According to USDA data on food consumption per capita, U.S. meat consumption fell from about 2004 to 2010 (the most recent data available).
Beef consumption peaked in 2002 and has fallen about 12% since then. Pork consumption peaked in about 1999 and has fallen about 11% since then. And I had not realized that chicken consumption peaked in about 2006 and has fallen almost 5% since then.
Total combined consumption of beef, pork, and chicken peaked in about 2004 and has fallen more than 6% since then.
I think these trends likely are driven both by economic recession and by increasing health and environmental awareness.
Americans consume substantially more beef, pork, and chicken than is necessary for a balanced and healthy diet. The federal government's mainstream advice on diet and health, MyPlate, suggests that about a quarter of the dinner plate can come from the protein group (which includes fish, seafood, beans, peas, soy foods, nuts, and eggs, in addition to beef, pork, and chicken).
The unusually high U.S. consumption of beef, pork, and chicken also raises environmental concerns, with implications for water quality (when nutrients in manure reach water sources) and land use (because of the large amounts of animal feed that are converted comparatively inefficiently into meat-based foods).
It is worth mentioning that meat is a good source of protein and several other nutrients, but these nutrients are not currently under-supplied in U.S. diets. Similarly, animal agriculture is a particularly sensible use of certain grasslands that are environmentally unsuitable for crop production, but this grass-based production system is not where most of our beef, pork, and chicken comes from.
Overall, I don't think the government should be too pushy when it comes to influencing people's diets. It seems quite wise simply to accept and accomodate the recent market-driven downward trends in meat consumption, without taking government action to oppose them.
These trends are a good thing for our health, environment, and economy.
Source: interactive chart by the author using USDA food availability data.
Update (later the same day): I just saw that Steve Baragona at Voice of America yesterday described this same trend. I had been thinking about this topic, because my colleague Paul McNamara mentioned related work on trends in vegetarian consumption by a student in his department at the University of Illinois, Daniel Karney.