How The Bacteria in Your Gut Make You Fat

August 29, 2016

How Your Gut Bacteria Make You Fat


 References: Science News, Nature,    

Ok, this isn't in humans, it's in rats, but we share a lot of their basic physiology, and they are easier to cut open and examine and sample. If this holds up in humans, we will have gained quite a lot. The signal is as follows. Acetate is a two-carbon acid that is a breakdown product of both carbs and fats. It makes its way back to the brain. The brain turns on signals via the vagus nerve to the islets cells in the pancreas to make insulin. Insulin makes you store calories. 

 But that isn't all the acetate does. It also turns on ghrelin, your hunger hormone. You eat more. You gain weight. Coordinated processes by which you just pack it on. Acetate. Now the researchers found this by noting that infusing acetate causes rat pancreases to put out insulin. That was in earlier research. Feeding rats a high-fat diet also turns on acetate production. 

 Now, kill all the bacteria in the rat's gut and in a germ-free rat, see how much acetate they make. None! Restore their gut biome and watch the difference, acetate shows up, particularly on eating fat. Following the line of logic, the researchers then found that the acetate didn't do it directly. It worked through the brain, which then turned on the pancreas. 

 Now, in humans, it is known that we turn on acetate production when we eat carbs too. Humans have switched their biology in the last 5 million years to being less vegan and more fat consumers. In that process, the weight and source of acetate may have changed. But this research opens a whole new understanding of how our gut and it's population of bacteria play on our own metabolism. The production of acetate in our gut may be a big key to sort out this conundrum. 

 www.What will work for me. There is certainly contrary evidence between eating carbs versus eating fat for optimal weight loss. What is clear is that the production of fine flours containing ground-up carbohydrates is easily digestible, stimulate insulin directly instead of through gut bacteria. Fine white flour was available to us as humans only after the 1870s when John Stevens of Neenah Wisconsin, invented the high-efficiency flour mill. Then we added sugar and got extra acetate directly bypassing much of the bacterial biome. No wonder we gained weight, we are overwhelming our internal signals with free acetate. Ergo: stop eating flour and sugar, deep fried in fat: donuts.   

 Pop Quiz: ‪

1.  Rats, fed high-fat diets, make acetate in their guts which gets to their brains and turns on insulin and gherkin production. T or F?                      Answer.  That's about the sum of it. ‪

2.  Acetate is a natural breakdown product of fat and carbs? T or F?                         Answer:  True. (But in this study, it was fat in rats that set it off the most) ‪

3. The brain reacts to acetate but signaling an increase in what hormones?                      Answer:  Insulin (drives calories into storage) and gherlin (increasing appetite) ‪

4. Rat metabolism is identical to humans? T or F?                      Answer:  Close but no cigar. Humans have adapted to fat, but not to sugar and abundant flour. ‪

5.  In the rat model, acetate didn't happen without the right gut bacteria? T or F?                    Answer:   True.  That's one of the key messages of this study. Very intriguing.