In the latest study, researchers compared three groups of obese mice on a high-calorie diet.
- One group was given a gastric bypass
- One was given a sham operation, and the high-calorie diet continued
- One was given the same fake operation but then fed a low-calorie diet to promote weight loss
A week later the mice who had undergone the real obesity surgery had different bacteria in their guts, with an increase in types usually seen in lean individuals and a drop in types associated with obesity.
Three weeks after surgery they had lost about 30% of their bodyweight, the researchers reported in Science Translational Medicine.
There was little change in micro-organisms present in the mice who had had sham operations, even though the group on the low-calorie diet lost just as much weight as the mice who had had the bypass surgery.
Researchers then transferred samples from the guts of the three groups of mice into other germ-free mice.
Those who received bacteria from the bypass mice, lost a significant amount of weight in two weeks but the others saw no change.
It is not yet clear how the microbes influence weight loss, but one theory is that they have an impact on metabolism.
The absence of a specific type of neuron in the brain can lead to obesity and diabetes in mice report researchers in The EMBO Journal. The outcome, however, depends on the type of diet that the animals are fed.
How Many Calories in a Food? You Might Be Surprised
One in three Americans are obese. Processed foods, microbes, one’s immune system, and cooking methods all play a role in how many calories are derived from our food.
One study found tha