Obesity is now considered a major health problem and is problematic to treat.
A number of causative factors for obesity have been defined such as genetic causes, metabolic disorders, eating patterns and behavior etc.
Despite identifying the factors, weight loss seems to be resistant to most treatments.
The solution offered for obesity is to eat less and burn more.
But lately, obesity is receiving attention from a psychological perspective.
Overeating is no longer considered as a matter of choice. Scientists are investigating overeating as a form of addiction.
Just like alcoholics ought to seek treatment, so should overeating be treated as a psychological disorder?
Two factors leading to this addiction could be hyperpalatability of foods and increased stress levels.
The taste of processed food items gives a feeling of pleasure which drives people to consume it in excess and reinforces the addictive behavior.
Due to the high availability of food people not only look at it as a means of survival but also a way to seek pleasure and to suppress negative emotions like stress and depression.
A study conducted in Washington University School of Medicine, St. Louis, Missouri investigated the similarities between obesity and substance abuse.
Two surveys were conducted, one in 1991 and 1992 and the other 10 years later in 2001 and 2002, where Americans were questioned about alcoholism in their family and their BMI was also recorded.
Results of the first survey showed no link between alcoholism and obesity.
However, the second survey demonstrated that adults with family history of alcoholism were 30 to 40% likely to be obese in comparison to those who had no such family history.
This tendency was greater in women (50% more likely) than men (26% more likely).
All factors to explain this phenomenon were considered, but researchers claimed that the biggest change that had occurred over the decade was the taste and nutritional content of foods.
This was the cause of overeating and obesity.
The risk of addiction was prevalent in families with a history of alcoholism and it was being manifested as food addiction.
The gender differences demonstrated that men included alcohol calories in their diet while women substituted it for other sources of energy.
To understand how basic survival instinct has turned into an obsessive disorder, we will proceed to taste of foodstuff presently available and the feeling they elicit on consumption.
Can we taste fat in our food? Is sugar addictive?
Progress in the current era occurs at a rapid pace and among the few things that are always going to be a man’s passion, food finds the number one position.
And the food industry is progressing in leaps and bounds just to make food items with different flavours and premium taste and quality available to the consumers.
Between 1970 and 2000, there was a 42% per capita increase in consumption of added fats and 162% increase in cheese relative to a mere 20% increase in consumption of fruits and vegetables.
Also, the per capita increase in soft drink consumption had increased dramatically.
Craving for sweet foods with high-fat content is a neurobiological feature that increases susceptibility for overeating.
Like the four most common taste perceptions like salty, sweet, sour and bitter our taste buds can also detect fats in food.
Molecules called non-esterified fatty acids are released for fat rich items which interact with taste receptor on our tongue and send signals to our brain which in turn releases ‘ feel good’ chemicals like dopamine.
Increased saturated fat intake is associated with greater BMI values. Low fat items do not elicit such taste thus making it hard to stick to low fat diets and increasing craving for fat rich food.
A study was conducted to compare the effect of flavors of low fat yogurt on parts of the brain that deal with the taste.
Participants were given plain low fat yogurt and low fat yogurt containing fat free aroma extract of olive oil.
The flavoured yogurt was found to increase blood flow in the pre-frontal part of the brain that deals with taste, for 30-120 mins after consumption.
This shows that the brain clearly recognizes the taste of fat such that even fat free extract of olive oil aroma can create a pleasure filled sensation.
We don’t need to emphasize much about sugar’s taste and the joy it elicits.
We all know what it feels like to sink our teeth in a molten lava cake or enjoy molten chocolate dripping from a chocolate croissant.
But what’s more interesting is that this taste can become addictive just like cocaine and other addictive drugs.
Animal models demonstrate the basis of sugar addiction and impairment of performance on withdrawal.
Most addictive drugs cause release of dopamine in part of the brain known as nucleus accumbens. This is the part of the brain that deals with motivation, reward, pleasure and reinforcement.
A study was conducted where rats were food deprived for 12 hours and then given a 12 hour access to sucrose solution and feed for 21 days.
Results demonstrated that rats released large amounts of dopamine every time they fed on sucrose solution and increased their quantity of consumption of sucrose.
Levels of acetylcholine, a neurotransmitter were lowered thus reducing appetite and increasing cravings.
Also, sugar deprivation produces the same withdrawal symptoms as that experienced by a person who is deprived of an addictive drug.
Having understood the basic idea of foods rich in sugar and fat we will now take a look at the different pathways involved in food addiction.
Why sugar and fat dense foods seem so appealing and addictive?
The brain has an area that is identified as a pleasure center (yes, that's correct).
It promotes activities that necessary for our survival such as eating and social activities.
The attainment of a particular feeling in this case pleasure is the ultimate motive. Loneliness fills you with a desire to communicate with others.
Similarly, hunger is a warning to shift from an undesirable condition.
Few elements that describe the connection between food addiction and the brain’s pleasure center are:
Is taste the only factor that motivates us to eat unhealthy food?
We trained to do activities that give us pleasure or those that avoid unpleasant outcomes.
The motivation system is the one responsible for this.
Food addiction results from a distorted motivation system where there is the loss of control over eating habits and reward seeking behaviour.
Are we conditioned to eat sugary foods?
This occurs when an originally neutral stimulus is associated with a reward.
Different cues trigger positive and negative outcomes and through the process of learning what’s good and what’s bad the outcomes get reinforced in our mind.
For example, eating chocolate elevates our moods, so the next time we are upset we try to grab the nearest chocolate flavoured item. Again its the pursuit of pleasure and reward involved.
The role of feel good chemical-Dopamine
This is the most important chemical as it mediates the same pleasure responses from the consumption of drugs or favourite foods.
It is released in anticipation as well as the consumption of food.
Dopamine is about feeling good and feeling rewarded and wanting to feel that way again.
The cue that triggered this feeling once is so strongly reinforced that dopamine is then released not only during food consumption but also at the sight and smell of food.
A good example to explain dopamine‘s role in food addiction is weight gain after smoking cessation.
Nicotine and food activate the same reward circuitry in the brain. So when people stop smoking they use food to generate the same pleasurable feeling.
Also, those who are deficient in proteins that activate dopamine have a tendency of doing something in excess so as to elicit the same pleasurable feeling a person with a normal level of dopamine activators would get.
They consume food in excess and utilise it as a self medication to boost a sluggish dopamine system. A reverse theory is that overeating on a long term reduces dopamine sensitivity in turn creating a desire to eat more food to compensate this feeling.
However, this effect ceases on the loss of weight.
A study conducted in 2009 demonstrated that women who lost weight as a result of surgery experienced an increase in dopamine receptors.
Negative eating behaviour was suppressed and they regained normal appetite.
Opiods- The dual role of an endogenous painkiller
These are another set of neurotransmitters which produce a rewarding effect similar to morphine and heroin.
Consumption of high sugar and high fat foods causes release of endogenous opiates which relieve pain and calm us down.
A review suggests the use of sucrose as a painkiller for infants below 18 months of age which could be due to the fact that it causes the release of endogenous opiates.
Use of medications that block opiate production are used to reduce consumption of high fat and high sugar food as well as cravings in people suffering from eating disorder.
Could our behavioural deficits be responsible for our eating habits?
Overweight and obese individuals tend to share personality traits with those who indulge in substance abuse.
Temperament and Character inventory scale is a list of personality traits used to describe a person’s behaviour. One of the traits listed in this is novelty seeking.
This is a good trait if exercised with caution but most of the times people go to extremes in order to experience the adrenaline or dopamine rush.
A character that is opposite to novelty seeking is self directedness where an individual uses self determination and will power to adjust to the situation and achieve the desired control.
There are no extremes involved in this.
Interestingly just like those who are dependent on alcohol and nicotine, overweight individuals score high on novelty seeking and low on self-directedness. This is a result of their lack of control on eating habits.
Children suffering from attention deficit hyperactivity disorder, conduct disorder, lack of attention and impulsivity have increased the risk of developing obesity.
These findings suggest that overeating has links to an individual’s personality traits as it is characterised by lack of self control when it comes to food consumption and failure to anticipate the harmful consequences such as weight gain and metabolic disorders.
Note:
In short consumption of sugary or fat-rich substances sends signals from our oral cavity to the brain’s pleasure center. This leads to release of feel-good chemicals and this memory is imprinted on our mind. So next time we are low or in a mood to seek pleasure we tend to crave or consume the very same food item. As time passes this reward system starts dulling so to boost you have to consume in excess leading to subsequent weight gain.
Are there any features that can help identify food addiction?
Diagnostic and Statistical Manual for Mental Disorders (DSM- IV) describes a list of criteria to define substance dependence. They can be used to draw a parallel in food addictive behaviour.
Prevalence of either two or three of these features over a year’s span can help determine an addictive nature.
These are the features that can help one judge whether their eating habit has turned into an addiction.
Tolerance
This occurs when the amount you eat may be in excess when compared to a normal individual but it does not give you a feeling of elation and that is why you eat even more in pursuit of that pleasure.
Withdrawal
Abstaining from high sugar and high fat food items plagues you with anxiety, depression and frustration.
This feature also occurs when you shift to a low carb diet, where lack of regular carb intake gives you a feeling of fatigue, dizziness and light headedness.
Cravings
We all have cravings on and off and they are indicators of a happy mind unless they manifest as strong urge to consume a specific type of food for which you are ready to go to extraordinary lengths and which can be rated as an irrational behaviour.
Desire to reduce consumption and relapse
Only when you feel you are eating out of proportion and you tend to feel guilty about it, thats when you attempt to stop this behaviour.
However, those who have lost control tend to relapse. These repeated cycles of quit and relapse contribute to poor treatment outcomes.
A study demonstrated that due to their inability to quit overeating 83% of the study participants regained their lost weight in 5 years.
Continued use despite of physical and psychological harm
Overeating can be considered as a negative behaviour when you continue consuming high calorie food despite of occurrence of harmful consequences such as unhealthy weight gain, development of diabetes and metabolic syndrome.
Excessive time utilised in procuring the substance and missing out on other events
Individuals suffering from eating disorders spend most of their time trying to satiate their food cravings and dealing with emotional consequences and stress linked with overeating.
Excessive food consumption reduces the amount of physical activity and also reduces engagement in social activities due to the negative image overweight individuals have about their body.
Prevention & Treatment for Food addiction
Just like substance dependence, when overeating manifests into an addictive behaviour it requires specialised attention and treatment.
Preventive measures can include educating children and their parents about healthy eating and the calorie content of food items.
Medications used to cure substance abuse are useful in controlling food addiction as both of them activate the same reward circuitry in the brain.
Behavioural treatment and counselling directed towards changing the attitude of such individuals, helping them find other ways to cope with stress and cravings and teaching them self monitoring are also essential for a secure recovery leaving no room for relapse.
Conclusion
I just cant stop eating. I have a great appetite. Or that’s the way I am.
These statements cant be taken lightly if you find your behaviour and attitude towards food intake a little disrupted.
To a certain extent, it is a matter of choice. Some people are not inclined to derive pleasure from food while some are.
But when you lose control, that is when overeating should be treated as an any other addiction.
Despite of the similarities in people who are involved in substance abuse and those who overeat, there are a marked number of differences which should be taken into account: -
Food consumption is vital for survival, overeating episodes can be occasional, roles of hunger and satiety hormones, the presence of metabolic disorders.
If all these conditions have been ruled out and overeating is observed to be influenced by emotions then overeating can be thought of as an addictive behaviour which demands adequate treatment.
Book reference: Eating Behaviour & Obesity - Shahram Heshmat, PhD