Motivation and emotion/Book/2016/Overeating motivation

Motivations for overeating:
Why do we overeat and how can we curb it?

Multimedia presentation (3 min)

Overview

Humans eat for survival. The human body needs energy to enable both the brain and vital organs to function properly. Whilst the consumption of food is highly beneficial to the human body, excessive consumption of food has many drawbacks including physiological, social and cognitive issues. This chapter will discuss what factors motivates overeating and will explore some theories to curb overeating.

Figure 1: Over eating is the consumption of more food than what the body needs which can lead to lasting psychological and physiological issues such as obesity

What is overeating?

Overeating is the consumption of more food than the body needs. While everyone overeats from time to time, if this is a regular occurrence it can lead to lasting psychological and physiological issues. Often overeating leads to obesity which gives rise to health issues such as diabetes, high blood pressure and heart disease. Overeating is regarded as an eating disorder. Studies have shown a strong correlation between binge-eating and obesity (Smith et. al, 1998).

what are the risks of overeating?

Overeating may cause serious health problems both physically and mentally (Singh, 2014). Conditions may include heart disease, type two diabetes, sleep apnea and some types of cancers (Singh, 2014).

Hormonal influences

Leptin and ghrelin are important hormones to consider when looking into the reasons as to why many humans are unable to regulate food intake. Leptin is able to monitor hunger and ghrelin is responsible for meal initiation. Leptin and ghrelin are both active receptors in the hypothalamus. The hypothalamus signals the body that we are either hungry or full. If there is high levels of leptin in the bloodstream the hypothalamus will tell our body it’s full. If there is high levels of ghrelin the body will attempt to signal us to eat by making us hungry.

Leptin

The role of this hormone is to monitor satiety and influence our eating behaviours. Leptin is responsible for making us hungry. Leptin is stored in fat cells so the greater the fat mass of the individual the greater the amount of leptin. This is why many individuals in a caloric deficit (eating below the caloric intake required to maintain current body weight) may struggle with caloric consumption when dieting. When dieting many individuals may be deprived of leptin and as such will require greater self control as feelings of hunger will be amplified. The leptin receptors will activate the hypothalamus which will tell the body that it either does not have enough fat cells (which will result in hunger) or that it has ample fat cells (which will result in satiety). The body needs fat to survive so when it is largely deprived of food as a defence mechanism it will cause the individual to feel hungry. So a major reason that humans may be motivated to overeat may be caused by caloric restriction. Studies done into prolonged deprivation of food resulted in a rapid decline in leptin stores (Boden & Mozzoli, 1996). Early studies into fat mass produced a widely accepted theory that fat mass serves as the set point of energy balance, in which fat depots feedback onto the hypothalamus (Kennedy, 1953).

When questioning why people are overweight it may be confusing to look at leptin at first. We know that leptin is stored in fat cells so people with more fat should be able to regulate hunger quicker than people with less fat cells. However, on a study found on rats who were overweight many of these rats were in fact leptin resistant. As such they were not able to regulate hunger the same way as rats with regular hormones (Hervey, 1969).

Ghrelin

Similarly to leptin, ghrelin is responsible for making us feeling hungry. The difference between leptin and ghrelin is that increased levels of leptin will result in a suppression of hunger whilst an increase in ghrelin will increase hunger. Ghrelin is mainly produced in the stomach. If our stomach is empty our body will produce ghrelin, once our stomach is full our body will stop producing ghrelin (Cummings, 2001). The greater the levels of ghrelin, the hungrier we will feel. Levels of ghrelin are influenced by age, gender, BMI, growth hormone, glucose and insulin. Levels of ghrelin decrease with age, women have higher levels of ghrelin, and people with a higher BMI have lower levels of ghrelin. Further studies showed that ghrelin levels were increased when food related cues were not used (Cummings, 2004). However, in obese individuals ghrelin levels were found to be lower than that of an individual in the regular weight range. Some further studies may need to be done into how to limit levels of ghrelin.

Summary

Leptin:

• Stored in fat cells
• Greater the fat mass of the individual the higher the levels of leptin
• Less leptin means greater hunger

Ghrelin:

• Mainly produced in the stomach
• Responsible for making us feel hungry
• Levels of ghrelin are influenced by age, gender, BMI, growth hormone, glucose and insulin
• Ghrelin production stops when our stomachs are full

Practical application:

So we know that ghrelin levels rise when our stomachs are empty. The key to keeping hunger away would be to eat foods that are less calorie dense and keep our stomachs full. Consumption of foods such as fruits and especially vegetables will increase satiety levels and as such provide a major key to keep preventing overeating.

Figure 2: Obesity. Excess weight, especially obesity, is a major risk factor for cardiovascular disease, Type 2 diabetes, and some cancers

Influences on eating behaviour

Sometimes an individual's eating behaviours can be affected by external influences outside of conscious awareness. However, if an individual is fully aware of the impact of different influences they may be more aware of the choices they make. Different things such as social influence and who individuals eat with, TV shows including cooking shows and others that show consumption of food as well as food advertising may have a profound impact on an individuals eating behaviour.

Social

Food can often be at the forefront of a social event. Eating dinner with a loved one or family on a special event is common practice. However, in terms of caloric consumption, this can be problematic. A study on eating behaviours of men in the presence of both friends and strangers found that caloric consumption when eating with friends was much higher (DeCastro, 1994). It has been hypothesised that this may be due to the fact that eating with friends may skew the levels of appropriate consumption. This is due to eating for reasons of conformity rather than satiety (Herman et al., 2003). When eating around strangers social perception and how other individuals perceive the individual come into play. As such, the awareness of their eating behaviour will be heightened (Varatanian et al., 2007).

Advertising and Social Media

Over the past few years we have seen an increase in the number of television shows relating to food. Social media such as Facebook and Instagram are full of pictures and photos of what people are cooking and eating. Researchers have found that some individuals' cognitive processes allow them to self-restrain when exposed to food images. However, individuals who are motivated to overeat do not have the same self-restraint as their cognitive processes do not provide for this (Ouwehand & Papies, 2010). This suggests that individuals who are motivated to overeat are more sensitive to external stimuli such as seeing food advertised on television or social media and reacting to the stimuli by overeating. However, research on the effect advertising snack food has on individuals suggests that it increases food intake for all people (Harris et. al, 2010). An interesting factor from the studies was that when weight loss messages were advertised, individual who were dieting where less likely to eat the food provided (Ouwehand & Papies, 2010).

Cultural Influences

Cultural influences can play a major part in an individuals eating behaviour. It can influence the type of food people eat but most importantly how much people eat. In some cultures being overweight can be seen as a sign of wealth and good health. In other cultures being overweight can be a sign of laziness. It is important to see how the cultural influences can influence the likelihood that we overeat. These cultural influences can also influence motivation to eat. In some cultures overeating could be conforming to social norms. In other cultures there may be pressure among individuals to look a certain way. This can be influenced by the media and the ideal for that culture. This may have skewed the body image perception in certain cultures. These have been shown to result in eating disorders in many individuals in the Western World (Williams & Germov, 2008).

Learnt Behaviour

Overeating can result from learned behaviors. Baumeister et al (1994) found that individuals can get into a pattern of continuing to do a particular thing over and over. An example of this is an individual commences having a piece of cake every day at morning tea. The motivation is that is became part of a habit or ritual that is repeated every day and there is no thought process on whether the individual is hungry for the cake or not. The individual consumes the cake without responding to physiological hunger and satiety cues. It becomes a learnt behavior. In order to curb this motivation for overeating the individual needs to break the habit and this could be done through introducing a different habit which did not involve the consumption of food.

Summary

Social

• Eating food is a common social event
• We consume more in a social setting
• Consumption is amplified when we eat with friends
• We consume less when eating with strangers

Advertising

• Individuals who are motivated to overeat are more sensitive to external stimuli such as seeing food advertised on television
• Exposed to food on social medias
• When weight loss messages were advertised, individuals ate less

Cultural Influences

• Culture can influence how much we eat
• In some cultures being fat has a positive stigma
• Skewed perception of the ideal body by media has led to eating disorders in the western world

Learnt Behaviour

• Overeating can result from learned behaviors
• In order to curb overeating the individual needs to break the habit and this could be one through introducing a different habit which did not involve the consumption of food.

Practical application

When eating out socially we tend to let our guard down due to a lack of awareness and conformity. Knowing this we can change our eating habits because we know that we are going to eat a little more and eat less than we normally would before and after eating socially to cater for this. With advertising and social media it is important to become more conscious of what we are seeing and the affect that it has on us is a crucial coping mechanism. If we are aware that advertising and social media are influencing our eating habits we can become more conscious in our decision making when it comes to food. From learnt behaviour we know that an introduction to a new habit unrelated to food can help to curb overeating.

Relevant theories

Goal Conflict Theory

Goal conflict theory was devised by Stroebe (2008). Stroebe devised the theory upon two different groups. The first group was restricted eaters and the second unrestricted. The restricted eaters were more diligent with consumption and had the goal of either maintaining body weight or losing weight. The unrestricted took a more relaxed approach. The theory was formed on the basis that individuals must find balance between enjoying foods whilst not overeating. Going too far either way could lead to severe restriction or over consumption.

Studies into the 2 different groups found that the restricted eaters were more susceptible to over-consuming foods that tasted good. This is due to the nature of the theory that explains that when presented with palatable food, the restricted eater is in conflict. The major take away from this theory is finding balance. Eating foods in moderation and finding a happy medium rather than restricting oneself from palatable foods will result in less conflict. Less conflict means less anxiety and less susceptibility to overeating.

Restraint Theory

There have been a number of studies examining how to curb overeating. Dieting or Restraint theory is one treatment which has been examined as a way of curbing overeating. Restraint theory concentrates on cognitive control on food intake. It centers on the reducing food intake. Various methods to reduce food intake (diets) appear in the press every day. However studies have found that trying to reduce your food intake actually increase the likelihood of overeating (Herman and Mack 1974). Ruderman and Wilson(1979) found that people who dieted were more likely to increase their weight rather than reduce it. This is because when people restrict their food intake they tend to become extremely hungry and this results in them wanting to eat more to satisfy their hunger (Polivy 1996).

A study conducted between 1944 and 1945 by Dr Ancel Keys at the University of Minnesota involved bringing people to near starvation and then re-feeding. The study found that the participants developed physical, psychological and behavioral issues that continued even after the experiment finished. In fact 6 month after the experiment, most of the participant gained their pre-experiment weight plus an additional 10%. A number of other studies have concluded that restraint theory results in loss of control, making poor choices and overeating (Vitousek 2004; Polivy and Herman 2006; Polivy 2008).

Summary

Goal conflict theory

• Conflict between maintaining or losing bodyweight and eating tasty food
• Must find balance between enjoying foods whilst not overeating
• Eating foods in moderation is key

Restraint Theory

• Dieters were more likely to increase their weight rather than reduce it
• Trying to reduce intake increases likelihood of overeating
• People who restrict their food intake tend to become extremely hungry and overeat

Practical application Both these theories outline the importance of not restraining oneself to extremes when it comes to eating. Over restraint can often lead to a harder rebound and a poor relationship with food. With this knowledge in mind having a moderate diet that is not overly restrictive will lead to better results when it comes to overeating.

Emotional Eating

Stress

Stress has long been regarded as a trigger to overeating. The literature on stress related eating examines two models, the General Effects and the Individual Differences model (Greeno & Wing, 1994). The General Effect Model basically says that if individual suffers from stress they will overeat. The Individual Difference Model suggests that there are clear influences on an individual that will determine whether they overeat or not. One hypothesis that has been tested is that obese individuals are more likely to overeat as a result of stress than normal weight people.

In 1957 Kaplan & Kaplan came up with the Psychosomatic Theory of Obesity. This theory is that food is used as a defense mechanism when dealing with the negativity of stress. It also suggests that obese individuals overeat in the face of stress while normal weight individuals engage in other coping strategies (Faith, Allison, & Geliebter, 1997). Therefore, stress can be a motivator to overeating. It is a coping mechanism. Treatments to curb this type of overeating include behavioural and cognitive treatment.

It is interesting to note that short term stress usually reduces the appetite. This is because the hypothalamus produces corticotrophin-releasing hormone, which reduces appetite. During this process the body also produces adrenaline which causes the body’s fight-or-flight response. But if stress is long term the adrenal gland release a different hormone called cortisol. Cortisol increases an individual’s appetite and the motivation to eat. If the cortisol level stays high this increases the individual motivation to eat.

Depression

Individuals suffering from depression may also be motivated to overeat. Depression may result from an emotional disturbance or it may be as a result of a brain injury. Depression could motivate overeating or undereating. When it motivates overeating in some instance it results in carbohydrate cravings. Studies have indicated that carbohydrate cravings are related to a need for serotonin. This is why antidepressants work to increase serotonin.

The function of the lateral hypothalamus in the brain is significant for eating motivation. Its nerve activity has the main connection with changes in eating patterns. Researchers have reported that injuries in this part of the brain can lead to major changes in appetite. This could motivate people to overeat without regard to what they are eating.

Summary

Stress

• Trigger for overeating
• There are clear influences on an individual that will determine whether they overeat or not.
• short term stress usually reduces the appetite.
• Cortisol increases an individual’s appetite and the motivation to eat
• If cortisol level are high it will increase the individual motivation to eat.

Depression

• Studies have indicated that carbohydrate cravings are related to a need for sertonin.
• Function of the lateral hypothalamus in the brain is significant for eating motivation
• Injuries in the brain can lead to major changes in appetite

Practical application

When placed in a stressful situation becoming aware that feelings of hunger may not be due to lack of satiety. Rather being aware that a raise in cortisol levels are present and this can increase motivation to eat.

Depressed individuals should not look to food as an outlet for serotonin. Whilst it may provide temporary comfort, feelings of guilt or shame may arise from overeating. These feelings will only enhance feelings of depression and decrease feelings of self esteem or self worth.

Conclusion

It is important to consider the physiological and psychological variables that may trigger individuals to overeat. If individuals are aware of how their body is triggering they are better able to control and be aware of their eating habits. Making better choices with food in regards to choosing more nutrient dense foods will result in better physiological responses in regards to the body monitoring of satiety and hunger, as well as overall health.

The key to controlling overeating is to take a moderate approach. Studies have shown that taking an extreme approach can be beneficial in the short term but can also develop a poor relationship with food. This poor relationship could include stress and anxiety when eating out socially or even over indulging when placed in an environment when there is stress and temptation. Eating emotionally whilst providing instant gratification can yield further long term emotional problems.

References

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External links

https://www.youtube.com/watch?v=wOPl8P2S-Lw} By Jamie Oliver, 7 August 2013