(From the Department of Physiology, Edinburgh University)
FOOD AND AGRICULTURE ORGANIZATION OF THE UNITED NATIONS
1. REACTIONS TO THE FIRST AND SECOND CALORIE REPORTS2. THE REFERENCE MAN AND WOMAN
3. PRACTICAL USES OF THE REPORTS
4. FUTURE POSSIBILITIES
5. DETAILED ASSESSMENT OF THE SECOND REPORT
(a) Activity and calorie requirements
(b) Body size and calorie requirements
(c) Effect of aging on calorie requirements of adults
(d) Climate and calorie requirements
(e) Requirements of children
(f) Contribution of alcohol to calorie intake
(h) Further research
6. FUTURE PUBLICATIONSTABLES
Two FAO Committees have provided reports on Calorie Requirements, the first in 1950 and the second in 1957. The question of the need for a further report has now arisen. There are two reasons for this. First, new physiological knowledge is accumulating, based on measurements of the energy expenditure of man under a variety of conditions. Secondly, the manner of life of many sections of the population is changing rapidly; mechanization could lead to greatly reduced rates of energy expenditure by man and so to reduced needs for food. Clearly a Committee could not produce a final report, suitable for all foreseeable times. Any statement of calorie requirements, to be practical, must be related to contemporary modes of life.
I have read again with care the Report of the Second Committee, many publications in the scientific literature and also private communications to the FAO Secretariat; I have had discussions with many nutritionists, especially those attending the recent International Congress in Edinburgh, and also with members of the staff of FAO in Rome and WHO in Geneva. As a result, I am satisfied that the Report of the Second Committee remains a practical working document. A Third Committee, working in the near future, would only be able to make minor modifications in the recommendations at present in use. The scientific basis for any such changes would be weak and the practical result small.
The first two Calorie Reports, each the work of some 10-15 individuals, have both been well received. They have not been subjected to major criticisms by any of the hundreds of other expert nutritionists who have read and used them. There have however been criticisms of detail (see 5 a-h). The general method of approach, used by both committees, has been to set the requirements of a reference man and woman under well defined conditions and then to consider the variations introduced by such factors as climate, body weight, age, pregnancy and lactation. The requirements of children have been considered separately. The principle of the use of a reference man and woman has not been seriously challenged. I have not seen in print or heard in private conversation any suggestions that an alternative method of approach would give results which would be either scientifically more precise or more readily applied in practice. Any present day revision by a new Expert Committee would certainly use a reference man and woman.
Far and away the most important decision of the First Committee was to set the requirements of the Reference Man (aged 25, weight 65 kgs., living at a mean annual temperature of 10°C) at 3200 kcal/day and the Reference Woman (aged 25, weight 55 kgs., living at a mean annual temperature of 10°C) at 2300 kcal/day. The Second Committee endorsed this recommendation. They stated (p. 16) that for those comparable in size to the Reference Man and Woman "a range of energy expenditure between 2400 and 4000 kcal/day for men and between 1600 and 3000 for women would appear to include most human beings". There has been much fresh evidence in conformity with this generalization. It could perhaps be dignified as a 'Physiological Law'. There are, of course, some exceptions. Small groups of men, such as lumberjacks, arctic explorers and others, have been shown to expend energy at higher rates, but only for periods of time measured in weeks, or occasionally in months, but not in years. Large numbers of people may lead lives so sedentary as to fall below this range. They could hardly be described as 'normal' or 'healthy' (see below).
That the allowances for the Reference Man and Woman were put half way between these two extremes at 3200 and 2300 kcal/day respectively by the First Committee was no more than a sensible guess. Its justification is the fact that estimates of requirements based on these figures have been widely used by FAO and National Committees and have always appeared 'sensible'. At least they have produced no obvious absurdities. The Reference Man and Woman are further discussed in sections 4 and 5 (a).
FAO in their Annual Reports on the State of Food and Agriculture and their Three World Food Surveys, have set out numerous tables comparing calorie supplies with calorie needs for different countries, different regions and the whole world. These tables have been used for planning food policies for different countries and regions. The second report on Calorie Requirements is one of the main bases on which the careful planning of the Third World Food Survey rests.
The Third World Food Survey provides not only an estimate of the extent of undernutrition throughout the world, but also gives short-term and long-term targets for agricultural production for the various regions of the world. Clearly a great deal of work has been expended in drawing up these targets and, to the writer at least, they seem practical. Any alteration of estimates of calorie requirements would change these targets and lead inevitably to at least some temporary confusion. Estimates of calorie requirements should not be altered except for weighty reasons.
The future need of mankind for food depends in part on how society becomes organized. It will be determined to a considerable extent on the choice made by future generations on how they wish to spend their lives.
Until the eighteenth century the chief source of power available to mankind was muscle. Human muscles and animal muscles did the work of agriculture. Human muscles were also responsible for providing the energy needed for constructing both simple homes and the great palaces and cathedrals. They also made clothes and did all the domestic chores. Helped by domestic animals they were responsible for transporting men and materials from place to place. Wind- and water-mills were the only supplementary supplies of power and in practice their use was limited.
In the last 200 years the Industrial Revolution has made available increasing supplies of new sources of power. At first steam engines, then electrical engines and internal combustion engines came into use. Now atomic power is being developed rapidly in some countries. The immediate effect of the Industrial Revolution was paradoxically to increase the amount of human labour. In the middle of the nineteenth century men, women and children often worked regularly 60, 70 and even 80 hours a week in factories and mines. Homo sapiens was exploited and became homo laborans. Technical developments and a century of industrial legislation have reduced these hours of work. Disputes and arguments between contemporary trade unionists and industrialists are nowadays usually concerned with a figure around 40 hours of work a week. Further, much of this time is spent in operating the controls which regulate nonhuman supplies of power. In industrial societies "work" is involving less and less muscular effort. In consequence muscles need less fuel - less food.
It is almost certain that within one or two decades, in several countries, many industries will be working a 20 hour week. Housewives with a good home, modern electrical appliances and access to supplies of processed food can look forward to a similar short working week - when their children have reached school age. These factors raise in an acute form the question of how leisure is used. Older textbooks of physiology were concerned almost entirely with the energy requirements and food needs for work. It was the great contribution of the Second Calorie Committee to set out clearly that in many societies the 'non-occupational' or recreational component of the daily energy expenditure (or food requirement) was greater than the work component.
If the demise of homo laborans takes place in many parts of the world within the lifetime of our children, who will replace him and what will his calorie requirement be ?
Two possibilities need discussion. There are already signs of the presence of a new type of man and woman, homo sedentarius, who like to spend their new found leisure sitting in front of television sets or sitting at the wheel of an automobile and driving around the countrysides of the world. The existence of homo sedentarius in North America and Western Europe is now well documented. The present scales of calorie requirements provide more food than homo sedentarius needs. When they continue to eat in the manner of homo laborans, inevitably they become obese.
Alternatively the new citizens of the world may be largely homo sportivus. They will employ the new leisure in football, tennis, dancing, gardening, hiking, bicycling, climbing mountains and sailing boats, and in other active pastimes according to their inclinations, age and sex. I consider that the Second Calorie Committee's scales would prove adequate for homo sportivus in a mechanized and industrial society. There is already some evidence to show that this would be so.
The food needs of the world in the year 2,000 depend largely on the relative proportions of homo laborans, homo sedentarius and homo sportivus living at that time. Anyone can speculate. We most of us hope and work for the demise of homo laborans. My own preference is for the life and company of homo sportivus. Perhaps homo sedentarius is both an unhappy and unhealthy person. The scientific evidence that he is unhealthy is limited: I have helped to prepare a brief review (+) which has persuaded me that homo sedentarius is especially prone to those degenerative diseases (notably obesity and atherosclerosis) that appear to be increasing in prosperous societies. Especially important is the impression that these degenerative diseases are affecting more frequently men and women at an early age, when they should still be in the prime of life. I hope that governments at all levels will facilitate the growth of homo sportivus by providing the necessary education and facilities. Should homo laborans be replaced by homo sportivus, it is probable that the scales of the Second Calorie Committee will last for a long time. If, however, homo sedentarius continues to multiply as he appears to have done in many countries in the last decade, the present estimates of food requirements will prove to be excessive in many countries.
These are already practical problems in North America and in Europe. In countries which have only recently begun to develop modern industries, there must be a considerable interval before ti will be possible to discuss a 20 hour week.
The needs of the Reference Man and Woman were subdivided by the Second Calorie Committee to meet energy expenditure during a day in which 8 hours were spent at work, 8 hours in non-occupational activities and 8 hours in bed. This regular subdivision of the day was certainly characteristic of large numbers, perhaps the majority, of the working population in industrialized societies in 1956. It certainly does not apply to peasant farmers who form the overwhelming majority of the population in underdeveloped countries.
In all countries the work required of the peasant agriculturist is dependent on the season. At harvest always and at sowing and planting often, the peasants have to work long hours and there may be a serious shortage of labout. At other seasons there may be little or no work to do in the fields and agricultural unemployment may be widespread. Clark (ü) has provided an important review of the economic problems of the peasant agriculturists. He quotes from surveys in Africa and India giving figures for the times actually spent at work in the fields by farmers. These range from 855 to 1700 hours/year. They correspond to rates between 17 and 34 hours/week, though weekly figures have little significance. However, it is quite clear that the Indian or African farmer is often by no means fully occupied in his fields. Clark comments: "With us, a farmer or farm labourer performs his agricultural work, then has the remainder of his time for rest and recreation. An African or an Indian peasant, however, besides his agricultural duties, has to find some time during the year for repairing or rebuilding his house, making his shoes and furniture, and also performing a great many religious and civil duties. We should have in our minds these preferences (whether for good reasons or for bad) for not devoting too large a proportion of one's working year to agricultural duties". Perhaps the peasant agriculturists have no source of power beyond that of their own muscles and the muscles of their domestic animals. The Industrial Revolution has barely touched them. What its effect will be in the future on their manner of life, rates of energy expenditure and needs for food anybody can guess. The traveller can easily observe that the amenities provided by the motor bus and radio entertainment are greatly appreciated. Perhaps the life of homo sedentarius will have its appeal. However football is now almost ubiquitous. Homo sportivus will also be the aim of many.
(+) Davies, C.T.M., Drysdale, H.C. and Passmore, R. (1963) Lancet, 2, p. 930-932
(ü) Clark, C. (1963) in Food Supplies and Population Growth, Edinburgh, Oliver and Boyd. Proceedings of a symposium also published in J. of Roy. Stat. Soc. A (1962) 125, part 3.
In applying the allowances for the Reference Man and Woman to peasant agriculturists, the Second Calorie Committee were only guessing and, at the time of writing, a new Committee could do no better. However, the use of the figures for calculating national requirements has produced no absurdities in countries where most of the working population are peasant farmers. Estimates of calorie requirements agree on the whole reasonably well with measurements of calorie intakes in dietary surveys where there is no clinical evidence of undernutrition. Thus Nicol (+) estimated the intake of calories in 7 groups of Nigerian peasants employed in different types of agriculture. Each group was surveyed at three different seasons of the year. The mean calorie intakes for each group of men, expressed as a percentage of the FAO estimate of requirement, were 116, 94, 120, 104, 101, 85 and 94 (average 102): or for each group of women the figures were 143, 68, 102, 129, 95, 89 and 95 (average 103). These surveys covered 206 men and 242 women. The results suggest that the present standards of requirements are applicable at least to Nigerian peasants.
It is possible that both in industrialized and peasant communities men and women may be leading more sedentary lives than is indicated by the schemes set out for the Reference Man and Woman. If so, then calorie requirements have been overestimated. From this it would follow that the Third World Food Survey has overestimated the extent of undernutrition in those countries where there are large numbers of peasant farmers and underestimated the amount of food wasted in prosperous countries. It would also have overestimated future food needs. My guess is that each of these estimates is out (very slightly) along the line indicated. There is no evidence that would enable a new Committee to make more precise estimates of requirements.
For the future, calorie needs depend on the kind of lives men choose to lead. If it be accepted that an active life is better and healthier than a sedentary life, then the present allowances set out what is required for a healthy population.
Measurements of the energy cost of a great variety of activities, both occupational and non-occupational, have been made for many years. Passmore and Durnin(ü) put together much of the earlier literature in a review which was available to the Second Calorie Committee. Since then much new data has been published and copies of the review can no longer be obtained. Durnin and I plan to publish shortly a new review.
(+) Nicol, B.M. (1959) Brit. J. Nutr. 13, 293.
(ü) Passmore, R. and Durnin, J.V.G.A. (1955) Physiol. Rev., 35, 80.
A real difficulty is the classification and grading of industrial work. The Second Calorie Committee referred to Christensen's (+) classification, based on observations in the Swedish steel industry. This is set out in Table 1. This classification appeals to physiologists. Heavy work is defined as work above 7.5 kcal/min., which corresponds to rates of oxygen utilization around 1500 ml/min. This is about the upper limit of human aerobic capacity for work. Heavy work, so defined, is thus partially anaerobic and involves a significant oxygen debt and the accumulation of lactic acid in the blood and tissues. Such a classification would not appeal to trade unionists, who like to see much less arduous effort designated as 'heavy work'. Table 1 also shows the rates of energy expenditure, determined by Brown and Crowden (++), corresponding to the various grades of work, as defined for use in a large industrial estate near London. Banerjee (+++), in a review 'Studies in Energy Metabolism' quotes Indian definitions: light work up to 3.0 kcal/kg/hr, moderate work 3.0 - 5.0 kcal/kg/hr. and heavy work over 5.0 kcal/kg/hr. For a man weighing 65 kg., this scale corresponds closely to the English one described by Brown and Crowden. Many other scales of grading are in use in industry throughout the world. It would be nice if everyone used the same language in talking about the intensity of work, but there would be immense practical difficulties in achieving uniformity, which would have to be acceptable to trade unionists and industrialists throughout the world.
If these are combined with measurements of energy expenditure rates for the different activities, overall values of energy expenditure over a period of days (or even weeks) can be calculated. This provides the best theoretical method for assessing the calorie needs of a group. The Second Calorie Committee had available the data from a few surveys in Great Britain, which covered the whole of the daily life of various groups for a period of one week. It was on the basis of these results that the 'non-occupational' activities of the Reference Man were set at 1500 kcal/day. Since then new surveys have been carried out, but not on a large scale. Harries, Hobson and Hollingsworth (ü) have put together a summary of all the surveys in Great Britain (Table 2, which also includes results of individual dietary surveys). They have covered 270 individuals in 19 groups. The collection of this data has cost much effort, time and expense. The information is quite inadequate to allow conclusions about the overall food requirements of the country. However a study of the data shows that the FAO allowances predict the requirements with reasonable accuracy.
(+) Christensen, E.H. (1953) In Ergonomics Society Symposium on Fatigue, p. 93, ed. W.F. Floyd and A.T. Welford, London: Lewis.
(++) Brown, J.R. and Crowden, G.P. (1963). Brit. J. Indust. Med. 20, 277.
(+++) Banerjee, S. (1962) Indian Cown. Med. Res., Spec. Rep. Ser. No. 43.
(ü) Harries, J.M., Hobson, E.A. and Hollingsworth, D.F. (1962). Proc. Nutr. Soc. 21, 157.
Banerjee, in the paper already referred to, summarizes the findings in four surveys of rates of energy expenditure in India. From his figures, it is possible to calculate the FAO estimates of requirements for each group. Measured rates of energy expenditure expressed as a percentage of the FAO estimate of requirements were 74 for the male laboratory workers, 78 for the college girls, 130 for the workers in a textile mill and 209 for Calcutta rickshaw pullers. From these results it may be concluded that the laboratory workers and college girls lived sedentary lives with little active recreation and that the work in a textile mill is often heavy. We can salute the Calcutta rickshaw man as one of the hardest workers in the world. These figures provide quantitative confirmation of the impressions of casual observers of the Indian scene. A detailed study of the daily rates of energy expenditure in textile workers in Coimbatore and in Ahmedabad has been made by P.S.V. Ramanamurthy of the Nutrition Research Laboratories (Hyderabad). A preliminary report is available (+) but the full results have not been published. Inasmuch as there is no data on the activities of the peasant farmers, it is impossible to tell how accurately the FAO estimates predict the present food needs of India.
Energy expenditure surveys have been carried out in other countries, but mostly on a small scale and usually on members of the Armed Forces or other special groups.
Activity studies have proved a useful and practical means of determining the calorie requirements of small and homogeneous groups of men and women. In a limited way they have provided some general support for the present FAO estimates of requirements. It is to be hoped that such studies will be continued on an increasing scale. The cumulative data will provide useful pointers to the overall needs of countries.
The text of this second section of the second Committee's report and the related sections on Fat Content and its Significance and on A simple formula for relating body weight and calorie requirements seem a little outdated in 1963. Although they contain nothing incorrect, I am sure that a new committee would wish to rewrite them. The subject of Body Composition has been explored energetically in the last 10 years. A symposium on this lasting a week was held in New York in 1963 and the proceedings ran to 1000 pages (New York Academy of Sciences, 1963, 110). New methods of deriving values of the 'cell mass' of the body are described and this appears to be more closely correlated to basal metabolism than to surface area. Methods of estimating body fat have also been greatly improved. I attended this symposium and have studied the published proceedings carefully. There is no new knowledge which would allow any improvement on the means of relating energy requirement and body weight other than the empirical formulae given in the second report, viz:-
(+) Patwardhan, V.N. (1959). Annual Report of the Nutrition Research Laboratories, Hyderabad.
|E = 152 W 0.73 (men)|
|E = 123 W 0.73 (women)|
|E = 815 + 36.6 W (men)|
|E = 580 + 31.1 W (women)|
The observation (+) based on diet surveys mostly in Scotland, that big people seem on average to eat no more than small people is quite out of line with orthodox physiological concepts. Our suggested explanation is that big people must be less physically active than small people. Weight may have a sedative action. This finding needs confirmation and its significance has to be explored much further before there could be any justification for changing recommendations.
The second Calorie Committee modified the recommendations of the first on the reduction in needs with advancing age. The changes were based on experience in applying the earlier report and general considerations rather than on research data. Old age comes on at very different times. Some are still active both in body and mind after passing their eightieth birthday; others are infirm and age soon after fifty. Data for making generalizations are not available, nor can they easily be made available. Surveys on elderly men (++) and women (+++) have been made in Glasgow. For 4 groups numbering 9, 12, 12 and 17 individuals, the mean values found for weekly rates of energy expenditure were respectively 108, 100, 108 and 103 per cent of the FAO estimates of requirements. The figures obtained at the cost of much time and money, indicate that the FAO estimates predicted with reasonable accuracy the needs of 48 elderly people in Glasgow. They may justify the conclusion that the estimates were satisfactory for the many thousands of old folk in that city. Surveys on this scale do not provide justification for conclusions with world-wide applications. Until numerous surveys in several parts of the world have shown that the present estimates of the needs of old people are unrealistic, there is no indication for change.
Most of us are aware that a cold day sharpens the appetite and that on a very hot day there may be little desire to eat. The food eaten by U.S. and Canadian soldiers stationed in various parts of the world during World War II was measured by Johnson and Kark. A close correlation was found between observed voluntary intake and the mean external temperature (taken as a measure of climatic environment). Impressed by this finding the first Calorie Committee recommended that all allowances should be increased by 5 per cent for every 10° C below the reference temperature and reduced by 5 per cent for every 10° C above the reference temperature.
(+) Thomson, A.M., Billewicz, W.S. and Passmore, R. (1961) Lancet 1, 1027.
(++) Durnin, J.V.G.A. et al (1961) Brit. J. Nutr. 15, 587.
(+++) Durnin, J.V.G.A. et al (1961) Brit. J. Nutr. 15, 499.
The Second Committee endorsed this reduction of requirements in hot climates, but reduced the extra allowance in cold climates from 5 to 3 per cent. They considered that in cold climates men and women were but little exposed to the cold, generally living and working in homes, offices and factories maintained artificially at a temperate climate.
Two physiological facts have to be considered in any further adjustment of these allowances for climate. First the basal metabolic rate (BMR) is determined in part by climate. This has been known for a long time. There is no evidence that the different races have different BMR. However, residents in the tropics, whatever their race and place of birth, usually have a BMR significantly below the standards set up in North America and in North West Europe.
Secondly, during the decade 1950-1960, the U.S. Armed Forces have carried out a long series of carefully controlled studies of men living and working under extreme environmental conditions. Many reports have been published, but mostly as service documents, not readily found in libraries. These have been ably summarized by Consolazio (+). As this work may not be well known, conclusions are given in full:
"A. Extremely Cold Environments
Newer evidence collected during the past few years indicates that there is no basis to the conception that the energy requirements of humans (at a given activity level) are increased in a cold environment, except under the following conditions when the metabolic rate is also increased: (a) in the unprotected or clean-shaven animal, (b) in the nude or inadequately clothed human, (c) when a considerable time is spent in the cold to make an individual shiver or to cause non-perceptible shivering (muscle tone or muscle activity), (d) in the wearing of extra-heavy clothing or foot-gear that would impose a resistance to body movement, or (e) in any other unusual condition that would increase the metabolic rate.
The data suggest that the energy requirements of men living and working in a cold environment are not increased, provided the men are adequately clothed, except for the 2-5 per cent increase in metabolic rate due to the 'hobbling' effect of the heavy clothing. It is felt that the energy requirements, as in a temperate environment, are primarily a function of body weight."B. Extremely Hot Environments
In view of the new evidence presented during the past few years, there is a strong suggestion that the energy requirements are increased in men living and working in extreme heat. This, of course, excluded the individual living in an air-conditioned atmosphere. These studies show that there is a significant increase in the metabolic rate of all daily physical activities, when comparing an extremely hot environment to a temperate environment. Significant increases were also observed in the food intake, in the sweat rates and in body temperature, when comparing the same environments.
(+) Consolazio, F. (1963) World Rev. Nutr. 4, 53.
These increased requirements are probably due to the increased heat load imposed on the body by solar radiation and the extreme heat. The increased requirements, in all likelihood, are a combination of increased action by blood in heat transport, increased action of the sweat glands, increased calorie loss due to sweat vaporization, plus the increase in metabolic rate due to the elevation in body temperature. It has been calculated that a degree centigrade rise in environmental temperature over 25° C is equivalent to 105 Cal., or 1.4 cal/kg of body weight/deg.C."
These experiments were planned to test the effects of extreme heat on specific work schedules, as might be carried out by men in the armed forces for a short period. The conclusions drawn from them cannot be applied to large populations living and working in tropical countries. The relation between decreasing food intake and increasing environmental temperature, demonstrated by Johnson and Kark, probably arises because as it gets hotter, physical activities become progressively reduced, both at work and during recreation. If people sit around more in the heat, reduced calorie allowances are justified. At present we have no sound evidence on which to decide how big these reductions should be. There is need for surveys on people following similar occupations but under very different climatic conditions (see section 5h). Until such surveys have been carried out and we know more about how climate determines activities, there is in my opinion no evidence available to justify changes in the present recommendations for requirements in hot climates.
A new Calorie Committee would almost certainly go further than the Second Committee and out out altogether the extra allowance for cold. This would have very little effect in the calculations on which the Third World Food Survey is based. Canada has for many years excluded this allowance in calculating her food needs.
International data are scarce and both previous Calorie Committees have recommended for general use the American NRC scale. Since the Second Committee met, all the data for dietary surveys of USA children have been brought together; these involve data on many thousands of children. A new scale of requirements has been drawn up based on these surveys and has been sent to FAO by Dr. J. Mayer. This scale is compared below with the present FAO estimate (taken from the previous American scale).
|Suggested New Scale|
|7-9||2,100||7 - 10||2,300|
|7-9||2,100||7 - 9||2,000|
The suggested new scale gives a slightly higher allowance at the early age group and lower allowances between the ages of 16-19. Its adoption would reduce estimates of national requirements, but by an amount so small (less than 2 per cent) as to be of little significance.
More important is the fact that these figures are likely to be used in drawing up dietary schedules for young people in boarding schools, training centres for the armed services, remand homes, etc. Physical activity in such institutions is liable to be great. It would seem unrealistic to measure their needs against those of American teenagers, mostly living at home - often with the free use of Father's cars. There is now much evidence that many American young people lead too sedentary a life, so much so that juvenile obesity is becoming an important medical problem.
The adoption of the suggested new scale would lead to the absurdity that a young man and a young woman of 19 years would be allowed less than a man or woman of 25 years.
The allowances for children in the Second Calorie Report are generous. They provide for children who lead an active life with full opportunity for sport and play. This is as it should be. I can see no valid reason for curtailment.
The main findings, as set out by the Second Committee, remain unchanged. New knowledge is available about how individuals who consume regularly more than 100 g/day of alcohol dispose of the excess by metabolic pathways not involving alcohol dehydrogenase. (+)
The recommendation that "calories from alcohol should now be included in food balance sheets in the same way as the calories derived from the protein, fat, carbohydrate, in the various food consumed" has, I understand, been seldom carried out. This is because in most countries figures for the supply of alcohol beverages cannot be readily obtained.
There are figures available for some countries. In France, for instance, in 1959/60 the supplies of beer and wine were 101 and 369 g/head/day respectively. This would correspond to about 290 kcal/head/day. In Italy in 1960/61 the supply of alcoholic beverages indicates that these provided about 220 kcal/head/day. These figures are not usually included in calorie balance sheets. In France this omission means that calorie supplies have been underestimated by about 10 per cent. The figure for the underestimate is not likely to be higher in any other country; in many it may be about 5 per cent. It would probably be impractical to alter present custom in the immediate future. It is, however, important to remember this source of error in food balance sheets.
(+) Tremolières, J. and Carre, L. (1960) C.R. Acad. Sciences, 251, 2785-2787.
All estimates of calorie requirements based on physiological evidence are given in terms of calories needed "in the stomach". Estimates of calorie supplies are at "retail level"; these include corrections for estimates of losses during the transport, storage, manufacture and distribution of foods. Estimates of physiological requirements and supplies at "retail level" can only be compared if the physiological requirements are increased by a factor, which allows for wastage in the kitchen and in the dining room.
This factor varies greatly. A hungry person will lick his plate clean and when there is a real shortage of food, the factor is probably less than 1 per cent. In prosperous societies it is much higher. Recent surveys have shown that more than 30 per cent of the food going to the wards in certain British hospitals is wasted. A study of the garbage cans outside the homes of the wealthy in the USA and elsewhere would probably indicate that wastage was even higher.
The Second Calorie Committee recommended that further studies of wastage of food should be made and several correspondents have written to FAO urging the necessity for this. The extent to which food is wasted in the homes and institutions of a country may be of local interest and perhaps of great importance. I cannot see that it helps to set out standards. The second Calorie Committee stated that "the available data indicate that in most countries edible food waste does not exceed 10 per cent of the calories at the retail level". It is implied (but not specifically stated) that this is a reasonable figure; it has become the custom to use this figure for correcting physiological standards for comparison with retail supplies in many countries. To a male physiologist unversed in these matters, this seems sensible. It would be of little value to know exactly how low the figure may be driven by poverty or how high it may sometimes rise under the influence of wealth and inefficiency. I would be interested to know the losses of food in selected homes and institutions in various countries, run by competent housewives and catering officers, whose husbands and boards of management provide adequate, but not excessive money for the purchase of food. It does seem important to know if a 10 per cent allowance for wastage is adequate, when there is domestic competence and no poverty.
The second Calorie Committee indicated broad outlines for future investigations. These involved for the most part field surveys either of energy expenditure or of energy intakes in groups of individuals of different ages in varying environments. As already indicated, such surveys have been carried out notably in Scotland, India, Nigeria and in the U.S. Armed Forces, and these have in general confirmed the previous estimates of requirements. However, they have been on so small a scale that they do not provide a firm scientific basis for the estimates, which still in large part remain 'intelligent guesses'.
Field surveys are usually concerned with random samples of people living typical contemporary lives. Provided that there has been no obvious ill health and poverty, the results have in the past been used to set and check standards. Standards may be used as targets, as in the Third World Food Survey. This involves the making of value judgements. For what kind of life are we setting standards ? The ancient Greek philosophers, from whom we draw so much of our ethical values, scorned physical work. They were able to do this, because they lived in a society which tolerated human slavery. We also will be in a position to scorn work, if the techniques of physical sciences are intelligently applied. A working life of 20 hours a week, or 1000 hours a year is, as already discussed, a legitimate target. It is no longer a 'pipe-dream'. This figure is equivalent to 12 per cent of the total time in a year of the life of a working man or woman. If this is an acceptable aim for a good life for future generations, then clearly in setting standards we must be concerned much more with requirements for leisure than with those for work.
Surveys will be more valuable for setting standards for the future if they are carried out not on the average man leading a typical life of to-day, but on people whose health and income enables them to lead a full life, enjoying the legitimate recreations of their society. I would like to see a series of surveys carried out on groups with different cultures and living in very different climates. Attention to adolescents and the elderly would be most important.
The carrying out of these surveys would be expensive and would need organization on a large scale and co-ordination. Much of the work could only be done by local research workers, backed by national research bodies, but the help of international agencies would be essential. This would be a legitimate task for the nutrition divisions of FAO and WHO.
There are field workers whose experience would allow them to judge whether this proposal would be practical. Some estimate of the scale of the investigations and of the needs for money and scientific manpower is required. I hope that the present report has provided evidence to justify the recommendation that FAO and WHO call together a small group of nutritional field workers to consider the practicability of organising a series of surveys of energy expenditure and food intake of groups of healthy individuals who are not prevented either by ill health or poverty from leading a full and active life. The surveys should be carried out in parts of the world where both the culture of the people and the climate differ greatly. Special attention should be paid to adolescents and the elderly.
The reports of the two Calorie Committees form numbers 5 and 15 in the series of FAO Nutritional Studies. The monographs in this series appear to fulfil two functions. First they provide working material on which the FAO Secretariat, other UN agencies, national governments and various organizations can plan and administer practical nutrition programs. Secondly they provide education material, which University staff and other teachers can use for giving instruction in the nutritional sciences to classes with widely different interests and background. The authors of the monographs have obviously had both these aims in mind, but in varying degree. As a University teacher, I have given several of the monographs to students for preparing material for tutorials, seminars, etc.. In general I have found the earlier monographs excellent, but am not so confident about the later ones. For instance, No. 16 on Protein Requirements has caused much confusion to all but the best students.
It is difficult to tell how much the monographs are used for teaching. The first printing in 1957 of the English edition of No. 15 on Calorie Requirements was 3000. This was soon disposed of (543 by sale and 2457 as complimentary copies). There was a reprint in 1959 of 2000 copies (of these 1268 have been sold, 411 presented and 121 remain). Clearly there has been a considerable demand. With the reprint all but exhausted some action will soon be imperative.
For use in the FAO Secretariat and other offices, the recommendations of the second Calorie Committee could be easily reproduced on a few stencil sheets without the accompanying text.
As a University teacher, I would like to suggest that the text of the Calorie Report be rewritten specifically for students. The text of the reports on Protein, Calcium and Vitamin Requirements could be similarly treated. If these were bound together they would form a book, which might be entitled "The Physiological Basis of Nutrition - an International Presentation". Such a book would, I am confident, find many readers in all parts of the world. My suggestion is that it would be based on the reports of the Expert Committees, but that it would not be written by the Committees. Writing for students is a long and difficult task for which the Committees have not the time. The actual writing could be done by one or more members of the Secretariat of FAO and WHO, with the assistance of a consultant who was a full-time teacher of physiology (but not necessarily a specialist in nutrition).
ENERGY EXPENDITURE RATES IN RELATION TO INTENSITY
OF MUSCULAR WORK
A. Christensen's classification based
on observations in the Swedish steel
Less than 2.5 kcal/min.
2.5 - 4.9 " "
5.0 - 7.4 " "
7.5 - 9.9 " "
More than 10.0 " "
B. The Slough Scale used in light industry in England with energy expenditure rates measured by Brown and Crowden.
1.1 - 2.0 kcal/min.
2.0 - 3.0 " "
Light to moderate
2.0 - 5.0 " "
3.0 - 5.0 " "
Moderate to heavy
3.0 - 8.0 " "
5.0 - 8.0 " "
Heavy to very heavy
5.0 - 8.0+ " "
TABLE 2A. VARIATIONS IN ENERGY EXPENDITURE
|Source||No. of subjects||Period of survey (days)||Information about subjects||Mean daily value for all subjects (kcal)||Minimum daily mean for any subject over the period (kcal)||Maximum daily mean for any subject over the period (kcal)||Standard deviation of subject means (kcal)||
Coefficient of variation of subject means (%)
|Happold (1945)||29||-||Medical students /?/|
|20||-||Medical students /?/|
|Edholm, Fletcher, Widdowson and McCance (1955)||6||14||Intermediate cadets||3,488||
|Garry, Passmore, Warnock and Durnin (1955)||10||7||Clerks||2,800||2,330||3,290||353||12.6|
|Adam, Best, Edholm and Woolf (1957)||Army troops:|
|Booyens and McCance (1957)||4||7 or||Scientific workers: /?/||2,797||1,933||3,897||597||21.3|
|Durnin, Blake and Brockway (1957)||12||7||Housewives||2,090||1,764||2,320||164||7.8|
|Adam, Best, Edholm, Fletcher, Lewis and Woolf (1958)||29||21||Army recruits||3,774||2,868||4,765||444||11.8|
|Adam, Best, Edholm, Goldsmith, Gordon, Lewis and Woolf (1959)||5||18||Army recruits||3,764||3,499||4,105||251||6.7|
|Durnin, Blake, Brockway and Drury (1961)||15||7||Elderly women||1,991||1,492||2,409||251||12.6|
|Durnin, Blake, Allan, Shaw and Blair (1961)||20||7||Elderly women||2,290||1,795||2,962||299||13.1|
|Durnin, Blake, Allan, Shaw, Wilson, Blair and Yuill (1961)||33||7||Elderly industrial workers /?/||2,957||2,185||3,958||486||16.4|
|Blake, Durnin, Aitken, Caves, and Yuill (1962, in preparation)||9||7||Elderly retired /?/||2,327||1,754||2,811||322||13.8|
TABLE 2B. VARIATIONS IN ENERGY INTAKE: ADULT MALES
|Source||No. of subjects||Period of survey (days)||Information about subjects||Mean daily value for all subjects (kcal)||Minimum daily mean for any subject over the period (kcal)||Maximum daily mean for any subject over the period (kcal)||Standard deviation of subject means (kcal)||Coefficient of variation of subject means (%)|
|Widdowson (1936)||63||7||Various, middle class||3,067||1,772||4,955||714||23.3|
|Happold (1945)||29||Medical students: November||2,674||--||--||695||26.0|
|Pyke, Harrison, Holmes and Chamberlain (1947)||12||7||Active aged (in small instit.)||2,160||2,050||2,251||66||3.1|
|12||7||Infirm aged (in large instit.)||2,069||1,903||2,272||100||4.8|
|Bransby, Daubney and King (1948-9b)
|Kitchin, Passmore, Pyke and Warnock (1949)||61||7||Students: at home||3,040||2,140||4,690||580||19.1|
|Ministry of Food (1949, unpubl.)||74||7||Industrial workers||3,407||2,108||4,470||511||15.0|
|Bransby and Osborne (1953)||125||7||Elderly||2,096||< 1,000||> 3,000||503||24.0|
|Bransby (1954)||152||7||Industrial workers||3,549||--||--||620||17.5|
|Edholm, Fletcher, Widdowson and McCance (1955)||6||14||Intermediate cadets||3,524||2,917||4,222||407||11.5|
|Garry, Passmore, Warnock and Durnin (1955)||19||7||Miners||4,030||3,090||5,410||557||13.8|
|Adam, Best, Edholm and Woolf (1957)||13||4||Army troops: exercise I||3,502||2,998||4,130||370||10.6|
|Booyens and McCance (1957)||4||7-14||Scientific workers||2,868||2,133||4,412||676||23.6|
|Adam, Best, Edholm, Fletcher, Lewis and Woolf (1958)||58||21||Army recruits||3,818||2,027||5,333||625||16.4|
|Adam, Best, Edholm, Goldsmith, Gordon, Lewis and Woolf (1959)||6||18||Army recruits||4,077||3,459||4,563||415||10.1|
|Ccok and Wilson (1960, private communication)||561||7||Students||2,984||--||--||507||17.0|
|Heady, Marr and Morris (1961unp.)||118||7||Bank officials||2,851||1,749||4,055||430||15.1|
|Durnin, Blake, Allan, Shaw, Wilson, Blair and Yuill (1961)||33||7||Elderly industrial workers||2,993||2,119||3,963||376||12.6|
|Blake, Durnin, Aitken, Caves and Yuill (1962, in preparat.)||9||7||Elderly retired||2,054||1,406||2,606||398||19.4|
TABLE 2C. VARIATIONS IN ENERGY INTAKE: ADULT FEMALES
|Source||No. of subjects||Period of survey (days)||Information about subjects||Mean daily value for all subjects (kcal)||Minimum daily mean for any subject over the period (kcal)||Maximum daily mean for any subject over the period (kcal)||Standard deviation of subject means (kcal)||Coefficient of variation of subject means (%)|
|Widdowson and McCance (1936)||63||7||Various, middle class||2,187||1,453||3,110||388||17.7|
|Widdowson and Alington (1941)||57||7||Various, middle class||2,137||--||--||420||19.7|
|Happold (1945)||20||Medical students: November||2,348||--||--||449||19.1|
|Pyke, Harrison, Holmes and Chamberlain (1947)||9||7||Aged: at home||1,409||1,034||2,313||369||26.2|
|12||7||in large institution||1,580||1,252||1,717||129||8.2|
|Bransby, Daubney and King (1948-9b)||18||3||(By calculation)||1,908||1,360||2,843||352||18.4|
|Kitchin, Passmore, Pyke and Warnock (1949)||71||7||Students: at home||2,180||1,450||3,160||370||17.0|
|Bransby and Osborne (1953)||178||7||Elderly||1,746||< 1,000||> 3,000||427||24.5|
|Booyens and McCance (1957)||2||7-14||Scientific workers||2,007||1,063||2,471||--||--|
|Durnin, Blake and Brockway (1957)||12||7||Housewives||2,100||1,593||2,435||245||11.7|
|Cook and Wilson (1960, private communication||205||7||Students||2,429||--||--||462||19.0|
|Durnin, Blake, Brockway and Drury (1961)||17||7||Elderly, living alone||1,894||1,107||2,283||299||15.8|
|Durnin, Blake, Allan, Shaw and Blair (1961)||21||7||Elderly, at home||1,944||1,243||2,886||404||20.8|
|Copping (1962, unpublished)||82||7||Students||2,157||1,340||4,014||464||21.5|
|McCance, Widdowson and Verdon-Roe (1938)||120||7||Various||2,347||1,163||3,522||497||21.2|
|Roscoe and McKay (1946)||35||7||2,550||1,660||3,650||473||18.5|
Social class: I and II
|279||7||IV and V||2,354||--||--||513||21.8|
|Thomson (1958, unpublished)||489||7||All the above classes||2,449||1,126||4,152||503||20.5|