Emerging evidence suggests a link between the gut microflora and metabolic factors in obesity.  As such, there is increasing interest in food-based approaches to favorably alter the bacteria composition of the GI tract to modulate specific metabolic pathways. Seoul National University (Korea) researchers studied kimchi – a mixture of cabbage and other vegetables with chili peppers the fermented version not only has concentrated flavor, but improved digestibility, as it is a good source of lactobacilli, a “friendly” GI bacteria. 

The team enrolled 24 obese women, to consume either fresh or fermented kimchi for 8 weeks. Fermented kimchi altered gene expression linked to metabolism, immunity, blood circulation, digestion, and blood pressure. As well, the investigators found that fermented kimchi raised the numbers of Bacteriodes and Prevotella, while lowering Blautia, in the gut; these changes appeared to correspond to metabolic pathway changes associated with weight/obesity.

Observing that: “fresh and fermented kimchi intervention exerted differential effects on the obesity-related clinical parameters,” the study authors write that: “ Correlations of these effects with changes in blood gene expression and gut microbial population were more evident in the fermented kimchi group than the fresh kimchi group.”

I will not extrapolate to determine whether this would help obesity but it is well established that peppers and other hot spicy foods raise the metabolic rate at which food is burned as fuel.  Due to other problems inherent in doing this long term such as damaging the epithelial tissue of the gut, I would not recommend as a sole dietary intervention but it may help someone kick off a weight loss program if balanced properly.