Introduction and obejctive:
Health and nutrition education does not occupy an important position in Polish schools. Awareness of the importance of the role of the family, peer group and media in health promotion is also insufficient. The objective of the study was an attempt at diagnosing social conditioning of nutritional behaviours among junior school pupils and university students. Analyses of the conditioning of nutritional behaviour may be helpful for the introduction of new projects in the area of nutrition education.

Material and Methods:
The study was conducted in the form of a diagnostic survey, and covered 188 junior school adolescents and 84 university students. The material presented was collected on a questionnaire designed by the author. The respondents were asked about their nutritional habits, beliefs concerning the effect of various factors on eating behaviours, and health-promoting importance of the selected diets. The data were analysed by SPSS programme for Windows, version 14.0 PL. The methods used included Pearson’s chi-square test and the Kendall tau-b correlation coefficient.

Results:
The most important factors which condition nutritional behaviours were the same for junior school adolescents and university students: the pursuit of physical attractiveness, fast pace of living and eating habits at home. 70.2% of university students and 48.9% of adolescents would like to lose weight, but more teenagers than their older colleagues attempt to do so with diets or limiting food intake. Among junior school adolescents, a statistically significant correlation is observed between the perceived influence of peer group on eating behaviour and satisfaction with own body image or dieting.

Conclusions:
The reason for dieting among adolescents may not be overweight, but rather the influence of the peer group, which could be very important for health education in schools.