Lamb does fall into the red meat category. What makes a meat a “red meat”? The amount of myoglobin in animal muscles determines the color of the animal’s meat. Red meats have a high myoglobin content, which a protein is found in muscle that changes to red when it’s mixed with oxygen. As a red meat, lamb inherently contains more zinc and iron than non-red meats.
One ounce of regular lamb (not grass-fed) has the same number of calories
as grass-fed beef but actually has more health-promoting omega 3 fatty
acids. People also get worried about lamb’s fat content, but lamb actually
can have less marbling of fat within the meat compared to beef. Most of lamb
meat’s fat is around the outside and can easily be trimmed.
Lamb typically has a milder flavor compared to mutton. So what is mutton
then? The common mutton definition is flesh of a mature sheep at
least one year old. So mutton is the meat of a sheep that’s over the age of
one. There’s also yearling mutton or hogget, which are usually between one and
two years of age.