Weight loss and your gut bacteria

Can you alter your gut bacteria (microbiota) to lose weight? Is there a link between the microbiota and weight gain? Let’s take a glance at what the scientific research really shows.
The best scientific evidence to date shows there is no consistent correlation between weight gain and the microbiota. (1) (2) (3)
High-level evidence also suggests the microbiota does not cause weight gain. (4) One review paper even suggested – that in humans the alterations in gut microbiota are an association with rather than the cause of weight gain. (5) These findings indicate that microbiota testing has little benefit in treating weight gain.
This is confirmed by the research showing poor results when manipulating the microbiota in attempts to treat weight gain:

• Prebiotics: The best results achieved was 2.3 pounds of weight loss. (6)
• Probiotics: Studies achieved 2.2 lbs. with Lactobacillus gasseri and 3.7 lbs. with Lactobacillus rhamnosus. (7) (8)
• Fibre: The best results have been with the fiber glucomannan (7g/day) showing 8.36 pounds more weight loss than a low-calorie diet alone. (9) One review showed fiber’s average weight loss effect was 4.2 lbs. (10)
• Fecal Microbiota Transplant (FMT): A study was performed where the feces of lean men was transplanted into recipients who were overweight and had high blood sugar levels. (11) Unfortunately, there was no change in weight or body fat.

Most of the confusion about the microbiota in weight gain comes from:

1. Misinterpreting human data. For example, thinking those in the US should have the same microbiota as Africans; the microbiota that helps African’s may make those in the US constipated and fat. (12)
2. Over-extrapolation of data from animal studies. (13)
3. Examining only one side of the data.
4. The small intestine is not tested in current microbiota testing. The small intestine is responsible for 90% of caloric absorption and represents over 56% of the digestive tract. (14) The small intestine is also more prone to leaky gut and likely has the largest impact on your immune system.

Disclaimer

This article in not intended to provide medical advice, diagnosis or treatment.