Is there any truth to it? No, but maybe they are counting on another four years of anti-science, advocacy-based leadership and getting a head start. In their agency newsletter, they provided tips on how to reduce environmental impact while eating in the department cafeteria - they suggested not eating meat.
They derived that claim from a UN report which copied it from a dubious claim in a book which lifted it from a 1986 newspaper article quoting an activist who made it up - basically, the same way the UN gets most of its science. It was a nice, round number so simple even anti-science activists could remember it. It caught on. Seriously, in activism that is how these claims become mantra. The School of Public Health at Johns Hopkins University even has a website devoted to it, claiming that going meatless will prevent cancer, cardiovascular disease, diabetes and obesity. Oh, and solve global warming. That's $1 billion of your tax dollars per year right there, folks. Thanks, Johns Hopkins.
Iowa Senator Chuck Grassley, who represents a lot of farmers, flipped out after the National Cattleman’s Beef Association denounced the USDA Any-Food-Except-Meat advocacy. Politico quotes his Twitter account, “I will eat more meat on Monday to compensate for stupid USDA recommendation abt a meatless Monday."
Even Al Gore knew better than to screw with Iowa farmers. He frankly admitted he only claimed ethanol was solid science just to get votes from the midwest. After the National Cattleman’s Beef Association called it part of an extremist vegetarian agenda, the Agriculture Department said that newsletter recommendation was made "without proper clearance" and removed it. You need clearance for a newsletter? How about only hiring people who know what they are talking about instead of activists who like making a newsletter a political football during election season?
Whoever made that claim for the USDA must also have read the anti-science nonsense claiming it takes 140 liters of water to make a cup of coffee and boycotted that also - because they clearly are sleeping on the job.