Patterns of nutritional behaviours shaped in childhood and during the period of adolescents are mostly continued in adult life, and on these patterns, to a great degree, depends the risk of development of many chronic diseases. The aim of this study was to assess the relationship between dietary habits and body image perception among Polish adolescents and young adults. The study group covered 14,511 adolescents/young adults: 10,081 children attending high schools and secondary schools, and 4,428 university students. More than 87% of schoolchildren and students admitted that that they snacked between meals everyday, and 1/3 of them mentioned that they consumed meals at night. As many as 41.40% of schoolchildren, and 46.70% of students experienced the feeling of overeating at least several times a week. Analysis of the respondents BMI showed that in the group of students there were considerably more respondents obese or overweight, compared to the group of schoolchildren. Fear of gaining weight was mentioned by 9.90% of respondents, including 6.90% of those with normal body structure, 1.40% with underweight or overweight, and 0.40% of those obese. As many as 54.60% of the total number of respondents described their body structure as remaining within the normal, 23.7% - as slim, 13.9% reported that they were overweight, 6% - thin, while 1.7% considered themselves as obese. A comprehensive analysis of the data available, including attempts at dieting or gaining weight, indicated that approximately ¾ of obese respondents had undertaken attempts in the past to reduce their body weight. The importance of physical activity and healthy eating habits should be given due attention not only to prevent obesity but also other eating disorder.