New York, Aug 16 (IANS): Cannot resist those fatty foods even though you wish to trim down? It could be because of the bacteria living with you that can manipulate your brain to eat what they want to feed on, suggests a study.

Microbes influence human eating behaviour and dietary choices to favour consumption of the particular nutrients they grow best on, rather than simply passively living off whatever nutrients we choose to send their way, the researchers noted.

"Bacteria within the gut are manipulative," said corresponding author on the paper Carlo Maley from University of California San Francisco in the US.

"There is a diversity of interests represented in the microbiome, some aligned with our own dietary goals, and others not," Maley explained.

This diverse community of microbes, collectively known as the gut microbiome, may influence our decisions by releasing signaling molecules into our gut, the authors said.

Because the gut is linked to the immune system, the endocrine system and the nervous system, those signals could influence our physiologic and behavioural responses.

Gut bacteria may affect our eating decisions in part by acting through the vagus nerve, which connects 100 million nerve cells from the digestive tract to the base of the brain.

However, people can influence the compatibility of these microscopic, single-celled houseguests by deliberately altering what they ingest, Maley said, with measurable changes in the microbiome within 24 hours of diet change.

"Because microbiota are easily manipulatable by prebiotics, probiotics, antibiotics, fecal transplants, and dietary changes, altering our microbiota offers a tractable approach to otherwise intractable problems of obesity and unhealthy eating," the authors wrote.

The study based on review of the recent scientific literature appeared in the journal BioEssays.