Monitoring nutritional status during infancy, childhood, and adulthood is essential because good quality diet during growth is vital to cover the cognitive and physical demands, supply enough energy stores for illnesses and pregnancy and avoid adult nutrition-associated diseases. Thinness cases and lack of dietary diversity among learners in various education stages are common nutritional problems. A cross-sectional survey was carried out for the assessments of thinness cases and dietary diversity among the learners in various education stages in Taif Region, Saudi Arabia in August, 2020. A total of randomly selected 1602 respondents who fulfilled the exclusion and inclusion criteria (n=364 primary schools, n=410 middle schools, n=321 high schools, and n=507 university students) were examined and efficiently completed the survey. The survey comprised of socio-demographic characteristics, questions about health problems, adequate dietary diversity, habits, food item consumption, and nutritional knowledge test based on the student's theory and behaviors. The prevalence of thinness status among university students was very obvious (22%) and found to be mild followed by moderate (11%) and (0.4%) severely thin. The prevalence of severe thinness was the highest among primary school participants (28%). The prevalence of moderate thinness was reported slightly similar among middle and high school participants (29% and 32%, respectively). The highest prevalence of thinness cases was found in students from rural areas, while the lowest values were observed in those from urban areas. Students from large family size were more likely to be thin as compared to students from small size families. Students whose mothers were illiterate or had low formal education were more likely to be thin compared to those students whose mothers had completed university education or above. Further, 78% of primary school students reported meal skipping due to lack of appetite, while shape maintaining for the meal was accounted for 50% for middle school students as the main reason for the meal skipping. Snacking was also reported to be at a high rate among primary and high school students as 76% and 83% of the students mentioned having snacks, respectively. A higher frequency of light physical exercise was established for primary school pupils (81%), while university students reported (34%) as moderate. Almost all students had a low level of eating cereals, fruits and vegetables, while high schools and university students had a high-level consumption of fruits, animal-based foods and nutritional supplements. High school students had an excellent score 37% for nutrition knowledge. Education stage of learners was found to have direct influence on thinness, dietary diversity and food consumption frequency of the respondents. Consequently, nutritional education may positively affect the whole student's ability for good diet choices in the way to ensure a healthier status. The knowledge of nutrition education combined with physical exercise programmers may contribute to strengthening of the healthy eating messages at the various educationstages
