Scientists from Virginia Tech’s Department of Human Nutrition, Foods and Exercise recruited 20 non-obese young men aged between 18 and 30 to participate in the study. The men were randomly assigned to receive a high fat diet with or without probiotics in a milkshake for four weeks. Those that supplemented their high fat diet with the probiotic milkshake had a lower body mass and fat accumulation than those taking the placebo milkshake.
The study adds to the emerging body of evidence that gut microflora impacts metabolic factors and obesity. In 2006 researchers from Washington University in St. Louis reported that microbial populations in the human gut are different between obese and lean people; and that when the obese people lost weight their microflora reverted back to that observed in a lean person, suggesting that obesity may have a microbial component.[i]
 Obesity, December 2015, Vol. 23, Issue 12, pp 2364-2370
Nature, Vol. 444, pp 1022-1023, 1027-1031