To foster healthier and more sustainable eating habits, we need to better understand causes of dietary change on the individual level. This includes differentiating the factors that trigger good versus bad dietary change with regards to health and environmental impacts. The present analysis is based on a household survey with 620 respondents, of which 138 (22%) indicated that they have recently changed their diet. We find that diet changers in general eat worse than the rest of the sample, and also have a higher caloric intake. They are significantly younger, less likely to live in a relationship, and more often experienced critical life-events recently. As main motivations for dietary change, people indicate weight loss and their wish to eat healthier, while reducing environmental burden is rarely indicated as a motivational factor for dietary change. After changing their diet, respondents managed to reduce health and environmental impacts significantly. Further analysis suggests that the main facilitator for healthy and sustainable dietary change are increased sports activities. The factors negatively affecting the health and environmental effects in diet changers are breakups, time constraints relating to job obligations, and frequent restaurant visits. This suggests that having enough time to cook and to eat at home, in combination with increased physical activities facilitate change towards healthier and more sustainable eating habits.