checklist. Int. J. Qual. Health Care. 33, 2021. https://doi.org/10.1093/intqhc/mzab123 (2021).

Article 

Google Scholar
 

Tong, A., Sainsbury, P. & Craig, J. Consolidated criteria for reporting qualitative research (COREQ): A 32-item checklist for interviews and focus groups. Int. J. Qual. Health Care. 19, 349–357. https://doi.org/10.1093/intqhc/mzm042 (2007).

Article 
PubMed 

Google Scholar
 

Reybold, L. E., Lammert, J. D. & Stribling, S. M. Participant selection as a conscious research method: thinking forward and the deliberation of emergent findings. Qualitative Res. 13, 699–716. https://doi.org/10.1177/1468794112465634 (2013).

Article 

Google Scholar
 

CBS (Statistics Netherlands), RIVM. (Dutch National Institute for Public Health and the Environment), Nutrition-Centre (Health Survey/Lifestyle Monitor, 2023).

Michie, S., van Stralen, M. M. & West, R. The behaviour change wheel: A new method for characterising and designing behaviour change interventions. Implement. Sci. 6, 1–12. https://doi.org/10.1186/1748-5908-6-42 (2011).

Article 

Google Scholar
 

Krueger, R. & Casey, M. Focus Groups: a Practical Guide for Applied Research 5th edn (SAGE, 2014).

Agan, J., Koch, L. C. & Rumrill, P. D. The use of focus groups in rehabilitation research. Work 31, 259–269 (2008).

PubMed 

Google Scholar
 

Guest, G., Namey, E. & McKenna, K. How many focus groups are enough?? Building an evidence base for nonprobability sample sizes. Field Methods. 29, 3–22. https://doi.org/10.1177/1525822X16639015 (2017).

Article 

Google Scholar
 

Poliandri, D., Perazzolo, M., Pillera, G. C. & Giampietro, L. Dematerialized participation challenges: Methods and practices for online focus groups. Front. Sociol. https://doi.org/10.3389/fsoc.2023.1145264 (2023).

Article 
PubMed 
PubMed Central 

Google Scholar
 

Braun, V. & Clarke, V. Using thematic analysis in psychology. Qual. Res. Psychol. 3, 77–101. https://doi.org/10.1191/1478088706qp063oa (2006).

Article 

Google Scholar
 

Baker, M. T., Lu, P., Parrella, J. A. & Leggette, H. R. Investigating the Effect of Consumers’ Knowledge on Their Acceptance of Functional Foods: A Systematic Review and Meta-Analysis. Foods https://doi.org/10.3390/foods11081135 (2023).

Article 
PubMed 
PubMed Central 

Google Scholar
 

Wardle, J., Parmenter, K. & Waller, J. Nutrition knowledge and food intake. Appetite 34, 269–275. https://doi.org/10.1006/appe.1999.0311 (2000).

Article 
CAS 
PubMed 

Google Scholar
 

Rousset, S., Droit-Volet, S. & Boirie, Y. Change in protein intake in elderly French people living at home after a nutritional information program targeting protein consumption. J. Am. Diet. Assoc. 106, 253–261. https://doi.org/10.1016/j.jada.2005.10.037 (2006).

Article 
PubMed 

Google Scholar
 

Visser, M., Hung, Y. & Verbeke, W. Protein Knowledge of Older Adults and Identification of Subgroups with Poor Knowledge. Nutrients https://doi.org/10.3390/nu13031006 (2021).

Article 
PubMed 
PubMed Central 

Google Scholar
 

Linschooten, J. O., Verwijs, M. H., Beelen, J., De Van Der Schueren, M. A. E. & Roodenburg, A. J. C. Low awareness of community-dwelling older adults on the importance of dietary protein: new insights from four qualitative studies. J. Nutr. Sci. 10, 1–10. https://doi.org/10.1017/jns.2021.92 (2021).

Article 
CAS 

Google Scholar
 

Beelen, J. et al. Undernutrition: Who cares? Perspectives of dietitians and older adults on undernutrition. BMC Nutr. https://doi.org/10.1186/s40795-017-0144-4 (2017).

Article 
PubMed 
PubMed Central 

Google Scholar
 

Hung, Y., Wijnhoven, H. A. H., Visser, M. & Verbeke, W. Appetite and protein intake strata of older adults in the European union: Socio-demographic and health characteristics, diet-related and physical activity behaviours. Nutrients https://doi.org/10.3390/nu11040777 (2019).

Article 
PubMed 
PubMed Central 

Google Scholar
 

Cruwys, T., Bevelander, K. E. & Hermans, R. C. J. Social modeling of eating: A review of when and why social influence affects food intake and choice. Appetite 86, 3–18. https://doi.org/10.1016/j.appet.2014.08.035 (2015).

Article 
PubMed 

Google Scholar
 

Hielkema, M. H. & Lund, T. B. Reducing meat consumption in meat-loving Denmark: Exploring willingness, behavior, barriers and drivers. Food Qual. Prefer https://doi.org/10.1016/j.foodqual.2021.104257 (2021).

Article 

Google Scholar
 

Neufingerl, N. & Eilander, A. Nutrient Intake and Status in Adults Consuming Plant-Based Diets Compared to Meat-Eaters: A Systematic Review. Nutrients https://doi.org/10.3390/nu14010029 (2022).

Article 

Google Scholar
 

Piazza, J. et al. Rationalizing meat consumption. 4Ns Appetite. 91, 114–128. https://doi.org/10.1016/j.appet.2015.04.011 (2015).

Article 
PubMed 

Google Scholar
 

Michel, M., Hartmann, F. & Siegrist, C. Consumers’ associations, perceptions and acceptance of meat and plant-based meat alternatives. Food Qual. Prefer https://doi.org/10.1016/j.foodqual.2020.104063 (2021).

Article 

Google Scholar
 

Collier, E. S. et al. Perceptions of processed foods as unhealthy: heuristic strength, prevalence, and potential implications for the protein shift. Future Foods. 10, 100445. https://doi.org/10.1016/j.fufo.2024.100445 (2024).

Article 
CAS 

Google Scholar
 

Fehér, A., Gazdecki, M., Véha, M., Szakály, M. & Szakály, Z. A comprehensive review of the benefits of and the barriers to the switch to a plant-based diet. Sustain. (Switzerland). 12, 1–18. https://doi.org/10.3390/su12104136 (2020).

Article 

Google Scholar
 

Perez-cueto, F. J. A. et al. How barriers towards plant-based food consumption differ according to dietary lifestyle: Findings from a consumer survey in 10 EU countries. Int. J. Gastron Food Sci. https://doi.org/10.1016/j.ijgfs.2022.100587 (2022).

Article 

Google Scholar
 

Macdiarmid, J. I., Douglas, F. & Campbell, J. Eating like there’s no tomorrow: public awareness of the environmental impact of food and reluctance to eat less meat as part of a sustainable diet. Appetite 96, 487–493. https://doi.org/10.1016/j.appet.2015.10.011 (2016).

Article 
PubMed 

Google Scholar
 

Mäkiniemi, J. P. & Vainio, A. Barriers to climate-friendly food choices among young adults in Finland. Appetite 74, 12–19. https://doi.org/10.1016/j.appet.2013.11.016 (2014).

Article 
PubMed 

Google Scholar