334 MARINE FISHERIES OF NORTH CAROLINA 



courses over a period of a quarter-century, bringing to the consuming public 

 awareness of the advantages of a better diet of protective foods. 



All the above characteristics of the food market are but reflections of the 

 underlying determinants of food economics, which are to be found in the 

 physiological requirements of the animal body and in the factors of economic 

 geography. 



Physiological Basis of Food Economics. The first nutritive requirement 

 of the human body is for basal metabolism, which is the amount of food 

 energy required when the stomach is empty and the body is in complete 

 repose; it energizes the circulation of the blood, respiration, muscle tonus, 

 and other vital activities, but most of it is dissipated as heat in keeping the 

 body warmer than its surroundings; quantitatively it is mathematically 

 related to the weight and surface area of the body, and varies slightly from 

 person to person; being in adult males about 40 calories per sq. meter of body 

 surface per hour, and adult females 37 calories, or around 1800 and 1500 

 calories, respectively, per day. It is not subject to any voluntary variation 

 (except medication) or economic influence. 



In addition to the requirement of food for basal metabolism is that which 

 supplies energy for work and all other physical activity of the body. For this 

 use the body acts as an engine which transforms chemical energy of the food 

 to muscular contraction or work, with a certain amount of loss as muscular 

 heat in overcoming friction and viscosity of the tissues. This part of the food 

 intake is directly related to the amount of physical activity; it is proportion- 

 ately greater in the young than in the old, and greater in people of active 

 than in those of sedentary habits. 



The third major portion of food goes to growth of infants and children into 

 adults, including extra requirements of pregnant or lactating mothers; it is 

 the excess of total food assimilated above the requirements of basal metabo- 

 lism and physical work. In this class may be included the excess fat accumu- 

 lated by some people, especially adults in middle life. All of the food which 

 accumulates in growth and fat is accounted for in the end and returned to 

 nature in the bodies of deceased persons. 



The total of the above three requirements of food energy range from about 

 1200 to 1600 calories per day for infants and young children and 2100 

 calories for sedentary and aged women, to 2800 for moderately active men 

 and women (most of us), 3800 for boys in their teens, and 4500 for strong 

 men in the prime of life engaged at hard labor. Taken as a statistical whole, 

 the food requirement of the United States population works out at around 

 2800 to 3000 calories per capita per day, which agrees well enough with the 

 actual amounts shown in the table after allowance is made for converting 

 retail weights into food actually consumed, basic digestive inefficiency, etc. 



This brief sketch takes no account of the variations from person to person 



