Unhealthy and unsustainable nutrition is a major concern globally, including in the United Arab Emirates. Although many education programs have been conducted, diet-related illnesses remain prevalent. This study aims to identify the barriers between knowledge and practice of sustainable healthy diets to achieve long-term health, among students of Zayed University in the United Arab Emirates. An online questionnaire was sent to Zayed University (ZU) students over 18 years of age, using snowball sampling. The participants achieved a mean score of 5.6 out of 11 in nutritional knowledge, and a mean score of 3.4 out of 6 in healthy habits. The only barrier that significantly affected dietary habits was not knowing how to plan a diet (p = 0.025). Accordingly, having good nutritional knowledge was significantly related to improved dietary habits (p < 0.001). In addition, school curriculums (p = 0.004), doing one’s own research (p < 0.001), and social media (p < 0.001) were significantly related to improved nutritional knowledge. The most commonly reported motivators for a healthier diet were “to keep their body healthy for a long time” and “to maintain a healthy weight” (72.6% and 70.1%, respectively). Overall, among ZU students the most significant barrier to achieving sustainable healthy nutrition was lack of knowledge. Education methods such as school curriculums, individual research, and social media were effective. Topics such as how to plan a diet, how to keep the body healthy, and how to maintain a healthy weight are of general interest.