A long-time friend of mine yesterday said that, unlike many, he hasn't gained any weight since high school: a span of two decades in which weight gain is the norm for many people. I immediately replied that he must have a good conglomeration of bacteria in his intestines that are partly responsible for his feat through their metabolism of what he eats. In fact, he eats so much with little effect on his weight that his nickname was "Worm" because a tapeworm was thought to be responsible for his physiological feat.
The conversation yesterday ultimately devolved into how his stool will be highly sought after once fecal transplantation and microbiome alteration for obesity and weight management are more fully developed.
The microbiome will be the key to understanding many diseases -- infectious and non-infectious alike -- and fine-tuning the microbiome will be a full-fledged medical speciality. With respect obesity, more and more evidence is accumulating that the microbiomes of obese patients are distinct from the non-obese. Animal studies have shown that antibiotic treatment, which by definition alters the microbiome, can cause test animals to gain weight. Transferring of the stool from obese to non-obese animals can also induce obesity. In short, multiple strains of converging evidence all provide ample evidence supporting the hypothesis that the microbiome and obesity are strongly connected.
Fecal transplantation is the current crude mechanism for altering the microbiome and is being used for refractory or recurrent C.diff (Clostridium difficile) infection. Right now the FDA is exercising "discretionary enforcement" allowing the innovative treatment to flourish (I hope they continue to exercise such discretion forever). Results have been stellar and there are efforts underway to capture the magic of the stool transplant and bottle it in a pill.
Until pills become the means of microbiome alteration, fecal transplantation will be the major mechanism for microbiome improvement. This scenario leads to the need for stool donors. These donors must have their stool screened for potential pathogens and themselves must not be obese (a fecal transplant from an overweight donor can induce obesity in the recipient).
All this discussion leads to my suggestion that my friend become a paid stool donor -- which he took as a means of saving the world (with his stool). He is eager to get to work and looks forward to being in his "office".