Save the Children is to be applauded for reminding us all of one of the most extraordinary and humiliating aspects of living in the modern world: child hunger. Drawing a parallel with the fight to abolish slavery, the Ghanaian philosopher Kwame Anthony Appiah recently asked what future generations will condemn us for. One sure candidate is the needless human carnage wrought by hunger. Some 850 million people (one in eight of the world's population) go to bed hungry every night. Many of them are children, for whom early hunger leaves a lifelong legacy of cognitive and physical impairment. The human and economic waste is horrifying.
Such hunger is not due to a shortage of food – globally there is enough to go round and if (a big if) we make the right decisions now, we can continue to feed the world despite population growth and climate change. By some estimates, stopping the waste of food after harvest due to poor storage or transport infrastructure, and then in our own kitchens, could free up half of all food grown. The number of overweight and obese people in the world, suffering their own health problems, including a sharp rise in heart disease and diabetes, is roughly equal to the number of hungry people. That highlights one of the underlying causes of hunger – extreme levels of inequality, both within and between countries.
Ending hunger is entirely feasible (indeed, once achieved, the only question will be why it took us so long). It requires action at several different levels. At a national level, progressive governments in Brazil and Ghana have shown how to cut hunger sharply, through cash transfers to poor people, raising the minimum wage and investing in smallholder farmers (especially women), who both produce food, and are some of the poorest and hungriest people in the Alice in Wonderland world of a brutally unfair farming system.
That focus on national decisions and national politics highlights how fast the world is changing. In many cases, aid is no longer the main story – countries like India, growing at 8% a year and with a mushrooming middle class, need to take responsibility for their hungry masses, introducing proper taxation and effective social services to end hunger and malnutrition. Oxfam is working with people's organisations within the country to bring that about. Elsewhere, though, international food aid remains essential, but should be improved, for example by ending the waste and delay of transporting food thousands of miles from donor countries and giving cash instead.
Beyond supporting aid for food and agricultural investment, what else can we in the well-fed countries do? Start by putting our own house in order. The rich countries are part of both the solution and the problem. Europe and America's push to reduce their dependence on imported oil and gas has led them to introduce targets and subsidies for biofuels, but these compete directly with food production, forcing up prices for poor people. Rich country greenhouse gas emissions are driving climate change at a pace that outstrips even the most pessimistic projections of the climate modellers, and there are few signs of governments agreeing (still less achieving) the kinds of reductions needed to avoid catastrophic temperature rises that will particularly harm tropical agriculture. We urgently need an international effort to find a way to feed the planet's growing population without destroying its ecosystems, yet current investments are feeble.
Hunger is both a cause and a symptom of poverty. Damaged bodies and brains are a moral scandal and a tragic waste of economic potential. That hunger exists at all shows the urgency of redistributing income and assets to achieve a fairer world. Providing the additional calories needed by the 13% of the world's population facing hunger would require just 1% of the current global food supply. That that redistribution has not already taken place is truly something to be ashamed of.
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This is a guest post by Raea Rasmussen, Williams College Class of 2015
In the United States today, 68.8% of people are either overweight (BMI of 25-29.9) or obese (BMI of 30+) (NIH, 2012). This means that only 31% of people are either of a healthy weight or underweight. Obesity poses a serious health risk as it is strongly related to serious illnesses such as heart disease, stroke, type 2 diabetes, and cancer, and incurred 147 billion dollars in medical costs in the US in 2008 (CDC, 2014). In an attempt to combat this trend towards overweightness, many individuals diet. On any given day, an estimated 25% of men and 45% of women in America are dieting (Eating Disorder Hope, 2014). And yet, 95% of dieters will regain this lost weight within 1-5 years (Eating Disorder Hope, 2014). Why do we have so much trouble keeping our weight down?
Harvard evolutionary biologist Daniel Lieberman explains that humans evolved to crave sugar for energy in times of scarcity and also to support our large brains (2012). However, in modern days, there has been no scarcity of sugar. The result is that the excess sugar available to us is converted into fat, leading to an obesity epidemic. But regardless of the greater availability of sugar and food products in general, why do we continue to eat after our bodies have acquired enough energy to sustain us? Is it for pleasure? Is it out of boredom? We argue that obesity is not caused by physiological hunger, the purely physical intake of high-calorie meals at fast food restaurants, or eating excessively when you are full. Instead, hunger has psychological causes, and we often feel hungry even with full stomachs.
Three types of cues
People are only hungry when their stomachs are empty, and become satiated when it is full: false. The physiological cues associated with an empty stomach that tell us to eat are referred to as internal cues. However, even when these cues are not present, external cues can induce hunger as well. These external cues may broadly be divided into two categories: normative cues, such as portion size, that indicate appropriate levels of consumption, and sensory cues, such as smell or taste, that refer to the hedonic value of food (Herman & Polivy, 2008). Schachter (1968) originally proposed that obese individuals are more responsive to external cues and less responsive to internal cues than others, and therefore are more likely to eat even when their bodies are not sending them the physiological signals to do so. In an updated model, Herman & Polivy (2008) suggest that while normative cues affect everyone, obese individuals are more likely to be strongly affected by sensory cues than others.
External sensory cues
Sensory cues defy the simple concept that we eat when we are hungry and stop eating when we are full. Lambert et al. (1991) conducted an experiment in which they gave either hungry or satiated subjects one of three types of sensory cues or no stimulus, and compared their desire to eat chocolate before versus after the stimulus. The different sensory cues included taste (trying a piece of chocolate), sight (viewing a photograph of chocolate), and cognition (reading a description of chocolate). They found that the presentation of sensory cues significantly increased participants’ desire to eat chocolate, and that participants consumed more chocolate regardless of their state of hunger or the type of stimulus presented. This indicates that a variety of external sensory cues can influence people to consume food, even if they are not hungry.
External normative cues
External normative cues have also been shown to influence how much we eat. Generally speaking, people have the tendency to finish the food on their plate. It is perhaps not surprising then, given our huge portion sizes in America compared to France, that the obesity rate in America is 35% (CDC, 2014) while in France it is only 7% (Davis, 2003). Our candy bars are 41% larger, our soft drinks are 52% larger, and even our cartons of yogurt are 82% larger than those products in France (Davis, 2003). Wansink et al. (2005) conducted an experiment demonstrating that the normative cue to finish your plate (or bowl in this case) can lead participants to eat more without realizing, and without even feeling more sated afterwards. Participants were either given a normal bowl of soup or a bowl that self-refilled imperceptibly as the contents were consumed. Participants with the refilling bowls ate 73% more soup than those with the normal bowl, but did not believe they had eaten more and did not indicate that they felt fuller than the other group. This shows how satiety is not necessarily defined by how much we eat and how full our stomachs are, but rather by consumption norms and expectations.
Memory for recent eating is another normative cue that influences whether or not we eat. For example, Rozin et al. (1998) conducted an experiment with amnesic patients in which they measured whether or not they would consume multiple meals in succession. The patients had no explicit memory for events that occurred more than a minute before, and specifically could not remember if they had just eaten a meal. Rozin et al. (1998) proposed that the primary reason for determining when to begin a meal is based on when an individual had eaten their last culturally defined complete meal. Therefore, if participants could not remember eating, they would readily consume another meal if presented to them. In fact, their results demonstrated this phenomenon: the amnesic participants consumed a second lunch offered 10-30 minutes after the first, and began to consume a third lunch offered 10-30 minutes after the second. These results are despite the fact that, presumably, the participants’ stomachs were physically full after each meal. This demonstrates that the urge to eat is not just related to physiological urges, but also to normative cues. Higgs (2012) showed similar effects in the typical, non-amnesic participants. When participants were asked to think about what they had eaten for lunch, they ate less than if they were asked to think about what they had eaten for lunch the day before or received no cue at all.
In addition to sensory and normative cues, social facilitation is another type of external cue that can influence our eating behaviors. Redd & Castro (1992) found that when instructed to either eat alone, with other people, or eat as they normally would (with the choice of either eating alone or with others), undergraduate psychology students consumed more water, sodium, food, and alcohol when instructed to eat with others than when instructed to eat alone. In addition, when eating as they normally would, those participants who ate with others consumed 60% more than those who ate alone. Therefore, eating with others can cause individuals to consume more food than they would otherwise.
As we can see, external cues are extremely influential in determining when we feel hungry and how much we choose to eat. Despite the principal role external cues play, we are often unaware of these cues. For example, in a study in which pairs of participants were given a chance to eat, they took cues from each other, so that if one partner ate more, the other did too (Vartanian et al., 2008). However, participants did not indicate that the amount they ate was influenced by their partner’s behavior, but rather attributed their intake to taste and hunger. Thus, a lack of awareness of external factors may make it difficult to attenuate these influences on excessive food intake.
Other psychological factors may also lead us to eat unnecessarily. Stress in particular has been shown to drive us to consume more food. In a study of female participants only, Groesz et al. (2011) found that greater reported stress was associated with participants’ drive to eat, as measured by feelings of hunger, binge eating, disinhibited eating, and ineffective efforts to regulate eating. Kandiah et al. (2006) found that stress produced a change in appetite in 81% of participants, and that 62% of these participants experienced an increase in appetite. Those with an increased appetite were also more likely to choose sweet or mixed foods such as desserts or burgers. Interestingly, while 80% of participants reported eating healthily normally, this number dropped to 33% when they were stressed. This increased drive to eat and to eat unhealthily may explain why stress may contribute to obesity.
Ironic effects of a restricted diet
While we have explored many of the potential psychological contributions to overeating and obesity, the question still remains as to why obesity is so much more prevalent among Americans than people of other nationalities. One possibility is that there is a fundamental difference in Americans’ attitudes towards food. While Americans think about food in terms of a biological, nutritional, and health-related need, consider it a material good, and use it as a reward, French people associate food with pleasure (Werle et al., 2012; Ochs et al., 1996; Rozin et al., 1999). Werle et al. (2012) found that while Americans associate unhealthy food with tastiness, French associate healthy food with tastiness. In addition, while Americans think of eating healthy versus unhealthy food in terms of ‘right’ and ‘wrong,’ French typically associate food with pleasure, part of social life, sharing, and health (Werle et al., 2012).
This American classification scheme in combination with the common desirability for ‘the forbidden’ may help to explain why we associate unhealthy foods with tastiness. Unfortunately, this association may result in less healthy eating choices, especially given that we use food as a reward—we may reward behaviors with unhealthy food. Werle et al. (2012) suggest that emphasizing the pleasure of eating and decreasing the guilt associated with consuming food may be more effective than the calorie-counting, food-shaming culture we have in America today. Ironically, allowing oneself to eat yummy foods might it easier to eat less.
This ironic effect of restriction seems to be passed on to children by their parents. One study examined non-Hispanic white girls aged 5-9 whose parents either did or did not restrict their access to food. The girls whose diets were restricted showed higher increases their tendency to eat in the absence of hunger than were girls whose parents did not restrict their eating (Birch, Fisher, & Davidson, 2003).
Overeating and obesity are not only costly problems financially, but also pose a serious health risk to hundreds of millions of Americans. In evaluating the nature of the problem, it is important to understand that we do not simply overeat when our stomachs are full. Rather, the manner in which we determine whether or not we are hungry, whether or not we should eat, and what we should eat, is much more complex. Furthermore, the extent we eat is strongly influenced by psychological factors such as sensory cues, normative cues, social facilitation, memory of our past meal, stress, and our cultural attitude towards food.
Through an extensive examination of these psychological processes, perhaps we can work towards a more effective solution to combat obesity—not calorie-counting just to gain the weight back within a few years, but understanding the underlying psychological cues and using this knowledge to help us identify when our stomachs are empty and when they are full but our minds just think they are empty.
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