Yo-Yo Dieting

In the United States where 1 in 3 adults and 1 in 6 adolescents have been hit by the obesity epidemic, people tend to resort to different methods in an attempt to lose weight. One such method is dieting, which might lead to only temporary weight benefits. The post-dieting weight gain is quite common, something referred to as the ‘yo-yo effect’ or ‘weight cycling’.  Christoph A. Thaiss and colleagues at the Weizmann Institute of Science, Israel studied the patterns of weight change following dieting. They found that while the subjects of their study initially lost weight but most of them regained it during the 12 months follow-up period. Astoundingly, some subjects gained more weight post-dieting than they had initially lost. In an attempt to understand what makes it so hard to maintain weight for long, Christoph and colleagues used a rat model. The rats were fed a high-fat diet, followed by a normal chow and this cycle of dieting was repeated so that the rats lost and gained weight in a cyclic manner.  The researchers noted that recurrent dieting made the mice prone to post-dieting weight gain, something that is commonly observed in humans too.  In fact, the rats who were fed a high-fat diet in a cyclic manner gained more net weight compared to rats that were continuously fed on a high-fat diet.

Changes in the Microbiome

Next they wanted to understand what leads to this pattern of weight change in the study mice, researchers studied their gut microbiota. Interestingly, they found that the changes in the gut microbiome seemed to be responsible for the accelerated post-dieting weight gain. Could this be the key to the age old question of ‘how to stop yo yo dieting'? To take things one step further, they inoculated the microbiome from the research group of mice into the gut of another group that was not previously exposed to the yo-yo pattern of dieting.  When compared to the control population, the group of mice with altered gut microbiome experienced more significant and faster weight gain.  Furthermore, researchers also found that changes in gut microbiome lead to a decline in the levels of two flavonoids- naringenin and apigenin.  These flavonoids have a number of health benefits, one of which is controlling the expression of UCP-1 gene- a gene responsible for controlling energy expenditure.  The researchers concluded by saying that using a probiotic-based therapy following dieting may help replenish the flavonoids lost to dieting. This approach may help produce permanent weight loss and reduce the chances of post-dieting weight gain.

References

Persistent microbiome alterations modulate the rate of post-dieting weight regain
http://www.nature.com/nature/journal/vaap/ncurrent/full/nature20796.html
Overweight and Obesity Statistics
https://www.niddk.nih.gov/health-information/health-statistics/Pages/overweight-obesity-statistics.aspx