different foods. Our experience at the Phipps Institute has been that housewives vary tremendously in their purchasing abilities; one woman, for instance, for every ten cents, would get food equivalent to fifteen hundred calories, another would get only nine hundred. In other words, there was a difference of almost 40 per cent between the purchasing power of two women.

In some of the work that we have done in connection with tuberculosis classes, we watched more or less closely the amount of food the patients were getting. It was necessary, in almost every instance, to show them the kinds and amounts of food needed. If there were available four or five dollars a week for food in a family of five-I am quoting figures for six years ago-it became necessary in nearly every instance to show them exactly how they should spend those four or five dollars to get the food that would give them the best returns.

The only way we have of controlling the amount of food we are giving to an individual and determining whether that individual is on a subnormal diet or not, is by the caloric method. I want it understood, of course, that the calory does not mean everything. We have to take into consideration the preparation of the food and very often, the service of the food and, in addition, to keep in mind, the use of those foodstuffs which furnish the so-called vitamines. But the caloric method is necessary as a means of determining whether the individual is on a subnormal diet, or whether, perhaps, he is being overfed, as many are. In one school which was investigated, it was found that the boys were each receiving about 5,500 calories daily and in addition were getting about 500 more outside in the form of candy. In other words, they were tremendously overfed.

The difficulty with the caloric method has been that lay people as a whole have very little conception of what is meant by a calory; and it is undoubtedly true that many physicians have a very hazy idea of what is meant if you say that an individual should have 2,200 or 3,000 calories a day. The great trouble with the caloric method has been the difficulty of translating the values in intelligible form to the individual who knows nothing about them. One of the difficulties has been that it is a tremendous tax on the memory to recall that so many grams of a certain amount of food equal 135 calories, and so many grams of another kind of food equal 40 calories.

What I believe to have been a market advance in the introduction of the caloric method was a suggestion first made by Dr. Irving Fisher, by which you use a common unit of 100. The next advance in this line was made by Dr. William Emerson, of Boston, who translated these 100 calories into perfectly familiar terms so that even the most ignorant housewife could understand. He has reduced them, for instance, to teaspoonfuls, cupfuls and so on-a teaspoonful of a given amount of food equals a hundred calories, so in that way the values could be very easily followed. He has had an exhibit prepared on these lines which he has used with extraordinarily good effect in the teaching of dietetics to delicate children. In this way he has been able to teach children, of even seven or eight years of age, how many calories they have taken a day and how many more they need to make up their quota. It is not so difficult to teach even the individual with a very slight amount of education what you mean when you say that he must have 2,200 or 2,400 calories of food per day when this is translated into familiar measurements. I have had one of these food exhibits made because it visualizes these values and enables one to learn more in a few minutes than any amount of talking would do concerning caloric feeding.

For instance, it does not take very long to remember that approximately a quart of bouillon made of the very best meat you can get is 100 calories, and you can contrast that with two tablespoonfuls of lima beans, which have a food value of 100 calories. The banana, equaling 100 calories, is one of the easiest articles of diet to get, is always on the market, and has recently been shown to be practically the equivalent of the potato. It can be eaten as almost the sole and only diet. The chief difficulty with the banana is that so often it is sold green, or partially so. One roll equals 100 calories; one pat of butter equals 100 calories; four of the ordinary Uneeda biscuits equal 100 calories; the lean portion of one lamb chop equals 100 calories; twelve double peanuts equal 100 calories; a piece of fish about the size of the palm of the hand equals 100 calories; a teaspoonful of peanut butter equals 100 calories; and so you can go through the whole list, reducing the commoner foodstuffs to a basis that anybody can understand. Extreme accuracy is not claimed for this plan but it does serve to give a fairly clear idea of what the individual should receive.

I used this method a part of last year with medical students and their own testimony was that they were able to get a clearer idea in fifteen minutes as to what was meant by caloric feeding by being able to visualize the articles, than they were by reading pages and pages of tabulations showing that so many grams of one thing equaled so many calories, and so many grams of something else equaled so many more calories. I intend to use the method this winter with dispensary patients to find out, in the first place, approximately how much food they are getting. It has been our experience that many of the patients who come to Phipps Institute are getting food which amounts to but 1,200, 1,500 or 1,800 calories when their disease demands that they should be getting about twice that amount; and quite as often as not you will find that their deficient dietary is not a result of the fact that they have not money enough to get the food, but because they are not purchasing the right kinds of food.

Whether a better method than this one can be devised for the teaching of dietetics among people who have no knowledge whatever of food values, I do not know. I do know this, that prior to my seeing this exhibit, I had a very poor idea as to what my daily food consumption was. I had not the slightest idea whether I was getting 1,500 or 3,000 calories, but with this method I can compute it with a fair degree of accuracy.

A GUIDE TO THE NATION'S DIETARY NEEDS

BY HELEN W. ATWATER,

Specialist in House Economics, States Relations Service, United States Department of Agriculture.

There are many popular theories current regarding the food habits and customs of different nations and regions and even more theories as to how those habits and customs might be changed to the benefit of mankind, but to a large extent these are based on inadequate observation, often merely on personal impressions, or even on the somewhat prejudiced opinions of the food faddist or the commercial exploiter. Evidently if we are to say with anything like accuracy how the nation can best be fed, we must have more definite

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information as to what it needs and what it habitually uses. are far from knowing as much as we should on either of these points, but the work of physiologists, chemists and statisticians taken together has done much toward starting us toward a real understanding of dietary needs.

During the last fifty years, our knowledge of human nutrition has developed into a well-ordered science, and as the combined result of clinical study, laboratory investigation and accurate observation of the diets normally chosen by persons living under different conditions, students of nutrition are now fairly well agreed as to the general food requirements of normal men, women and children. Our knowledge is rapidly increasing regarding the part played in the body by the different mineral matters, different types of protein, and the little known but apparently important growth-determining and body-regulating substances and as a consequence our ideas as to the special values of different kinds of food are slowly changing.

But while doctors still disagree as to the exact number of grams of protein a man should consume a day to build and repair his body tissues or exactly how we should reckon the calories of energy needed by the various members of a family, the great majority are now willing to adopt as a working hypothesis a daily requirement of from ninety to one hundred grams of protein for a one hundred and fiftypound man at full vigor, with 3,000 calories of energy if he does a moderate amount of muscular work. Certain factors are also generally accepted by means of which this standard can be changed to express the requirements of persons of different age, sex and muscular activities. The energy requirements of a man at severe muscular work, for example, are reckoned as two-tenths greater than that of one at moderate muscular work, and that of a woman as eight-tenths of that of a man of corresponding muscular activity. In the light of our present limited knowledge of the rôles played by different food constituents, it is generally considered safest to obtain the required protein and energy from a mixed diet in which the protein foods (i.e. meats, fish, dairy products, eggs, dried legumes, etc.), cereals, fruits and vegetables all appear with enough fats and sugars to render the diet palatable.

Exactly how much of each type of food should be included daily or even weekly, few would care to say. In practical menu making,

this is usually decided by the amount of money one has to spend on food; but the food groups should all appear reasonably often, and milk should always be provided for the use of children. Such a diet seems to correspond with the food habits most common in this country. Among the very poor, especially in large cities and in seasons of high prices, the total amount of food used is probably dangerously inadequate; and among special groups of our population, for instance in certain mountain regions of the southeastern states, there is evidence that the variety of food materials used is too restricted for safety; but taking the country over, we probably err on the side of abundance rather than scarcity. At any rate this is the condition shown by accurate studies of family dietaries that have hitherto been made in different sections of the country.

If we accept the standard quoted as a safe measure of food requirements, it should be a simple matter to calculate the food requirements of the nation. The census reports give the number of men, women and children of different ages and a fairly good indication of their occupations and probable muscular activity. Applying the factors previously referred to with these figures we could work out the total annual protein and energy requirements of the nation and the average requirements per capita per day. Going a step further, it would seem an equally simple matter to compare this theoretical national requirement with the total food consumed, and to tell at once how we could safely change our food consumption in a time of food shortage or national emergency. This is exactly what was attempted in Germany by the so-called Eltzbacher Commission and in England both by Thompson and by the Committee of the Royal Society in their reports on the Food Supply of the United Kingdom. It may be interesting to note in passing that both British reports used the American dietary factors and tables of composition of food materials originally worked out by Atwater and his associates and slightly revised by his successor, Langworthy, in the United States Department of Agriculture publications-a pleasant instance of the help American science has given to our allies.

Unfortunately, such calculations are open to two objections, which the practical experience of the foreign food control authorities has found to be well-founded. First, there are no figures from which the total food consumption can be calculated with any certainty of