THE NATURE OF OBESITY
Obesity a Disorder
As a basis for our discussion we postulate that obesity in all its many forms is due to an abnormal functioning of some part of the body and that every ounce of abnormally accumulated fat is always the result of the same disorder of certain regulatory mechanisms. Persons suffering from this particular disorder will get fat regardless of whether they eat excessively, normally or less than normal. A person who is free of the disorder will never get fat, even if he frequently overeats.
Those in whom the disorder is severe will accumulate fat very rapidly, those in whom it is moderate will gradually increase in weight and those in whom it is mild may be able to keep their excess weight stationary for long periods. In all these cases a loss of weight brought about by dieting, treatments with thyroid, appetite-reducing drugs, laxatives, violent exercise, massage, baths, etc., is only temporary and will be rapidly regained as soon as the reducing regimen is relaxed. The reason is simply that none of these measures corrects the basic disorder.
While there are great variations in the severity of obesity, we shall consider all the different forms in both sexes and at all ages as always being due to the same disorder. Variations in form would then be partly a matter of degree, partly an inherited bodily constitution and partly the result of a secondary involvement of endocrine glands such as the pituitary, the thyroid, the adrenals or the sex glands. On the other hand, we postulate that no deficiency of any of these glands can ever directly produce the common disorder known as obesity.
If this reasoning is correct, it follows that a treatment aimed at curing the disorder must be equally effective in both sexes, at all ages and in all forms of obesity. Unless this is so, we are entitled to harbor grave doubts as to whether a given treatment corrects the underlying disorder. Moreover, any claim that the disorder has been corrected must be substantiated by the ability of the patient to eat normally of any food he pleases without regaining abnormal fat after treatment. Only if these conditions are fulfilled can we legitimately speak of curing obesity rather than of reducing weight.
Our problem thus presents itself as an enquiry into the localization and the nature of the disorder which leads to obesity. The history of this enquiry is a long series of high hopes and bitter disappointments.
The History of Obesity
There was a time, not so long ago, when obesity was considered a sign of health and prosperity in man and of beauty, amorousness and fecundity in women. This attitude probably dates back to Neolithic times, about 8000 years ago; when for the first time in the history of culture, man began to own property, domestic animals, arable land, houses, pottery and metal tools. Before that, with the possible exception of some races such as the Hottentots, obesity was almost non-existent, as it still is in all wild animals and most primitive races.
Today obesity is extremely common among all civilized races, because a disposition to the disorder can be inherited. Wherever abnormal fat was regarded as an asset, sexual selection tended to propagate the trait. It is only in very recent times that manifest obesity has lost some of its allure, though the cult of the outsize bust – always a sign of latent obesity – shows that the trend still lingers on.
The Significance of Regular Meals
In the early Neolithic times another change took place which may well account for the fact that today nearly all inherited dispositions sooner or later develop into manifest obesity. This change was the institution of regular meals. In pre-Neolithic times, man ate only when he was hungry and on1y as much as he required too still the pangs of hunger. Moreover, much of his food was raw and all of it was unrefined. He roasted his meat, but he did not boil it, as he had no pots, and what little he may have grubbed from the Earth and picked from the trees, he ate as he went along.
The whole structure of man’s omnivorous digestive tract is, like that of an ape, rat or pig, adjusted to the continual nibbling of tidbits. It is not suited to occasional gorging as is, for instance, the intestine of the carnivorous cat family. Thus the institution of regular meals, particularly of food rendered rapidly assimilable, placed a great burden on modern man’s ability to cope with large quantities of food suddenly pouring into his system from the intestinal tract.
The institution of regular meals meant that man had to eat more than his body required at the moment of eating so as to tide him over until the next meal. Food rendered easily digestible suddenly flooded his body with nourishment of which he was in no need at the moment. Somehow, somewhere this surplus had to be stored.
Three Kinds of Fat
In the human body we can distinguish three kinds of fat. The first is the structural fat which fills the gaps between various organs, a sort of packing material. Structural fat also performs such important functions as bedding the kidneys in soft elastic tissue, protecting the coronary arteries and keeping the skin smooth and taut. It also provides the springy cushion of hard fat under the bones of the feet, without which we would be unable to walk.
The second type of fat is a normal reserve of fuel upon which the body can freely draw when the nutritional income from the intestinal tract is insufficient to meet the demand. Such normal reserves are localized all over the body. Fat is a substance which packs the highest caloric value into the smallest space so that normal reserves of fuel for muscular activity and the maintenance of body temperature can be most economically stored in this form. Both these types of fat, structural and reserve, are normal, and even if the body stocks them to capacity this can never be called obesity.
But there is a third type of fat which is entirely abnormal. It is the accumulation of such fat, and of such fat only, from which the overweight patient suffers. This abnormal fat is also a potential reserve of fuel, but unlike the normal reserves it is not available to the body in a nutritional emergency. It is, so to speak, locked away in a fixed deposit and is not kept in a current account, as are the normal reserves.
When an obese patient tries to reduce by starving himself, he will first lose his normal fat reserves. When these are exhausted he begins to burn up structural fat, and only as a last resort will the body yield its abnormal reserves, though by that time the patient usually feels so weak and hungry that the diet is abandoned. It is just for this reason that obese patients complain that when they diet they lose the wrong fat. They feel famished and tired and their face becomes drawn and haggard, but their belly, hips, thighs and upper arms show little improvement. The fat they have come to detest stays on and the fat they need to cover their bones gets less and less. Their skin wrinkles and they look old and miserable. And that is one of the most frustrating and depressing experiences a human being can have.
Injustice to the Obese
When then obese patients are accused of cheating, gluttony, lack of will power, greed and sexual complexes, the strong become indignant and decide that modern medicine is a fraud and its representatives fools, while the weak just give up the struggle in despair. In either case the result is the same: a further gain in weight, resignation to an abominable fate and the resolution at least to live tolerably the short span allotted to them – a fig for doctors and insurance companies.
Obese patients only feel physically well as long as they are stationary or gaining weight. They may feel guilty, owing to the lethargy and indolence always associated with obesity. They may feel ashamed of what they have been led to believe is a lack of control. They may feel horrified by the appearance of their nude body and the tightness of their clothes. But they have a primitive feeling of animal content which turns to misery and suffering as soon as they make a resolute attempt to reduce. For this there are sound reasons.
In the first place, more caloric energy is required to keep a large body at a certain temperature than to heat a small body. Secondly the muscular effort of moving a heavy body is greater than in the case of a light body. The muscular effort consumes Calories which must be provided by food. Thus, all other factors being equal, a fat person requires more food than a lean one. One might therefore reason that if a fat person eats only the additional food his body requires he should be able to keep his weight stationary. Yet every physician who has studied obese patients under rigorously controlled conditions knows that this is not true. Many obese patients actually gain weight on a diet which is calorically deficient for their basic needs. There must thus be some other mechanism at work.
At one time it was thought that this mechanism might be concerned with the sex glands. Such a connection was suggested by the fact that many juvenile obese patients show an under-development of the sex organs. The middle-age spread in men and the tendency of many women to put on weight in the menopause seemed to indicate a causal connection between diminishing sex function and overweight. Yet, when highly active sex hormones became available, it was found that their administration had no effect whatsoever on obesity. The sex glands could therefore not be the seat of the disorder.
The Thyroid Gland
When it was discovered that the thyroid gland controls the rate at which body-fuel is consumed, it was thought that by administering thyroid gland to obese patients their abnormal fat deposits could be burned up more rapidly. This too proved to be entirely disappointing, because as we now know, these abnormal deposits take no part in the body’s energy-turnover – they are inaccessibly locked away. Thyroid medication merely forces the body to consume its normal fat reserves, which are already depleted in obese patients, and then to break down structurally essential fat without touching the abnormal deposits. In this way a patient may be brought to the brink of starvation in spite of having a hundred pounds of fat to spare. Thus any weight loss brought about by thyroid medication is always at the expense of fat of which the body is in dire need.
While the majority of obese patients have a perfectly normal thyroid gland and some even have an overactive thyroid, one also occasionally sees a case with a real thyroid deficiency. In such cases, treatment with thyroid brings about a small loss of weight, but this is not due to the loss of any abnormal fat. It is entirely the result of the elimination of a mucoid substance, called myxedema, which the body accumulates when there is a marked primary thyroid deficiency. Moreover, patients suffering only from a severe lack of thyroid hormone never become obese in the true sense. Possibly also the observation that normal persons – though not the obese – lose weight rapidly when their thyroid becomes overactive may have contributed to the false notion that thyroid deficiency and obesity are connected. Much misunderstanding about the supposed role of the thyroid gland in obesity is still met with, and it is now really high time that thyroid preparations be once and for all struck off the list of remedies for obesity. This is particularly so because giving thyroid gland to an obese patient whose thyroid is either normal or overactive, besides being useless, is decidedly dangerous.
The Pituitary Gland
The next gland to be falsely incriminated was the anterior lobe of the pituitary or hypophysis. This most important gland lies well protected in a bony capsule at the base of the skull. It has a vast number of functions in the body, among which is the regulation of all the other important endocrine glands. The fact that various signs of anterior pituitary deficiency are often associated with obesity raised the hope that the seat of the disorder might be in this gland. But although a large number of pituitary hormones have been isolated and many extracts of the gland prepared, not a single one or any combination of such factors proved to be of any value in the treatment of obesity. Quite recently, however, a fat-mobilizing factor has been found in pituitary glands, but it is still too early to say whether this factor is destined to play a role in the treatment of obesity.
Recently, a long series of brilliant discoveries concerning the working of the adrenal or suprarenal glands, small bodies which sit atop the kidneys, have created tremendous interest. This interest also turned to the problem of obesity when it was discovered that a condition which in some respects resembles a severe case of obesity – the so-called Cushing’s Syndrome – was caused by a glandular new-growth of the adrenals or by their excessive stimulation with ACTH, which is the pituitary hormone governing the activity of the outer rind or cortex of the adrenals.
When we learned that an abnormal stimulation of the adrenal cortex could produce signs that resemble true obesity, this knowledge furnished no practical means of treating obesity by decreasing the activity of the adrenal cortex. There is no evidence to suggest that in obesity there is any excess of adrenocortical activity; in fact, all the evidence points to the contrary. There seems to be rather a lack of adrenocortical function and a decrease in the secretion of ACTH from the anterior pituitary lobe. *
So here again our search for the mechanism which produces obesity led us into a blind alley. Recently, many students of obesity have reverted to the nihilistic attitude that obesity is caused simply by overeating and that it can only be cured by under eating.
The Diencephalon or Hypothalamus
For those of us who refused to be discouraged there remained one slight hope. Buried deep down in the massive human brain there is a part which we have in common with all vertebrate animals, the so-called diencephalon. It is a very primitive part of the brain and has in man been almost smothered by the huge masses of nervous tissue with which we think, reason and voluntarily move our body. The diencephalon is the part from which the central nervous system controls all the automatic animal functions of the body, such as breathing, the heart beat, digestion, sleep, sex, the urinary system, the autonomous or vegetative nervous system and via the pituitary the whole interplay of the endocrine glands.
* There is some clinical evidence to suggest that those symptoms of Cushing’s Syndrome which resemble true obesity are caused by the same mechanism which causes common obesity, while the other symptoms of the syndrome are directly due to adrenocortical dysfunction.
It was therefore not unreasonable to suppose that the complex operation of storing and issuing fuel to the body might also be controlled by the diencephalon. It has long been known that the content of sugar – another form of fuel – in the blood depends on a certain nervous center in the diencephalon. When this center is destroyed in laboratory animals, they develop a condition rather similar to human stable diabetes. It has also long been known that the destruction of another diencephalic center produces a voracious appetite and a rapid gain in weight in animals which never get fat spontaneously.
Assuming that in man such a center controlling the movement of fat does exist, its function would have to be much like that of a bank. When the body assimilates from the intestinal tract more fuel than it needs at the moment, this surplus is deposited in what may be compared with a current account. Out of this account it can always be withdrawn as required. All normal fat reserves are in such a current account, and it is probable that a diencephalic center manages the deposits and withdrawals.
When now, for reasons which will be discussed later, the deposits grow rapidly while small withdrawals become more frequent, a point may be reached which goes beyond the diencephalon’s banking capacity. Just as a banker might suggest to a wealthy client that instead of accumulating a large and unmanageable current account he should invest his surplus capital, the body appears to establish a fixed deposit into which all surplus funds go but from which they can no longer be withdrawn by the procedure used in a current account. In this way the diencephalic “fat-bank” frees itself from all work which goes beyond its normal banking capacity. The onset of obesity dates from the moment the diencephalon adopts this labor-saving ruse. Once a fixed deposit has been established the normal fat reserves are held at a minimum, while every available surplus is locked away in the fixed deposit and is therefore taken out of normal circulation.