When parents think about first foods, they usually picture sweet potato, avocado, or banana. Nobody imagines handing their 6-month-old a chicken drumstick. But from a nutritional standpoint, meat makes a stronger case as a first food than any fruit or vegetable.
The reason is iron. Babies are born with iron stores that deplete around 6 months — this is the primary nutritional reason for starting solids. Breast milk is low in iron. Formula is fortified, but babies still benefit from dietary iron. And meat provides the most absorbable form of iron available.
Iron comes in two forms: heme iron (from animal sources) and non-heme iron (from plants and fortified foods). Heme iron is absorbed at a rate of 15-35%. Non-heme iron is absorbed at only 2-20%. This means the iron in 3 ounces of beef is significantly more bioavailable than the iron in a half cup of spinach — even though the spinach has a comparable amount on paper.
This doesn't mean plant-based iron is useless — it's not, especially when paired with vitamin C. But if you're going to offer one iron-rich food in the first week of solids, meat gives you the biggest nutritional return.