protein helps generation of excess heat due to its SDA (specific dynamic action). For this, people living m cold

s of food values due lo cooking must get due consideration. In addition, digestibility of a food also should be considered. The water intake should be sufficient. However, in general, water is not considered as a food. Calorie need This must be satisfied. Question arises what is the calorie need of a given individual (whose diet is to be formulated) and how to calculate it ? General principles are described first. In an adult healthy man (= a man who is not gaming or losing body weight) the calorie intake = the calorie expenditure. Again, the calorie expenditure = BMR + extra calories expended during various works. BMR in a healthy adult person can be calculated, as stated before (chap. 7. 3) in short, BMR is 40 K cal or 37 K cal, per sq m per hour in males and females respectively. The determination of the body surface area has also been discussed in chap. 7. 3 How to calculate the extra calories expended ? Various methods are known although none is fully satisfactory for routine use. Most of them are applicable for a homogeneous community living, in, say, military or police barracks. Their work loads, ambient temp, etc. being known, the total calories can be calculated and from them, the extra calories needed per head can be found out. Another method is to compare with a so called 'reference man'. For example, for India, a hypothetical man, called the ICMR man (Indian Council of Medical Research) has been imagined who represents the 'average' Indian in an 'average' Indian ambient temperature The parameters of the particular person, whose diet is going to be formulated, can be compared with those of the ICMR man (the reference man), that is, his body surface area, ambient temp work routine are to be compared with the ICMR man and differences in those parameters found out. There are formulae which can now be applied to determine how much addition or subtraction of calories need be made for those differences. However, this cannot be a very practical method for routine use by a practising physician. One of the most universally applied practical method for the masses is to keep a weight chart of the person concerned. The person (who is, say, healthy adult) is allowed to eat as much as he likes (i.e. 'his appetite governs the amount of food'). Subsequently if he begins to develop obesity, the calories are cut down. Or if there is loss of body weight, calories are added However, in case of growing children this should lead to normal growth .In this connecton, it is important to have a gross idea about the calorie requirement at the beginning. Heavy manual workers (wood choppers, earth diggers, rickshaw pullers, sportsmen undergoing training for the tournament for every hour of their heavy1 muscular work, expend around 570 Kcallhr (= 2,400 Kmr) or more. Values for light and moderate works are also available. Examples of light works are shaving, dressing and light domestic works. Examples of moderate works are walking at brisk pace, soil tilling in agriculture and so on The interested reader can consult special books*. Like the ICMR man there is a FAO' (Food and Agricultural Organization, under the United Nations) man, who is an international man, or 'British reference man' (and indeed various other reference man and woman for different countries). On an 'average', moderately working healthy adult male Indians require about 2200 Kcallday. Excess intake of calories will lead to as stated earlier, obesity, whereas the reverse produces starvation; both the conditions have been discussed towards the end. The principle of'appetite governing the amount of food to be taken'works excellently with the animals. The animals, when given a free access to food, will eat only that much food required by it, not more not less. However, some human beings are prone to eat excess and develop obesity when they have free access to food (see Obesity, later, this chap). However, there is no easy and practical method (which can be used by the masses), to determine the exact number of calories needed in a given individual. The best method for him is to follow appetite governing the amount of food and watch his own weight (A rough guide for daily calorie requirement in the Western climate, provided the person is healthy adult and only moderate^ working, is between 31 to 35 Kcallkg body wt/day ] Protein Cause of indispensability: Protein of satisfactory quality must be present in the diet, m sufficient quantity. Causes of the md is pens ability of the protein are given below: Protein is required for (i) replenishment of the lost tissues, lost due to wear and tear, (ii) for accretion of new tissue during growth, convalescence and pregnancy, (iii) for synthesis of enzymes (all enzymes are protein m nature), protein hormones (e.g. insulin, parathormone, ADH etc.) and breast milk, (iv) for maintenance of concentration of plasma proteins. These are the reasons, which make food protein, an essential (N.B. essential = indispensable) article of diet Besides these reasons, there are other reasons why protein is needed by the body. (i) Extra heat: protein helps generation of excess heat due to its SDA (specific dynamic action). For this, people living m cold environment like to take extra protein m their diet By the same token, persons living in hot and tropical climates do not like to have excess protein (ii) many persons have a great fascination for such proteins like meat or fish which whets up their appetite. Quality of protein First class and second class proteins: Essential ammo acids Of the 20 ammo acids found m our body, some can be synthesized by the body whereas others cannot be synthe Davidson. S, Passmore. R, Brock. J.F, and Truswell. A: Human Nutrition and Dietetics. 6th edition, Churchill, Livingstone, 1975. sized Those ammo acids which cannot be synthesized, obviously have to be supplied from outside in the form of food Such amino acids, which must be supplied from outside are called essential (i.e., indispensable) amino acids The students of Sir A. V. Hill devised a simple way to remember the names of essential ammo acids, thus, A. V. HILL, M.P. TT where, A= Arginine, V = Valine, H = Histidine, I = Isoleucme, L = Leucine, L = Lysine M = Methionine, P = Phenylalanine, T = Tryptophan, T = Threonme (total, ten m number). [Sir AN. HILL was a great British physiologist who received a Nobel Prize for his works on muscular contraction. He, in his later part of life, entered politics and became a Member of Parliament (M.P.) from the Tory (today called Conservative) team (T.T.)1. Rose and his colleagues in the 1930s found that, at least for adult human beings, eight (not ten) ammoacids are really essential. They are isoleucme, leucme, lysme, methiomne, phenylalanine, threonine.