Other seafood sources for high iron and B12 include oysters, trout, salmon and haddock. For people over 50 who must limit saturated fat and cholesterol, seafood sources make superior choices to meats for building up your blood.
More specifically, sedentary men ages 19 to 30 need 2,400 to 2,600 calories; 31- to 50-year-old men require 2,200 to 2,400 calories; and sedentary men over the age of 50 need 2,000 to 2,200 calories each day to maintain a healthy body weight.
So, using our same example from before, this person could potentially eat 2000 calories a day, or eat 2500 calories a day and then burn 500 through some form of exercise, or eat 2250 and burn 250, or anything similar.