‘As I watch this kind of impulsive behaviour, I suspect a battle may be taking place in their heads, the struggle between “I want” and “I shouldn’t,” between “I’m in charge” and “I can’t control this.” In this struggle lies one of the most consequential battles we face to protect our health.’
David Kessler, The End of Overeating1
IN THE UNIVERSITY of Sussex’s Ingestive Behaviour laboratory, a young woman is inflating a total of thirty virtual balloons on a computer screen. With each click of the mouse button, a bright red balloon gets larger and she earns more money, and increases her probability of winning a $50 voucher. But each click is fraught with risk; if overinflated, the balloon will burst and all her earnings will be lost. Because each of the balloons has a different bursting point, she has no way of knowing the extent to which any one of them can be safely blown up. As we watch, she hesitates for a moment before risking a further click. The balloon swells but remains intact. Her look of relief rapidly changes to one of uncertainty. Should she click again in the hope of earning a higher reward, or stop and safeguard what she has earned?
Over the course of twenty days, sixty-four participants take part in this nail-biting game of dilemma, known as the Balloon Analogue Risk Task or BART.2 It is a challenge which allows psychologists to assess a participant’s propensity for risk-taking and impulsivity, based on counting how many balloons they burst. The BART, a widely employed and well-validated test, shows clear differences in impulsivity between different categories of people.3 It can, for example, discriminate between smokers and nonsmokers, as smokers burst more balloons.4
Since the purpose of this research was to investigate the link between impulsivity and overeating, inflating balloons formed only part of the study. To their delight the participants also had to eat a chocolate ice-cream sundae and binge on a selection of delicious, high-calorie snacks. Why they were required to treat themselves in this way we will explain shortly.
Although not widely known outside nutritional and dietary research, the concepts of dietary boundaries and dietary restraint have, for more than thirty years, exerted a powerful influence on psychological thinking about individual differences in eating behaviour.5 A dietary boundary is a self-imposed limitation or rule for eating; it can be in the form of caloric restriction (‘I must not consume more than 1,200 kcal’), or in the form of reduction of a macronutrient such as fat or carbohydrate.
When following a weight-control programme, dietary boundaries can be extensive and specific. For example, during the two-week-long induction stage of the Atkins Diet (the period when the greatest weight loss usually occurs), alcohol is banned, caffeine intake reduced to a minimum and carbohydrate consumption limited to fewer than 20 ‘net grams’ per day. ‘Net grams’ means the total carbohydrate content of the foods, less the fibre – that number represents the grams of carbohydrate that have a significant impact on blood sugar levels. Foods with a good fibre-to-carbohydrate ratio are sometimes described as ‘good carbs’.6 Monitoring ‘net carbs’ and staying within defined limits of consumption is one kind of dietary boundary; others could refer to calories consumed, fat consumed, or any other imposed restriction to promote weight loss.
However, while theoretically a good idea, in practice these boundaries are also too easy to violate. Imagine that while following a diet, you are asked to dinner by a friend who happens to be an excellent cook. You are served a generous portion of homemade steak-and-kidney pudding, clocking in at over 400 calories. It is delicious and you clear your plate. Your host offers a second helping but your dietary boundaries include never having a second helping. However, to refuse might offend them. So, after a moment’s hesitation, you take up the offer. Once again you finish every morsel. Dessert, a rich gateau served with ice cream, arrives. Normally you would politely decline, since another of your boundaries involves no high-calorie treats! On this occasion, aware of having already crossed your dietary boundaries you think, ‘What the hell!’, and accept two more helpings.7 If you have ever struggled to control your weight, then this scenario will sound all too familiar.
The Restraint Scale is a tool used by psychological researchers to quantify self-control in the realm of eating behaviour. Individuals who set themselves a large number of dietary boundaries score ‘high’ on this scale. While being able to control what you eat should obviously be a good thing, researchers have speculated that such people may try to consume fewer calories than their body actually needs for healthy metabolism, leading to feelings of deprivation. Therefore, the self-imposed boundaries can, in some cases, lead to an increased risk of binge eating and development of eating disorders such as bulimia.8 During the 1980s, in order to gain a greater understanding of dietary restraint, Peter Herman and Janet Polivy from the University of Toronto gave identical bowls of ice cream to both restrained and unrestrained eaters. They found, to no one’s great surprise, that the subjects who had been rated as more restrained subjects ate significantly less than the latter. Yet when they instructed both groups to drink a calorie-rich milkshake immediately before eating the ice cream, the outcome was unexpectedly reversed. In that scenario, restrained eaters consumed twice as much as unrestrained ones. This brings us back to the surprising findings of our balloon-bursting study, and the importance that a person’s psychological profile has on eating behaviour.
Before being selected for the study, all the volunteers – none of whom were overweight – completed a questionnaire designed to provide information about their attitudes towards food in general and dieting in particular. They were asked, for example, to tick True or False to statements such as:
Their responses placed them in one of two groups. Group A consisted of women who had tried, often on several occasions, to go on a formal diet (Unsuccessful Dieters), or whose weight tended to yo-yo (Weight Fluctuators). These two subgroups together were comparable to ‘What-the-Hell’ type dieters who, after encountering a challenge with dieting, have a tendency to throw in the towel. In Group B were those who had either succeeded in dieting (Successful Dieters) or were able to maintain a healthy weight while imposing few, if any, restrictions on what they ate (Unrestrained Eaters). We referred to them collectively as ‘Successful Dieters’.
We compared the reactions of the What-the-Hell types, to the Successful Dieters to investigate whether their eating habits could be linked with other kinds of traits, such as impulsivity.
The participants in the study had been asked not to eat or drink anything after 11 p.m. the previous night, which meant they were all distinctly hungry on arriving at the lab. There they were given a light breakfast, comprising some orange juice and a bowl of Crunchy Nut Cornflakes with semi-skimmed milk amounting, in total, to exactly 400 calories.
After breakfast, each was weighed. They were then asked to refrain from eating and to drink only water before returning, three hours later, to undertake a variety of tests and to consume a chocolate and ice-cream sundae. Apart from ensuring the volunteers felt comfortably full, this 370-calorie snack had a more devious purpose. As in Peter Herman and Janet Polivy’s study, we were compelling the subjects to violate their dietary boundaries, by providing them with high-calorie treat and insisting they ate the lot. After they had finished their chocolate ice-cream sundae, the volunteers were offered a selection of high energy-dense snacks, including chocolate buttons, biscuits and dry-roasted peanuts. They were invited to consume as many or as few as they wished.
As predicted, the What-the-Hell Dieters ate upwards of 300 kcal more snacks than Successful Dieters and Unrestrained Eaters. Following this snacking binge, the volunteers then undertook the virtual balloons test once more.
It had been expected that after eating so much high-fat, high-sugar food – some participants had consumed upwards of 800 calories of pure sugar – both groups would become more impulsive. This was based on the assumption that What-the-Hell Dieters failed to stick to diets because they ate impulsively anyway, and that because they had already been compelled to violate their dietary boundaries, Successful Dieters would feel as though they could continue to do so.
This was not, however, what actually happened. While, as predicted, the What-the-Hell group behaved more impulsively prior to eating HED foods they became less impulsive after doing so! It was the Successful Dieters who became more impulsive after the high calorie snack, who took greater risks and so burst more balloons.
So eating energy-dense foods actually made people who usually have difficulty controlling their impulses better able to do so. Might this suggest that naturally impulsive people sometimes eat to excess because this makes it easier for them to exert self-control in other situations?
While the fact that people ‘comfort-eat’ when upset or stressed is well known (see Chapter 10 for a more detailed discussion), the notion that overeating might be used to reduce impulsivity had not previously been investigated. These results suggest something interesting and important: people who have great difficulty controlling their weight are not necessarily hungrier; rather their psychological profile and life circumstances might be the key contributing factors that lead to overeating, as they may be using food as a psychological crutch.
So, if you see yourself as a weight cycler, it’s very likely you may unconsciously use food to help you concentrate or to overcome stressful situations. You may have a tendency to snack at your desk during times of stress, or you may find you are less irritable when junk food is available.
The way to reduce the gnawing cravings is to simply not allow yourself to give in. That, of course, is much easier said than done. The key is to try to alter other elements of your lifestyle to give yourself a greater chance of resisting your impulsive urges. By getting more sleep and incorporating exercise into your daily routine, you can take significant steps in this direction.9
For example, in an investigation of over 2,000 New England homes, it was found that moderately active to very active people tended to consume more fibre, less total fat, higher dietary fibre, reduced cholesterol, and follow diet guidelines more carefully than less active people.10 Yet it’s not simply the fact that healthy people engage in healthy behaviours, rather that scientists are beginning to suggest that physical activity may reduce impulsivity via neurocognitive mechanisms, which would allow a person to avoid eating impulsively without having to register the act mentally. They would just do it.
Decision-making, regardless of what the task at hand may be (whether eating or otherwise) is evaluated rationally, or influenced by emotions, and a surge of data demonstrates that physical activity improves mood. Improved mood may yield fewer impulsively based decisions for eating. Moreover, exercise is positively correlated with neurogenerative, neuroadaptive, and neuroprotective process.11
For example, a study of adults who completed a six-month walking regime showed they not only became more aerobically fit, but showed improved decision-making. This cognitive improvement was defined by their performance on selective attention tasks, and ‘stop signal’ paradigms which measure an individual’s propensity for impulse control.12
If exercise helps reduce impulsivity, it seems a safe assumption that a lack of physical activity will lead to greater impulsivity. This is indeed the case. In a unique investigation at Berlin’s Centre for Space Medicine, scientists investigated twenty-four males who were put in a bed-rest model of ‘prolonged weightlessness’, with the bed slightly tilted at 6 degrees. Their scores on a psychological tool to assess impulsivity and risk-taking, known as the Iowa Gambling Task, showed greater impulsivity after the session of weightlessness than before. In a real-world context, this may explain the link between sedentary behaviour such as TV viewing and increased eating.
To summarise, physical activity can help build cognitive resources, such as inhibitory control, which can ultimately contribute to tighter control of eating motivation, and eventually a reduced need to eat for emotional reasons.
Impulsivity was once regarded as a fixed personality trait, something you were born with, like blue eyes or blonde hair, but we now know it depends as much on context as on inborn characteristics – individuals able to exercise great self-restraint in one situation may find it almost impossible to do so in another.
A large and fast-growing volume of research has also demonstrated the extent to which impulsivity significantly increases an individual’s risk both of becoming obese and developing a range of eating disorders, including both binge and binge/purge eating.13 Impulsivity is not only a precursor to overeating, but may also be linked to a person’s perception of, and sensitivity to, the rewarding properties of HED foods as discussed in the previous chapter.14 Foods with high levels of sugars and fats can trigger a craving to consume them again – as dopamine levels dissipate, the person is left wanting more.15 The fact we use the word ‘craving’ to describe an intense desire in the context of both food and illegal drugs is no mere accident of language; as we have seen, the impulse to overeat is produced in the same brain regions as those associated with drug addiction.
Why do some people find it so hard to exercise control over their impulses when it comes to eating healthily or following a diet? The main factor, according to some psychologists, actually lies in the process of self-control itself.
‘Self-control resembles a muscle in more ways than one,’ believes Roy Baumeister, Professor of Psychology at Florida State University in Tallahassee. ‘Not only does it show fatigue, in the sense that it seems to lose power right after being used, it also gets stronger through exercise.’16
In a 1998 study conducted by Roy Baumeister and his colleagues from Case Western Reserve University, sixty-seven psychology students (thirty-one men and thirty-six women) were recruited to participate in what they believed was a taste perception test. Arriving at the laboratory they were shown two types of food. One was a pile of freshly baked chocolate chip cookies, whose mouthwatering aroma filled the laboratory, the other was a bowl of red and white radishes. They were told that these had been chosen for the study because they were ‘highly distinctive foods, familiar to most people.’
The students were then assigned to one of four groups. The first was asked to taste the chocolate chip cookies, and a few radishes. The second to eat only the cookies, the third only the radishes. Those in the final group were offered no food at all and moved directly to the second part of the study, which involved problem solving. Having issued these instructions, the psychologist left the room but continued to observe the groups through a one-way mirror, recording the amount of food eaten and checking that the three groups ate only the foods assigned to them. After five minutes she returned to set all four groups the task of solving a problem, which was in fact unsolvable. It involved trying to trace a geometric figure without going back over any of the lines or lifting the pen from the paper. They were told: ‘You can take as much time and as many trials as you want . . . If you wish to stop before you finish [i.e. before you’ve solved the problem], ring the bell on the table.’17
This, although the students did not know it of course, was the crux of the experiment. The hypothesis that Baumeister and his team was testing was that those compelled to eat only radishes and watch while their more fortunate companions enjoyed the cookies would give up on the puzzle test faster. In short, they thought having to exercise self-control to ignore the tempting cookies would then leave them less able to struggle against their frustration with the impossible task. The psychologists noted that while none of those in the ‘radish only’ group grabbed a cookie when left alone in the room, several, in Baumeister’s words, looked ‘longingly at the chocolate display and in a few cases even picked up the cookies to sniff them’. Subsequently these ‘deprived’ students spontaneously admitted they had experienced great difficulty in resisting the temptation to eat the cookies.
The results bore out the researcher’s hypothesis. Those who had been allowed to eat cookies made 34 attempts to solve the problem over a period of nearly 19 minutes. Those who had not been offered any snacks at all made only slightly fewer attempts (32) over a somewhat longer period (21 minutes). However, the radish only group did, as predicted, abandon the challenge far earlier. They made only 19 attempts and gave up after just 8 minutes.
‘Resisting temptation seems to have produced a psychic cost,’ notes Roy Baumeister, ‘in the sense that afterward participants were more inclined to give up easily in the face of frustration. It was not that eating chocolate improved performance. Rather, wanting chocolate but eating radishes instead, especially under circumstances in which it would seemingly be easy and safe to snitch some chocolates, seems to have consumed some resource and therefore left people less able to persist at the puzzles.’18
Variations on this type of experiment have consistently supported the finding that exercising restraint in one situation reduces one’s ability to exercise it in another. In a more recent study, participants whose self-control had been depleted chose relatively trashy films over more intellectual or artistic movies. These preferences occurred even when selecting a film to watch in several days’ time.19 And in another study, participants whose self-control had been depleted favoured sweets over healthier granola bars as a snack. The amount of food consumed under these circumstances was also affected. Dieters ate more food when their self-control had been depleted than they would otherwise have done, while those not on a diet remained relatively unaffected.
‘The distinction is important,’ points out Roy Baumeister, ‘because it suggests that . . . depletion does not simply increase appetites or pleasure seeking. Rather, it undermines the defences and the virtuous intentions that would otherwise guide behaviour.’20
The previous study demonstrates a key point: if you employ a lot of self-control in one area of life then you will find it harder to do so in other areas. So someone who struggles with impulsive overeating will find it harder to resist those impulses if they have already depleted their capacity for self-control by using it in other contexts. When we begin to understand self-control in this way, as being almost like a finite resource, then we see that in some situations a person can no more prevent themselves from overeating than a car can keep running when the petrol tank is empty.
Self-control, however, does more than keep our impulses in check. It forms part of a much larger collection of executive functions concerned with self-monitoring, coping with stress, considering different options, weighing up alternatives, and making decisions. And all of these draw on the same limited ‘resource’ of our character as well. It may be the case that certain times are fraught with so much stress that it limits our abilities for self-control. Thus, learning to exercise self-control and expand it like a muscle is very likely to contribute to a better relationship with food, even in difficult times.
Self-control depletion can also come about merely by watching others exert willpower. In a recent study by Joshua M. Ackerman of Yale University and his colleagues, undergraduates were asked to read a story about a hungry waiter or waitress (matched to the sex of the participant) working in a high-quality restaurant, who was forbidden to eat while at work on pain of being fired. The story, written in the first person, described in great detail all the mouthwatering dishes being served and how difficult it was to resist the temptation of sneaking a morsel to assuage their appetite. Half the students were told to read the story while the other half were asked to try and ‘really imagine yourself in his or her shoes, and concentrate on trying to imagine what the person was thinking and how he or she was feeling.’21 They were then shown pictures of various mid- to high-priced products like watches or cars, and asked how much they would be prepared to pay for them. The results were surprising. Those who had been asked vividly to imagine the plight of the waiter, and truly immerse themselves in the waiter’s situation, were willing to spend more than $6,000 more than participants who had simply read the story.
‘The findings from the current research suggest that the ability to control one’s own thoughts, feelings, and behaviours is influenced by the self-control of other people,’ wrote Joshua M. Ackerman, ‘and by how closely one’s mind mirrors the minds of others, in ways one might not generally expect.’22 This, and similar studies, offers a caution to anyone who believes that joining a group of fellow dieters will make it easier to resist temptation – striving to exercise self-control while watching others do the same may, in fact, make it harder.
‘Self-control is one of the defining features of the human animal,’ according to Michael Inzlicht of the University of Toronto and Brandon Schmeichel of Texas A&M University. ‘Its failure is one of the central problems of human society, being implicated in phenomena ranging from criminality to obesity, from personal debt to drug abuse.’23
So if it is so important to our health and wellbeing, why does self-control so often fail? Often, we have to look at peripheral factors, such as sleep loss, that may contribute to our inability to withhold from immediate desires.
Over the past ten years, the number of hours people spend asleep has significantly declined across many parts of the world, just as obesity levels have dramatically increased.24
Could these two events be related?
Epidemiological studies propose a U-shaped relationship between the two, meaning that both having too little or too much sleep leads to an increase in body weight. Sebastian Schmid and his colleagues from the University of Lübeck and the Interdisciplinary Obesity Centre in Rorschach in Switzerland, hypothesised that even one night’s disturbed sleep would produce a rise in levels of ghrelin, the hormone whose role in appetite regulation we looked at in Chapter 6.
To put their theory to the test, they separated ten normal-weight young men into two groups. One group they allowed to sleep undisturbed for seven hours and the other for just four and a half hours. Would this small amount of sleep deprivation change ghrelin levels? Blood tests showed that it did. Sleeping for only four and a half hours on a single occasion produced increases in feelings of hunger and in ghrelin levels in the blood.25
We conducted a study of our own in this area.26 In it, we also explored the extent to which sleep deprivation would affect a group of normal-weight young men and women. Our volunteers were invited to a hotel just outside London to take part in what they believed would be a series of team-building exercises. Because an early start was needed, they were checked in the night before and were divided into a Blue Team and a Yellow Team. At one a.m. a member of our research team hammered on the bedroom doors of the Yellow Team and told the bleary-eyed occupants to tackle a tough IQ test. This took about 30 minutes to complete, after which they resumed their disturbed sleep. But not for long – two hours later they were again roused from their slumbers, to complete a second IQ test. Once they had finished this they went back to bed and slept until 7.30 a.m., when both groups had to get up and come down to breakfast.
Throughout the night, using infrared cameras, we had watched the ‘sleep-disturbed’ participants to see just how effectively their normal sleep patterns were being disrupted. Taking into account the time they had spent struggling with the IQ tests, we calculated that, on average, the eight hours of sleep enjoyed by the Blue Team had been slashed to five for members of the Yellow Team.
After breakfast the following morning, both the well-rested Blue Team and the weary Yellow Team were handed bags filled with snacks on which to nibble throughout the day. Some were high energy-dense snacks, such as chocolates and biscuits, as well as healthier options including apples and low-calorie fruit bars. For the rest of the morning the teams then competed against one another in various games, which they believed to be the purpose of the study. What we were actually interested in was, of course, whether those deprived of sleep would impulsively consume more of the snacks high in sugar and fat than their well-rested rivals.
They did. The sleep-deprived Yellow Team consumed a third more calories than members of the Blue Team; losing sleep on even a single night can result in more impulsive eating the following day. Chronic sleep deprivation, therefore, will place an even greater burden on self-control, making weight gain more likely and obesity a stronger probability.
The dangers of not getting enough sleep in relation to obesity have been recognised by others. ‘Insufficient sleep (short sleep duration and/or poor sleep quality) has become pervasive in modern societies with 24/7 availability of commodities,’ explains sleep and obesity expert Jean-Philippe Chaput from the Children’s Hospital of Eastern Ontario. ‘Factors responsible for this secular decline in sleep duration are numerous and generally ascribed to the modern way of living (e.g. artificial light, caffeine use, late-night screen time, parental attitudes).’27
Dr Chaput highlights six ways in which lack of sleep contributes to future bouts of overeating. These are:
Children, too, can become more impulsive when their sleep is disturbed, especially if this is due to what is known as Sleep Related Respiratory Disorder (SRRD), which can cause them to snore or have difficulty breathing when asleep. A third of school-age children (35%) are reported to suffer from disordered sleep of whom three out of a hundred have SRRD and up to one in six (16%) are impulsive.28
To investigate the relationship between impulsivity and sleep disorders among children, Marilaine Medeiros and her colleagues from the Sleep Laboratory at São Paulo hospital studied 1,180 children, 547 of whom had poor sleep while the remainder slept normally.
‘School-age children with impulsive and dysfunctional behaviours show difficulties in falling asleep, refuse to lie down, present feelings of anxiety or fear at bedtime, stop taking a nap at an early age, and show nocturnal agitation, frequent nocturnal arousals and/or difficulties in falling asleep again,’ she reports. The aim of her study was to determine, ‘whether impulsivity is more prevalent in children with sleep disorders than in those without sleep disorders, and within which kind of sleep disorder.’29
The results were as Medeiros expected: children who slept poorly were also more likely to display impulsive behaviour, especially when their disturbed rest was due to impaired breathing. Consider the implications of this. If one of the ways that a child’s impulsiveness expressed itself were to be by overeating, then they could easily become trapped in a vicious circle; being overweight makes it harder to breathe efficiently, making it harder to sleep properly. Impulsive behaviour due to fatigue would then lead to further overeating, causing further weight gain and therefore making it even harder to breathe and sleep properly – and so on. If such a cycle starts in childhood, the probability is high that it will continue beyond adolescence and into adulthood.
Obesity is strongly linked with a variety of respiratory symptoms and diseases, including obstructive sleep apnoea syndrome (in which the individual momentarily stops breathing); obesity hypoventilation syndrome, asthma and decreases in lung volumes.30 The increased weight on the chest wall resulting from being overweight makes it harder to breathe in a relaxed and easy manner. These difficulties are compounded by greater resistance in the airways and a build-up of fat around the abdomen and intra-abdominal tissue, which impedes movement of the diaphragm.31
While impulsive eating is sometimes defined as ‘eating which takes place outside of regular meals or snacks’, as Michael Lowe of Drexel University and Kathleen Eldredge of Stanford University School of Medicine pointed out in 1993, many people’s lives include instances of this kind of eating without it becoming problematic.32
In fact, occasional impulsive snacks should not pose a direct threat to maintaining a healthy body weight. As we’ve already mentioned, the problems occur when we begin to use food to diminish other impulsive tendencies. Since we are constantly in environments that require self-control, including school, work, and social situations, it is increasingly important for us to identify situations that trigger the ‘need’ to eat energy-dense, nutrient-poor foods.
Yet, as we have shown, our food environment itself can contribute to this problem. The mere mention of a fast-food chain elicits impulsive behaviour, and our inhibitory control is tested virtually every time we walk into the supermarket – we are having to perpetually say ‘no’ to ourselves in the face of a mounting concentration of hyper-palatable foods. Whether in the grocery aisle, fast-food queue, or at a table in a restaurant, we are now required to put the brakes on our drive to eat with tremendous frequency. With such demands on our self-control coming so thick and fast, it’s easy to see how factors which erode it, such as insufficient sleep, can have tremendous repercussions.
Only by focusing on impulsivity as a key factor in the obesity epidemic can we begin to understand how to avoid, or perhaps control, behaviours that contribute to obesity.33 By improving sleep and exercise habits, and minimising stress, it is possible to increase reserves of self-control – which, as we have seen, is a finite psychological resource. Doing this, and also striving to identify and avoid situations which make us react in an impulsive way, will greatly increase anyone’s ability to control overeating.
Admittedly, ‘bolster your cognitive resources’ is hardly a match for more easily recalled public health slogans of the past such as, ‘eat less, move more’, or the ‘five a day’ plan. But it really does seem that we should be making cognition and impulse control a primary focus in the battle against obesity. When we begin to look at things from this angle we also gain a greater appreciation of the complexity of the issue. Obesity can lead to fundamental changes with the way a person perceives, experiences and desires food. There is, as shown in Chapter 7, a clear difference between obese and lean people in their responses to food-related imagery, with the former experiencing heightened anticipation and reduced impulse control.
The differences between lean and obese reactions to food-related imagery are so profound that some researchers have suggested that obesity could be considered a brain disease.34 But whether obesity is the result of brain impairment in the first place, or of over-nutrition contributing to subsequent cognitive problems, isn’t really the point. There is growing evidence to suggest that overeating can contribute to inflammation within the brain.35 In animal studies it has been shown that over time a high-fat diet leads to inflammation of the brain’s outer layer, the cortex, and of the hypothalamus.36 Such a diet also contributes to impaired insulin secretion and sensitivity.37 All of these disrupt an individual’s ability to guide their eating to match the needs of their body – rather they are bound to satisfying a deep-rooted desire for pleasurable experience. Thus, eating impulsively is the net result of significant biological changes that will perpetuate the cycle of overeating.
The truth is that we are not all on a level playing field when it comes to controlling our eating. The ‘greed’ which the obese are often accused of is a far more complex problem than that inaccurate and stigmatising label suggests.