The human body contains 10-100 times more microorganisms (mostly bacteria but also archaea, eukaryotes, and viruses) than it does its own human cells. This is referred to as the human microbiome. Most of the organisms of the human microbiome inhabit the intestines; they are also found in the nose, vagina, and on the skin.
It's no secret that the U.S. diet is woefully unhealthy. According to the University of Washington's U.S. Burden of Disease Collaborators, dietary factors are associated with about 530,000 of the 2.7 million annual U.S. deaths. The World Health Organization lists poor diet as a major contributor to deaths from chronic disease throughout the world (Reference 1). The culprits are easy to identify: too much refined sugar, too much salt, too little fruit and vegetable consumption, and too much red meat. Add too much alcohol consumption if you want to consider alcohol a food. Our current state of unhealthy, low quality cheap food – a product of federal government agricultural policy in the 1970's – is so entrenched that consumers must expend considerable effort to acquire nutritious food on their own and they must demand policy changes to enhance the public's health as a counter force to the food industry. Such changes are not rocket science, nor do they require gobs of nutrition research. Making the U.S. diet healthy is a matter of will.
Prominent nutrition researchers have proposed (References 2 and 3 below) the following policy changes to promote a healthier food supply that would improve diet quality, prevent disease, and enhance well-being.