Considering population aging and the adverse health consequences older adults face due to protein malnutrition, older adults’ protein intake is receiving increasing attention. Meanwhile, growing concern around the world’s environmental challenges has elucidated the crucial role of dietary choices. This study gives insight into more sustainable ways of increasing older adults’ (≥65) protein intake in the European Union (EU) to prevent protein malnutrition. A choice experiment (n = 2159) was conducted in five EU countries (the Netherlands, the United Kingdom, Poland, Finland, and Spain). Multinomial choice modeling shows that the majority of older adults accept protein-enriched burgers. Overall they prefer red meat and poultry above plant-based burgers. For red meat and poultry burgers, older adults prefer products with carbon labels indicating lower environmental impact. Latent class modeling identified four consumer segments. The largest segment (41%), “Meatlovers”, are not likely to change their red meat and poultry consumption. However, carbon labeling entails some opportunity. “Eco-friendly” consumers (28%) are willing to consume protein from more sustainable sources and herewith constitute the primary target group. “Poultry lovers” (12%) are most likely to shift their protein consumption based on health-related motives. Further research is recommended to identify sustainable protein-rich products for older adults who dislike burgers (19%). Subsequent consumer profiling indicates that intentions to consume sustainable protein-enriched burgers are associated with gender, country, importance attached to health, sustainability and familiarity, knowledge on protein and their environmental impact. In contrast, financial situation, importance attached to price, convenience, and sensory appeal are not associated with older adults’ preferences.