A specific gut microbe may hold the key to better metabolic health and healthier body fat distribution in overweight people, researchers have discovered.

The microbe known as Akkermansia muciniphila is linked to lower levels of fasting blood glucose and fats, key factors in the development of diabetes and heart disease.

In healthy people the bacterium makes up three-to-five percent of the gut's bacterial ecosystem and is associated with a diet rich in insoluble fiber.

Researchers put 49 obese or overweight people on a six-week low-calorie diet with extra protein and fiber.

At the start, they found that those people already with abundant A. muciniphila in their guts had lower fasting blood glucose and insulin levels, a smaller waist-to-hip and a smaller fat cell volume beneath their skin.

Afterward the experiment, researchers found these same people showed a stronger improvement in their metabolic profile and body fat distribution than those people with lower levels of the microbe, they said in the online journal Gut.

Foods high in insoluble fiber include whole grains, nuts, seeds, brown rice, celery, cabbage, onions, and tomatoes.