Food Value
filed in health on Dec.11, 2009
Since carbohydrate are composed of units consisting of a carbon atom and a molecule of water, one molecule of oxygen will be required to oxidize a unit to CO 2 and water: C – H2 O + O2 = C O2 + H O2. The molecular respiratory quotient O2 consumed / CO 2 produced is therefore 1.00. The combustions of 1 gram of glucose yield about 3.8 kcal, while 1 gm of starch yields 4.1 kcal. The difference arises from the smaller proportional of water in starch.
Sucrose and lactose cannot be utilized at all, and maltose only to a small extent (by the intervention of amylase), by the tissues. If they gain access to the body, therefore, they are quantitatively excreted in the urine, since the traverse, the glomerular filter freely and are not appreciably reabsorbed from the renal tubules. [Read the rest of this entry...]
Glucose, fructose, galactic, and certain pentose are freely absorbed from the intestines and are found in the blood immediately after their absorption. All of them can be detected in the tissues of animals, whether the animals are fed the fasted. In the pat absorptive state, however, glucose alone is found in the Free State in appreciable quantities in blood or tissues. Moreover, the injections and ingestion of any one of the hexodes increase the quantity of glucose or its polymer, glycogen, in the body. This fact indicate these hexodes can be derived from and converted to glucose, which is the form in which carbohydrate is transported and the general medium of exchange in its metabolism. The tissues of the normal animal always contain fructose; but only in the form of esters of phosphoric acid, intermediary 
The three primary foodstuffs, carbohydrate, fat and protein, in addition to providing energy for the conduct of vital activities, supply the major proportion of the structural materials of the body and the machinery by which the energy derived from their combustion is converted to useful activities. It has been proposed that the metabolic processes be considered less than two headings, energy metabolism and operative metabolism. The over – all results of the former have been described in the preceding chapter. This and the two following chapters will be devoted to the discussion of the nature of the processes by which the three foodstuffs are oxidized, their intermediary metabolism, and their operative functions. All three foodstuffs are, within limits, interchangeable for purpose of energy production; but each one of the three is indispensable because it has individually specialized operative functions. These are so interlocked 
The food intake is controlled by centers in the hypothalamus. In the lower animals this control is so well adjusted that, even with an excess of available food, only such amounts as are needed are consumed. In the human, on the other hand, appetite and hunger are modified by many extraneous factors which alter the normal control of body weight. No abnormality in metabolic function has been demonstrated in the obese. Although constitutional factors determine the body builds of an individual, there is no evidence to suggest that such factors play a part in the pathogenesis of obesity except in so far as they may effects the psycho logic make – up and personality of the individual, including his neuromuscular activity and mode of life. Only in cases in which obesity is a result of organic lesions affecting the hypothalamic control of appetite, in such conditions as is let cell tumors of the pancreas and other causes of 
