A shift towards including more plant-based wholefoods and a reduction in highly processed and animal sourced foods is highlighted by the World Health Organization as a relatively simple, yet impactful way consumers can make their diets more sustainable and healthier for the planet(1). Changing the population’s diet has proven difficult and the threat of obesity and chronic disease development does not appear to have been a strong motivating factor for middle-aged and older adults. Awareness of the facilitators and obstacles that affect healthful dietary choices is important to inform design of nutrition promotion and behaviour change programs. The aim of this study was to synthesise available evidence that reported what middle-aged and older adults described about barriers and enablers to eating foods consistent with sustainable dietary patterns. A convergent integrated mixed methods systematic review was selected as the best method to answer the research question and we followed the Joanna Briggs Institute method(2). The MEDLINE, CINAHL, Scopus and PsychInfo databases were searched for studies published from January 2009 to February 2024 that reported the beliefs, opinions and attitudes of people aged 45-years and older in high-income countries about food selections and barriers and enablers to eating foods generally consistent with sustainable practices. Twenty-four studies met the inclusion criteria and had data extracted and quality critically appraised using the Mixed Methods Appraisal Tool(3). Findings were combined in a narrative review. The enablers included an understanding of environmental impacts of food; knowledge about nutritional benefits of plant foods and of sustainable eating patterns; and awareness of the health and environmental concerns about some animal food sources. The reported barriers included: cost of eating a sustainable diet; a preference for taste of animal foods; anxieties about nutritional adequacy of plant-based diets; cultural factors and no knowledge of diet and sustainability. The findings may be useful in design of education campaigns and health promotion.