We have all known those people who eat the same things we eat, sometimes a lot more, and never gain weight. So that must mean they are expending more calories, right? If you stick with the old calories in, calories out theory that would be the case. However, new research shows that calories that count are those extracted by your digestive enzymes and the trillions of bacteria in your intestine.
People whose gut bacteria are better at digesting fats and carbs than their neighbor’s will absorb all 1,500 calories in a Friendly’s Ultimate Grilled Cheese BurgerMelt, while the neighbor will absorb fewer.
A study done at Washington University showed that obese mice and slim mice have different populations of gut bacteria. Crucially, they showed that the bacteria caused obesity, rather than obesity producing a specific mix of bacteria. When the scientists plucked bacteria called Firmicutes from obese mice, then put them in the bacteria-free guts of mice raised in a sterile environment, the latter bulked up within 10 to 14 days—even though they ate less.
Why? Firmicutes, it seems, are more adept at liberating calories from food than are bacteria from the other common lineage, Bacteroidetes. Firmicutes can digest complex sugars that neither the mice’s own enzymes nor Bacteroidetes can, breaking them into simple sugars and fatty acids that the mice’s intestines then absorb and turn into more mouse. People harbor bacteria from these same two lineages, with the obese among us having more Firmicutes and fewer Bacteroidetes than slim people, exactly as in fat and lean mice.
The study then had 12 obese people follow either a low-fat or a low-carb diet to lose weight, the result was more Bacteroidetes and fewer Firmicutes—the profile of slim people. The more Bacteroidetes, the more weight the volunteers lost.
Although the diet experiment shows that losing weight can tip the bacterial balance away from bugs that extract the maximum calories from what we eat, what’s needed is a way to tip that balance and thereby lose weight, rather than lose weight and thereby tip the balance of gut bacteria.
So the next big push is to determine if there is another way to alter the bacteria (in a safe way) before making the dietary changes. There will certainly be those questionable marketers who will rush out with claims they can change your intestinal bacteria with their product However, at this time, there is no support for that approach.
In fact, it is possible that one component of the obesity epidemic is actually the widespread use of antibiotics which have changed the bacterial make-up of millions of Americans. This may even explain the upsurge of diabetes on the theory that the bacteria changes are altering the immune system. “I think the idea that foods, drugs, or other things in our environment might contribute to the epidemic by changing gut microbes is a distinct possibility" says Randy Seeley, an obesity researcher at the University of Cincinnati.
A study done at Washington University showed that obese mice and slim mice have different populations of gut bacteria. Crucially, they showed that the bacteria caused obesity, rather than obesity producing a specific mix of bacteria. When the scientists plucked bacteria called Firmicutes from obese mice, then put them in the bacteria-free guts of mice raised in a sterile environment, the latter bulked up within 10 to 14 days—even though they ate less.
Why? Firmicutes, it seems, are more adept at liberating calories from food than are bacteria from the other common lineage, Bacteroidetes. Firmicutes can digest complex sugars that neither the mice’s own enzymes nor Bacteroidetes can, breaking them into simple sugars and fatty acids that the mice’s intestines then absorb and turn into more mouse. People harbor bacteria from these same two lineages, with the obese among us having more Firmicutes and fewer Bacteroidetes than slim people, exactly as in fat and lean mice.
The study then had 12 obese people follow either a low-fat or a low-carb diet to lose weight, the result was more Bacteroidetes and fewer Firmicutes—the profile of slim people. The more Bacteroidetes, the more weight the volunteers lost.
Although the diet experiment shows that losing weight can tip the bacterial balance away from bugs that extract the maximum calories from what we eat, what’s needed is a way to tip that balance and thereby lose weight, rather than lose weight and thereby tip the balance of gut bacteria.
So the next big push is to determine if there is another way to alter the bacteria (in a safe way) before making the dietary changes. There will certainly be those questionable marketers who will rush out with claims they can change your intestinal bacteria with their product However, at this time, there is no support for that approach.
In fact, it is possible that one component of the obesity epidemic is actually the widespread use of antibiotics which have changed the bacterial make-up of millions of Americans. This may even explain the upsurge of diabetes on the theory that the bacteria changes are altering the immune system. “I think the idea that foods, drugs, or other things in our environment might contribute to the epidemic by changing gut microbes is a distinct possibility" says Randy Seeley, an obesity researcher at the University of Cincinnati.
So all those years you though your metabolism was shot? Or that you were just so different from other people when it came to calories? You just might have been right!
