Alcohol should be avoided, for it is a fat-sparer. The malt liquors are particularly unsuitable, for they contain a distinct amount of carbo-hydrate, some of them, e.g. Allsop's lager, cider and champagne perry, in the very considerable amounts of 5 to 11 per cent.
It is obvious that no diet can be at once devised which will suit every patient. We must take into consideration several facts. The weight of the individual varies and his metabolism varies under different conditions of life and environment. The metabolism of different people is variable. The tendency to obesity is not entirely dependent on the food supply. It is quite possible to reduce the supply of carbon-containing foods to a considerable extent and yet to find an actual increase in the obesity, because of improved digestion, absorption and assimilation. Such a result shows that deposition of fat can only take place at a certain rate, and cannot be regulated so as to vary directly with the food supply. Some of these cases of obesity in people on a limited diet have been regarded as morbid, the result of defective metabolism and imperfect oxidation, but they should rather be looked upon as resembling animals who thrive on little food. In the farmyard it is constantly found that some breeds of pigs fatten much more quickly and on much less food than other varieties. Further, we have to consider the effects of age, sex, temperament, occupation, climate and environment.
Hence, each case must be treated on its merits. Primarily it is essential to weigh the patient; to make a thorough physical examination, paying special attention to the circulatory and excretory organs, general health, vigour and absence of disease; to inquire into the family and the past history; and to ascertain carefully the habits as to food, sleep, work and exercise. Examine the urine, for a deficient excretion of urea and uric acid contra-indicates a liberal protein diet. The hereditary cases are the ones which benefit least from dietetic treatment. The self-indulgent individuals of the richer classes are the ones least likely to stick sufficiently long and rigidly to the dietetic restrictions necessary for permanent cure.
There are two methods of limiting the diet. In the first, the ordinary daily diet for a week must be weighed and then the quantities of the various constituents, according to which are excessive, must be reduced and the patient weighed weekly. In the second method, the number of calories of heat required for the patient, according to the age, weight and occupation, must be calculated. A diet containing food-stuffs to supply this amount is given for a week, and the amount is then reduced weekly in accordance with the effect on nutrition. It will be necessary to consider the calorific requirements of the normal diet.
The Mildest Cases Of Obesity , namely those of middle-aged men or women who are getting fatter than they care about, can be treated on very simple lines. It may be quite sufficient for the patient to omit sugar from the diet, replacing it by saccharin or saxin for sweetening purposes. The next step is reduction in the amount of bread, potatoes and other starchy foods. Alcoholic drinks should be limited or reduced in amount, and the total amount of fluids should be kept within reasonable limits. The omission of fluids at meal times may be an advantage. Next, the amount of fat taken should be reduced and cream entirely omitted. Finally, white bread can be replaced by the less nutritious wholemeal bread or partly by gluten bread or other anti-diabetic products.
Treatment on these lines is suitable for mild cases in people who can live an open air life, taking plenty of exercise, and not needing supervision; for those who can or must continue their usual avocations; in the presence of any morbid state which renders rapid reduction inadvisable; and as a preparation for more serious methods.
The Majority Of Patients Who Apply For Treatment are not satisfied with such simple advice. Though they may realize its value they will not control their appetites sufficiently to carry it out. Some of these can be more strongly influenced by rigid directions as to diet, the nature and amount of each meal, the weighing of the food and the record thereof, the weekly visit to the doctor, and the weekly weighing. Considerable reduction in the amount of fluid should be insisted on at first so that the loss of weight may be considerable and the patient favourably influenced, though the actual reduction in fat is slight. Still more likely are they to carry out directions if they pay in advance an unnecessarily high and inclusive fee for a course of treatment lasting for six weeks to three months or more. Unfortunately, even under these conditions, the favourable results are often merely temporary, for the obese seem much less able than the ordinary individual to resist the pleasures of the table. Most of the special diets are more or less starvation ones.
The calorie value of protein is 41, fat 9.3, and carbo-hydrate 41 (Rubner) per gramme. More recently Atwater has calculated these values at protein 44, fat 9.1, carbo-hydrate 4.1. Rubner's figures are the ones generally adopted. On a basis of these figures 100 grammes of fat are equivalent to 227 grammes of protein or carbo-hydrate.
A man weighing 70 kilos (11 stone) requires 40 calories of heat per kilo, or a total of 2,800 calories. This would be supplied by such diets as :
Rubner has estimated the number of calories required by a man of 70 kilos weight as 329 per kilo when resting, and 34.9, 41.0, 48.0, or 68.4 per kilo, according to the increase in the amount of the daily labour; the total number of calories rising from 2,303 to 4,790.
These figures afford a useful basis of computation for the suitable diet of any particular case. Anything beyond this may be stored up as fat, even an extra daily food supply of 200 calories taken in the form of about 1/2 pint of milk, 1 oz. of butter, 2 of cheese, 3 of bread, 3 or 4 of meat, or § of a pint of beer.
A study of experimental dietaries shows that the food taken daily should supply from 2,500 to 3,000 calories of heat; that in many circumstances a smaller amount is sufficient; that with increased work an increased amount is made use of. The total diet depends on the physique, the work and the result. In applying these facts to a case of obesity the calorie value of the food should be reduced at first by one-fifth, by the omission of sugar and alcohol from the diet and an increase in the exercise taken. By reducing the amount of bread and potato the calorie value can be reduced a further one-fifth. If it is desired to reduce the calorie value three-fifths, to 1,000 to 1,500 per diem, the patient at first must be kept in bed. Chittenden found 1,600 calories sufficient for a man of 57.5 kilos weight, that is, less than 30 calories per kilo of body-weight. As shown above, the number of calories needed per kilo, of body-weight varies with the output of energy of the individual, the external temperature, and other factors.
Certain special diets have been advocated for the treatment of obesity. Their description, advantages and drawbacks must be considered carefully before adopting any one of them.