Q: When we're advised to eat less red meat, does that include lamb? (And is lamb really better for the environment than beef?)
A: Lamb is a "red meat" because it’s high in myoglobin, a protein in muscle that turns red when combined with oxygen. The same is true of beef, pork, and veal. Poultry is a so-called "white meat" because it has less myoglobin.
One problem with red meat is that it is usually high in saturated fat. But this varies quite a bit. In fact, some cuts of lamb, beef, and pork are leaner than some higher-fat poultry (chicken wings or thighs, for instance, or duck). Red meat does contain more iron and zinc.
If you like lamb, choose leaner cuts such as those from the leg and loin, and trim all visible fat. The American Lamb Board has been marketing lamb as "lean," claiming it has only 175 calories and 8 grams of fat (3 grams saturated) in 3 ounces cooked. But this is an average of all cuts and is misleading. Many lamb cuts, including some rib and shoulder cuts, have more than 250 calories and 15 grams of fat in 3 ounces; a few cuts have more than 300 calories and 25 grams of fat. And 3 ounces is a small portion.
As for the environment: All meat production is more energy-intensive and polluting than growing plant foods, especially when done in industrial feedlot operations—and nothing more so than beef. Much lamb is pasture-raised in small operations, but it is increasingly being grain-finished in factory feedlots. And about half the lamb we eat is shipped all the way from New Zealand or Australia, which, even if production there is efficient, still adds to carbon emissions. You can try to find local pasture-raised lamb, but the best step for both your health and the environment is to eat less meat overall.