Both groups were also allowed to consume yoghurt, a natural source of probiotics. In addition, the probiotic group consumed one pill a day of a probiotic supplement available in stores.

The study showed that after three months, the probiotic group registered a 47.6 per cent weight loss, compared to only 38.5 per cent of the control group, said an SUSM release.

The study also found that levels of vitamin B-12 were higher in the patients taking probiotics - a significant finding, since patients often show deficiency of vitamin B-12 after having gone through gastric-bypass surgery.

These findings were published in the July issue of the Journal of Gastrointestinal Surgery.