People in UK have the greatest weight among other Europeans - almost a quarter of women and more than 22% of men are obese. Researchers believe itis because of thecoldclimate. It turns out that bacteria, which increase the risk of obesity, thrive in low temperatures, writes The Daily Mail.

For obesity are responsible two types of intestinal bacteria - Bacteroidetes and Firmicutes. Obese people have more Firmicutes and fewer Bacteroidetes. Research of 1020 healthy volunteers from 23 countries, including Great Britain, showed: the farther from the equator, the more are Firmicutes bacteria.In cold conditions, the body adapts by increasing body weight. For this reason, healthy intestinal bacteria ratio can vary greatly depending on where one lives.

Studies on mice prone to obesity, showed, that there were more Firmicutes in their body. If the animals initially did not have gut bacteria, and then they were administered Bacteroidetesor Firmicutes, the mice, who had more Firmicutes in their body, gained more weight.

Remarkably, when obese humans were put on a diet, the same group found the proportion of Firmicutes decreased, and Bacteroidetes increased, in line with their loss of body fat. Apparently, Firmicutes contribute to more efficient extraction of energy from food. This is the key feature for organisms living in cold climate.