Dieting and the Mind: Hindbrain

If you’ve been dieting for weight-loss for some time and have found that the diet isn’t “working” – by whatever measure you care to apply – then the reason for this has to be to do with diet, or it has to do with how you are mentally and physiologically responding.

Let’s start by fuelling the fires of controversy a little more! As you discover more and more about the many and marvellous alternative diets – and there is really an embarrassment of riches here – you’ll soon come across the, sometimes quite vitriolic, arguments that rage between followers of ketogenc diets (most characteristically, Dr Atkins’ Diet), and low-fat (with or without high fibre) diets. There are too many examples of these to isolate one. The basic principle which underpins our work with the Median Diet is that they are both right.

q There is no such thing as a weight-loss diet which provides you with a sum total of fewer calories to burn than you actually do burn.
q Secondly, all diets are ketogenic. That is, at some point in the metabolic cycle they all work on same the biochemical principle of burning fat.

Why do we emphasis that? Because we want to prove to you that any weight-loss diet will “work” in purely biochemical/physiological terms so long as it meets the critical condition of providing you with fewer calories than you need to survive.

If a diet of choice isn’t working, then, the reasons probably have to do with your personal mental and physiological response. It is beyond the scope of this article to address problems with dieting that arise as a result of individual differences in metabolism. If you do find that, despite your best efforts, you still fail to lose weight on the assumption that you ingest fewer calories than you burn, then your metabolic rate will be different from “normal” – in the sense of usual. It might be indicative of an underlying medical condition, so – at that point, and in this case – take professional advice from your medical practitioner. It may be genetic in which case difficulty in achieving weight-loss while dieting is truly individual. That is not to say, however, that mental exercises could not help in some small way to overcome the obstacle. Recent research shows that even genes are responsive to thoughts . Responses in the mind, however, are a different matter. These do vary enormously and are concerned with:
how we neurologically and physiologically register the need to eat (the why);
and how we actually go about eating (not only the chomping part, but context as well! The how.) By taking a close look at the why and how we can begin to get a handle on eating as a behaviour and thus modify it. Bear in mind that if the maths of the chosen diet is right, only by modifying the associated behaviour can you transform failure into success!

There are three basic ways our minds/brains deal with nutrition and eating because, in effect, we have three brains! Studies of brain development in humans over real time as foetal growth and in neuro-physiological development up to the age of 21, and studies of how brain structures have evolved over historical time shows progression through three distinctive structures. Most primitively is the instinctual and autonomic response. Then there is the emotional level and, lastly, the rational or intellectual.

Inside your head there are three brains. Or, more precisely, three distinctive structures that, together, make the human brain as we know it. These are shown in the diagram below: (1.) the hindbrain, (2) the limbic system or mid-brain and, (3) the neo-cortex. This, of course, is a vastly simplified scheme but shows where, in broad outline, the various types of thinking lie:

The Hindbrain, (1), evolutionarily speaking, the most basic and rudimentary brain is sometimes called the reptile, or R-brain. This is the part of the brain that deals with the unconscious actions that are normally beyond our immediate control, like breathing, perspiring, heartbeat and so on. It also deals with instinctive, life-threatening situations.

The limbic system, or mid-brain (2.), like the hindbrain includes a number of smaller bodies or areas, such as the amygdala, each with specialized functions. The role of the limbic system (so called because it looks like arms encircling the hindbrain) is to produce and control emotions. It is sometimes called the old mammalian brain because the brains of primitive mammals look very much like the limbic system.

Last of all comes the cortex (3.) (meaning bark - as in bark of tree) which is built up in layers and lobes. This is the most sophisticated part of the brain yet, surprisingly, in terms of our functioning as living organisms it is the least important.

Unfortunately, as the way that each of the three sections inputs, processes and responds to stimuli teasing out each strand can be a little complicated, but as the inputs and outputs are so different, they are definable. A second problem is that there is a clear hierarchy of inputs and responses, a bit like the scissors, stone paper game. Most of the time this is so for helpful reasons – like survival. Sometimes, however, lower brain activity can get in the way.

Starting with (1.), the hindbrain, eating is usually a conscious activity: we do not eat in our sleep even though hunger signals may perfectly well be sent from the stomach and gut to the hindbrain. On an unconscious level we may dream about food, and when in a trance-like or daydreaming state fantasize about food. There are occasions when eating can be a semi-conscious activity such as when the consciousness or attention is almost fully occupied elsewhere. Grazing on popcorn while watching a film or eating a TV-dinner (while watching TV) are cases in point. These are examples where the actual actions involved in eating are semi-automatic. This kind of semi-conscious activity merits separate consideration.

For now, however, consider that food or nourishment is essential for survival: if we don't get the energy we need from food, we die. This is truly a “need” (as opposed to “desire”), and that is why, as the first part of the nutritive process, it is controlled by the hindbrain. On one level, we actually have very little control over the hindbrain's responses to and need for nourishment triggered by huger pangs, and very quickly allow ourselves (like Pavlov's dogs) to become conditioned to certain eating habits regardless of whether we feel those hunger pangs or not. There is sensory input from the mouth, nose, stomach and gut which also needs to be processed and an appropriate neural/behavioural response given.

The hindbrain does not possess the vocabulary or even the concept of a weight-reducing diet. It is only concerned with three things: should I kill it? Should I eat it? Should I have sex with it? So that a major focus of working on mind training to enhance dieting is involved with finding a way round, or of sabotaging in the reptilian brain! Scissors, stone, paper comes into the hindbrain’s workings in the sense that it was designed to respond immediately. Imagine you suddenly hear the hissing or rattling of a snake: the body does not require either the time or leisure rationally to process that information in a rational way. You might well be on the way to being dead by the time your rational brain had come up with appropriate behaviour as neural signals travel at only 30m/s and would have some way to go even were you able to make an instantaneous response when the messages got to the cortex. Instead, the hindbrain immediately triggers the appropriate responses via the amygdala – a kind of instantaneous mental switch - which guarantee safety. Now, eating as a behaviour, is governed by the hindbrain and isn’t really concerned with inputs as threats in quite the same way. Hunger pangs are the obvious sensory input stimulus, and a feeling of fullness or satiety is the second sensory input after eating. (Apart from the purely sensual or gustatory pleasures which are somewhat different: so we’ll deal with them separately.) Messages from the stomach and gut reach the hindbrain much more slowly: indeed, some researchers reckon it can take twenty minutes for the “need food” signals to reach the conscious mind. (Hunger pangs start as unconscious neural signals: we haven’t eyes or ears in our tummies!) The same is true of satiety signals.

Curiously (if not, alas, surprisingly) these satiety signals have always been the focus of much attention in the diet-food industry. Typically, substances such as guar or xanthan gum are added to products such as yoghurt to help artificially induce a feeling of fullness or satiety. I like my yoghurt to taste of yoghurt and am not particularly keen on eating gum when I want to eat yoghurt. (My grandmother certainly wouldn’t have known what guar gum was! So campaigners for “real” food would be happy there!) However, on the plus side, this gives us a clue as to how we can manipulate the unconscious (in the sense of primitive) inputs of the hind-brain and that is by regulating or diverting the hunger signals and suppressing or limiting the need to eat. Remember, the need to eat is different from the desireto eat: the desire to eat can be called appetite. We take the word “appetite”, here, to mean something rather different to hunger pang. The appetite – or conscious desire to eat – is the product of mood and emotions, experience, expectations, habits, learned behaviour. And just as a lot of behaviour can be learned, so it can be unlearned. But that is a separate issue.

Suppressing hunger pangs
A curious feature of the unconscious mind and of the autonomic system (the primitive unconscious mind) is that it cannot distinguish between different qualities that trigger particular neural signals. When your tummy is empty, for instance, the R-brain registers only that you absolutely require food as a biological need. The same applies after eating: satiety signals register only that the stomach is full: no information is either required or given. Now, apart from dealing with feelings of hunger in a rational and reasoned way (which can be done) all we need be concerned with, for the moment, is removing the physiological triggers.

If we can find a way of stopping or of limiting the signals then neural messages saying “eat now” will just not arrive: consequentially, you shouldn’t feel the need to eat.

Before your meal, try:
o drinking a glass of water, or
o eating an apple, or even half an apple;
o a small quantity of unsaturated fat (ideally, about 65g) in the form of nuts, seeds or fish triggers the “full-up” response. Pine nuts or pine kernels which contain naturally occurring pinolenic acid (another appetite suppressant) are especially good.

On the same principle that a golfer tries a practice swing before teeing-off (her unconscious mind cannot distinguish between the real teeing-off swing and the practice swing), or a pianist practising a difficult passage on the table (look up André Previn’s fabled encounter with Georg Szell!) water has the effect of filling the tummy. Not as effectively as an apple, maybe – an apple has much more fibre – but the sensation of fullness is the same. This is precisely the reasoning behind Drs Roizen and Oz’s recommendation of 65g unsaturated fat.

At the beginning of the meal:
o eat protein, preferably, to enhance the sense of fullness;
o eat bulky leafy vegetables to fill up, preferably as a separate course.

Proteins and complex carbohydrates are best at sending “full-up” satiety signals to the hindbrain; they also have different metabolic rates of conversion (as opposed to values – both provide around 4 kcal/g) but protein can have the effect of speeding-up the metabolism. Again, there are differences between animal-based proteins and vegetable based: animal-based proteins are burned at a higher, more rapid metabolic rate. Vegetables high in fibre and water are, obviously, far more effective at sending “full-up” signals to the hindbrain than fatty foods (with the possible exception of olive oil).

On this basis there is a great deal of common sense behind the traditional gourmet cuisine tradition of eating meat (or fish) and vegetables as separate courses. A dish of braised celery with a touch of butter and black pepper, for instance, after a plate of meat would not be out of place in this tradition of cooking. In Britain we are far more likely to tip everything onto the plate in one super-size course. It is more than likely that this concept of separateness, apart from encouraging positive dining habits (like savouring and individually enjoying largely unadulterated foodstuffs of the highest quality) is a contributory factor in the Mediterranean diet and diets from other parts of France, for instance, which, at first sight, appear tremendously unhealthy yet are unlinked to incidence of heart disease and poor health.

Whilst eating:
o Take your time eating: stay focused on task, and chew thoroughly.
o Try soup as a filler. (Pureed vegetables with a stock are especially amenable to this sort of treatment.)
o Take a salad as a separate course (on the same principle as a separate vegetable dish): even shredded cabbage dressed with a little cider vinegar or carrot dressed with a few drops of sesame oil will do.

The action of chewing releases hormones which trigger satiety signals: the process is not instantaneous: eat slowly and make an effort to chew and enjoy your food by using all your senses. Each has an input into triggering the satiety signal. Sight, smell and texture (sensed by mouth, tongue) certainly, if not hearing! Once again, gourmet cuisine traditions have something to teach us here: hors d’oeuvres and salads, judiciously chosen, actually trigger the signals that stop the hunger pangs and might have the effect of limiting the total calorific intake.

At the end of the meal (or towards the end):
o avoid puddings: if you must have a little something else try a smidgin of cheese on celery or with a slice of apple.

Sweetness sensed by the tongue can easily over-ride satiety signals, so sweet things are best avoided: especially in the closing stages of a meal – quite contrary to what we would normally do. Yet again, fine-dining offers some practical habits we seem to have forgotten: by finishing with protein we “round-off” the process and are far more likely to feel full up.

The sense of fullness or satiety is a characteristic function of the hindbrain. This sensation has noting at all to do with rationality or logic. It, like hunger pangs, is quite primitive and can be dealt with in those terms. Emotion and aesthetic appreciation have nothing, really, to do with it (notwithstanding that by taking your time to eat and enjoy the experience you do engage emotion if not intellect). The hindbrain – so far as nutrition and eating is concerned – is easily fooled!

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