Introduction: The “Keep Fit!” programme is an initiative for promoting healthy lifestyles in school­children, which uses a two-pronged approach of focusing on a balanced diet combined with regular physical activity. Hitherto, nine editions of the programme have taken place, involving more than seven million pupils attending over 8800 schools. Due to its scope and coverage being so wide, the “Keep Fit!” programme was recognised as being the largest educational programme in the European Union. The aim of the present study was to investigate the health behaviours of pupils and students in Poland, with focus on their eating habits, physical activity, self-assessed weight, psychoactive substance use, and the impact that taking part in the “Keep Fit!” programme had on changing their lifestyle.

Material and methods: The study involved cross-sectional surveys in Poland conducted in 2009 among randomly selected samples of junior high-school pupils (ages 13-16), and in 2011 of pupils attending junior high school, high school (ages 17-19), as well as university students aged 25 and younger. The questionnaire was devised by the Chief Sanitary Inspectorate (GIS). Data was analysed from correctly completed questionnaires among 9,360 and 11,863 eligible respondents in 2009 and 2011, respectively.

Results: Among eligible survey respondents, 53% (4970) in 2009 and 14% (1674) took part in the “Keep Fit!” programme. Both in 2009 and 2011 the “Keep Fit!” programme has made a significant and beneficial impact in terms of eating habits and physical activity among programme participants.

Conclusions: The “Keep Fit!” programme should be continued so as to prevent overweight, obesity, and other chronic non-communicable diseases from occurring in schoolchildren.