The envelope that outweighs the filling
Once the protein math is settled, there's one more ingredient that shapes the finished taco, and it's the one that comes in a paper envelope. USDA FoodData Central's branded food records list the sodium in four national taco seasoning mixes. Multiplied out to a standard 1-ounce packet, they range from about 1,588 milligrams (Old El Paso Original) through 1,867 (Taco Bell Original) and 2,016 (Ortega Original) to about 2,364 milligrams (McCormick Original). The median is about 1,941 milligrams per packet.
For perspective, the FDA sets the Daily Value for sodium at less than 2,300 milligrams per day, and one median packet holds about 84 percent of that. The packet directions typically call for one envelope per pound of meat, and here's where cooking yield comes back into play. Because a pound of regular ground beef shrinks to about 3.4 taco portions, each portion carries a larger share of the packet, about 572 milligrams on top of the 77 milligrams already in the beef. A seasoned ground beef taco portion lands near 650 milligrams, around 28 percent of the Daily Value.
The pattern holds across every meat. Seasoning adds roughly 460 to 570 milligrams per portion to the chicken, pork and beef fillings, five to eleven times their natural sodium. For beans and eggs, allocating a packet per pound of cooked filling adds about 364 milligrams per portion. In other words, the choice of seasoning shapes the sodium in a taco far more than the choice of filling does.
There are a few ways to shift that number, and all of them are optional depending on taste. Reduced-sodium versions from Old El Paso (25 percent less sodium) and Ortega (40 percent less sodium) come in around 1,190 to 1,200 milligrams per packet, roughly 750 milligrams less than the median standard packet. Some cooks use half a packet per pound and top up with chili powder and cumin. Others build their own blend from pantry spices, which puts the salt entirely in their hands.
Toppings add sodium too. Cheese, salsa and sour cream all carry some, so the per-taco total depends on the whole build, not just the filling and seasoning. The Daily Vitality comparison of guacamole, hummus and tzatziki shows how much a single scoop of a creamy topping can vary.