This section is from the book "Practical Dietetics With Special Reference To Diet In Disease", by William Gilman Thompson. Also available from Amazon: Practical Dietetics with Special Reference to Diet in Disease.
Chicken is among the most digestible of meats for invalids, whether cooked by broiling, roasting, or boiling. The white meat is more easily digested than the dark, although it differs but slightly in chemical composition. Dark meat of fowl contains more pigment, extractives and a little more nitrogenous material than white meat. The breast of chicken may be given to a typhoid convalescent or a patient recovering from any severe illness before beef and mutton are allowed. Chicken broth is almost universally liked, and when thickened with rice, and sometimes with an egg, it forms a highly desirable invalid food.
"Broilers" contain about 20.7 per cent of proteid and 7 to 8 per cent of fat. In young chickens the dark meat contains only one per cent less proteid than the white meat and one per cent more fat.
Capon, or the emasculated cock, develops a larger proportion of white meat than the chicken, and is very digestible.
Turkey is sometimes as digestible as chicken, as to the white meat, but it is often tough, and the dark meat is much less digestible. Guineafowl and peafowl are very digestible and wholesome when young or caponised. These birds are somewhat richer in proteid than chicken, but poorer in fat.
Young pigeons are quite digestible, and the breast of a squab may be given to a convalescent from fever before other meat is allowed.
Tame ducks and geese are indigestible unless quite young and tender, on account of containing too much fat. Goose meat may sometimes hold over 40 per cent of fat, with which it is thoroughly infiltrated, and ducklings 38 per cent of fat, as against 14 per cent of proteid.
Game, such as the flesh of partridge, grouse, woodcock, snipe, quail, pheasants, wild ducks, prairie chicken, etc., is by many persons preferred when it is "high" - that is, when it has been kept long enough for putrefactive changes to occur. These may originate in the meat itself or in the viscera which have not been removed and from which the odour and flavour of commencing putrefaction are derived and penetrate the meat. When the meat itself is not perfectly fresh it may produce violent gastro-intestinal disorder, but many persons with good digestive organs are not disturbed by the consumption of such food in moderation, provided it is well cooked. The process of cooking disinfects it by heat. The fat of old birds is too strongly flavoured, and their meat is tough. Young birds are digestible if properly cooked.
The white meat of game and fowl is popularly supposed to contain less proteid, and therefore be less "heavy" as an article of diet than red meat, such as steak or roast beef. The chemical differences are, however, very slight. Chicken contains between 3 and 4 per cent more proteid than sirloin steak and about half as much fat. Red meat contains more pigment, but somewhat less of kreatin and other extractives than the white meat of chicken. The fibre of the latter is somewhat more tender, as, a rule, and hence slightly more digestible than that of beef or mutton, although the proteid content is somewhat greater. As the white meat of chicken and game is relatively expensive, patients are less likely to eat too much of it, as they may do with beef. Helen W. Atwater says:
"As far as the nutritive value alone is concerned, the general advantage of poultry over the other meats thus appears to be that, pound for pound, it contains very slightly more of the building materials needed by the body; its disadvantage is that it furnishes less of the energy-giving material than the fatter meats.
"As regards poultry of different sorts, in general the light-fleshed birds are richer in protein and poorer in fat than the others".
The clinical significance of these observations is very important, for in cases of chronic nephritis, gout, rheumatism, lithaemia and allied conditions, patients are often told that they must abstain from mutton, beef and other red meats, but are allowed to eat the white meat of chicken, turkey, etc. In reality, however, there is but little advantage in this from the standpoint of the quantity of proteid material introduced into the system and of resultant proteid waste. The question is, therefore, almost entirely one of relative digestibility, of physical rather than chemical properties, a fact which should be more widely appreciated.
Other forms of meats derived from the larger animals, such as the wild boar, wild sheep and goats, etc., are too numerous for detailed mention here, as they are rarely made use of except by hunters, explorers, or natives of wild countries. It is a peculiarity of game in general that it usually cannot be eaten continuously as long as beef without palling very much sooner upon the appetite.