Losing weight is not easy. For many people, it takes months of dieting and exercising to shed the pounds they have gained over the Thanksgiving holiday. There are others who spend a lot of money on yo-yo diets in order to be beach-body ready.

There are many factors that affect how quickly people lose weight. In general, it is easier for men to see results following their participation in a weight management program. Furthermore, genetics play a big part in weight gain and weight loss.

According to a recent study conducted by scientist from the Weizmann Institute of Science in Israel, yet another factor might be what is keeping you from achieving and keeping your goal weight.

Eran Segal and Eran Elinav, authors of the study as reportd by Fox News, conducted an experiment aiming to prove the effect of gut microbiome in facilitating weight gain following a successful diet program.

The pair observed mice as part of their experiment. The results show that mice who lost weight have altered gut microbiomes that persist many months after the diet has lapsed. The altered gut microbiome contributed to the rapid weight gain following the yo-yo weight loss program.

In order to test the validity of their results, they introduced the altered mnicrobiome to several mice that have not been exposed to yo-yo diets. The same rapid weight gain happened in the test subjects.

Segal explain that the microbiome itself is not sufficient in facilitating weight gain. However, once the diet lapses and regular and indulgent eating patterns return, gaining weight becomes easier and faster.

"The microbiome by itself is not sufficient to produce this (rapid weight again) effect, but it's the diet plus the microbiome,"

At present, the team is working to find out whether the same thing happens to human microbiomes following adherence to a yo yo diet.