Abstract Objective: To identify differences in dietary quality, dietary greenhouse gas (GHG) emissions and food consumption over 20 years in a Dutch cohort. Design: Participants ( n 8932) filled out an FFQ in 1993–1997 and in 2015. The Dutch Healthy Diet index 2015 (DHD15-index) score, GHG emissions and consumption of food groups (g/4184 kJ (1000 kcal)) were compared between the time points with paired t tests. Setting: The Netherlands. Participants: European Prospective Investigation into Cancer and Nutrition – Netherlands (EPIC-NL) cohort, aged 18–65 years at baseline. Results: Total energy intake decreased by –678 (95 % CI –4908, 3377) kJ/d (–162 (95 % CI –1173, 807) kcal/d) for men and –372 (95 % CI –3820, 3130) kJ/d (–89 (95 % CI –913, 748) kcal/d) for women. DHD15-index scores increased by 11 % (from 64·8 to 71·9 points) and 13 % (from 65·2 to 73·6 points) in men and women, respectively ( P < 0·0001), mainly due to an increased (shell)fish and nuts/seeds/nut paste consumption. After energy intake adjustment, dietary-related GHG emissions increased by 5 % in men (2·48–2·61 kg CO 2 -eq/4184 kJ (1000 kcal), P < 0·0001) and were similar in women (0·4 %, 2·70–2·71 kg CO 2 -eq/4184 kJ (1000 kcal), P = 0·3930) due to the increased consumption of (shell)fish, nuts/seeds/nut paste, poultry and higher GHG-intensive red meats such as beef. Conclusions: This Dutch cohort analyses showed more healthy diets without mitigated GHG emissions over a 20-year period, at similar energy intakes. Higher consumption of (shell)fish and poultry was not yet at the expense of red and processed meat. Lower consumption of animal-based foods is needed to achieve healthier as well as environmentally friendly diets.