A number of studies have shown that obese people have different intestinal bacteria than slim people, and that altering the microbial balance in your gut can influence your weight.
- LNYU Langone Medical Center foundancet, 2014: "We found that when you perturb gut microbes early in life
among mice and then stop the antibiotics, the microbes normalize but the effects on host metabolism are permanent," says senior author, Dr. Martin Blaser, director of the NYU Human Microbiome Program, and professor of microbiology at NYU School of Medicine. "This supports the idea of a developmental window in which microbes participate. It's a novel concept, and we're providing direct evidence for it." - British Journal of Nutrition, 2011: Rats given lactic acid bacteria while in utero through adulthood put on significantly less weight than other rats eating the same diet. They also had lower levels of minor inflammation, which has been associated with obesity.
- European Journal of Clinical Nutrition, 2010: Obese people were able to reduce their abdominal fat by nearly five percent, and their subcutaneous fat by over three percent, just by drinking a probiotic-rich fermented milk beverage for 12 weeks.
- American Journal of Clinical Nutrition, 2008: Babies with high numbers of Bifidobacteria and low numbers of Staphylococcus aureus -- which may cause low-grade inflammation in your body, contributing to obesity -- appeared to be protected from excess weight gain. This may be one reason why breast-fed babies have a lower risk of obesity, as Bifidobacteria flourish in the guts of breast-fed babies.
- Nature, 2006: Two separate but related studies found that obese individuals had about 20 percent more of a family of bacteria known as Firmicutes, and almost 90 percent less of a bacteria called Bacteroidetes than lean people. Firmicutes help your body to extract calories from complex sugars and deposit those calories in fat. When these microbes were transplanted into normal-weight mice, those mice started to gain twice as much fat.