Conclusions: Early gut microbiota modulation with probiotics may modify the growth pattern of the child by restraining excessive weight gain during the first years of life. This novel observation calls for further epidemiological and clinical trials, with precise data on early growth patterns and on confounding factors influencing weight development. International Journal of Obesity (2010) 34, 1531-1537; doi:10.1038/ijo.2010.50; published online 16 March 2010