The race is on to breed better birds as chicken emerges as the protein of the masses ... Unlike the roughly 60 billion chickens world-wide now slaughtered for meat each year, these birds are raised for their DNA. Paul Siegel, professor emeritus of animal and poultry sciences, studies how their genes influence the way they pack on pounds and fight off disease. The research helps companies seeking to breed chickens that will grow faster on less feed and require fewer drugs to stay healthy. ... Food producers face a monumental task. At current consumption rates, the world would need to generate 455 million metric tons of meat annually by 2050, when the global population is expected to reach 9.7 billion, from 7.3 billion today. Given today’s agricultural productivity, growing the crops to feed all of that poultry, beef and other livestock would require every acre of the planet’s cropland, according to research firm FarmEcon LLC—leaving no room for raising the grains, fruits and vegetables that humans also need. ... Chicken’s rise already is changing time-honored habits. In Argentina, where grass-fed beef has long been central to daily life, per-capita poultry consumption is projected to climb 7.5% this year to a record level, while beef consumption is expected to decline 6.3%. Even in pork-loving China, the government has subsidized large-scale poultry farms and breeding operations over the past decade to increase output.

Burgers and fries have nearly killed our ancestral microbiome. ... A group of Italian microbiologists had compared the intestinal microbes of young villagers in Burkina Faso with those of children in Florence, Italy. The villagers, who subsisted on a diet of mostly millet and sorghum, harbored far more microbial diversity than the Florentines, who ate a variant of the refined, Western diet. Where the Florentine microbial community was adapted to protein, fats, and simple sugars, the Burkina Faso microbiome was oriented toward degrading the complex plant carbohydrates we call fiber. ... Scientists suspect our intestinal community of microbes, the human microbiota, calibrates our immune and metabolic function, and that its corruption or depletion can increase the risk of chronic diseases, ranging from asthma to obesity. ... Numerous factors are implicated in these disappearances. Antibiotics, available after World War II, can work like napalm, indiscriminately flattening our internal ecosystems. Modern sanitary amenities, which began in the late 19th century, may limit sharing of disease- and health-promoting microbes alike. Today’s houses in today’s cities seal us away from many of the soil, plant, and animal microbes that rained down on us during our evolution, possibly limiting an important source of novelty. ... But what the Sonnenburgs’ experiment suggests is that by failing to adequately nourish key microbes, the Western diet may also be starving them out of existence.