Why Diets Fail (Because You're Addicted to Sugar) (11 page)

What happens if a drug addict does not have access to the drug? Withdrawal can ensue, and the addict may experience feelings of depression and anxiety, along with other possible unpleasant side effects, including nausea. Withdrawal can also be apparent in response to food. When one is dependent on excess sugars, feelings and symptoms that are similar to what one sees during drug withdrawal (such as depression, headaches, anxiety, and irritability) can arise.

In an attempt to alleviate these symptoms and satisfy his cravings for the substance, the addict may resume using the substance, despite knowing the consequences associated with this consumption. With food, cravings can be sparked by an emotional response, a habit (such as if you were accustomed to having a piece of cake after dinner most nights), or cues or reminders of a favorite food. When these events occur, our brains are reminded of how good we used to feel when eating these foods, and how that good feeling could help to ameliorate the negative feelings we face during the withdrawal phase.

All of these behaviors and conditions—bingeing, craving, withdrawal—originate in the brain. As it turns out, the areas of the brain that regulate and experience pleasure, whether that pleasure is in response to food or drugs of abuse, is very similar.

The Addicted Brain

The human brain is a complex organ with many different working parts. At any given moment, the different regions of our brains are communicating so that we can make sense of, and respond to, our environment. Different parts of our brains work together to sense stimuli, control our actions, and tell us when we need something.
Certain regions are responsible for motivation and control, feelings of pleasure and reward, and memory. These regions of the brain can sense information and communicate with each other via messengers called
neurotransmitters
. Neurotransmitters travel to, or stay away from, certain regions of the brain in response to events happening in the world around us and within our own bodies. For example, when we smell the aroma of a freshly baked apple pie, we might recall what it tastes like, decide that we want a slice, and go over and get a piece. In order for this sequence of events to occur, specific pathways in the brain need to be activated to initiate the memory of the taste of apple pie and motivate us to physically walk over to the pie and then cut ourselves a slice. Similarly, once we eat the pie, a cascade of events must occur in our brains that allow us to feel pleasure from the food, and signal to us when we have had enough and should stop eating. The figure on
this page
shows some neurotransmitters in the brain that play important roles in addiction and food intake.

When someone is addicted to a drug of abuse, these neurotransmitters are affected in key brain regions. In particular, neurotransmitters in the reward-related brain regions are influenced.
Dopamine
is a neurotransmitter that has many roles in the brain, such as being released in response to stimuli and situations that cause pleasure: having sex, eating certain foods, and consuming drugs and alcohol. We experience pleasure, in part, because of elevated dopamine levels, and thus we are motivated to continue enjoying these experiences and sensations. In other words, the pleasurable feelings that result from the release of dopamine also serve to reinforce the behavior.

Does dopamine act alone? That is, is dopamine the only neurotransmitter that plays a role in addiction? Not at all; in fact, there are a number of other chemicals in the brain that are involved in addiction. The other neurotransmitters depicted in the figure above, serotonin, opioids, and acetylcholine, also have roles in drug addiction and food intake or satiety (fullness), and there are numerous others that are not shown that also have contributory roles in these processes. However, our focus here is on dopamine, as it is one of the primary neurotransmitters involved in addiction, and it also plays an important role in the regulation of food intake. We need dopamine in order to motivate us to eat, to indicate whether food is safe to eat, and to tell us whether the food tastes good. If we didn’t have dopamine, we wouldn’t have the desire to eat (and that goes for all types of food, not just junk foods).

Now, you might be thinking that drugs and foods like sugars are clearly very different. And you’re right; there is no doubt that food and drugs of abuse are very different in important ways.
However, the brain reward systems that are responsible for making drugs of abuse so addictive are actually the same pleasure systems that are activated by the foods we eat. So to our brains, the difference between drugs and some foods might not be so obvious.

The Addictive Nature of Food

One way in which foods and drugs of abuse are very different is that we need food to survive, but we don’t need drugs of abuse. Interestingly, however, the survival value of food is actually one of the factors that may contribute to its addictive potential. Food is one of our basic needs, and thus our brains evolved to make us like the taste of food and seek it out when we are hungry. Some people will do some extreme things when they are faced with severe hunger (for example, theft or cannibalism), which underscores what a powerful motivator food can be. We need to eat and mate to survive as a species, so our clever brains make us enjoy those activities. That enjoyment occurs through the activation of the same reward systems that are activated by drugs of abuse. So, drugs of abuse actually hijack these primitive brain systems that reinforce natural behaviors, such as feeding. Based on this, the brain circuitry is certainly in place for foods to also become addictive, just like drugs.

Another basic factor that separates food from drugs of abuse is its availability. We have to eat food to survive, so it is all around us. Obviously, this makes drugs of abuse much different from the foods and drinks that we have available to us almost everywhere we look. In addition, there are billboards, commercials, and signs everywhere advertising food, many of which depict the types of foods that people often crave. Fortunately for drug addicts, the cues associated with drug use are less commonly seen.

Also related to availability is the fact that there are negative consequences associated with using drugs that are not seen when people abuse food. You can be arrested, fined, and jailed for buying, selling, and carrying some drugs. You can even be arrested for having an open container of alcohol in your car while driving. There is a social stigma associated with using drugs, and this is not normally the case with food (although there is a social stigma that sometimes comes with eating when an individual is overweight). So when it’s proposed that certain foods with a high concentration of sugar or fast-digesting carbs in them may be addictive, what does this mean?

Well, certainly humans crave food. We need it to survive. But just because we crave these sugary, high-carb foods does not prove that we are addicted to them. Humans, especially when very thirsty, crave water, but nobody would claim that anyone has an addiction to water. If you left a person in the desert long enough and offered him water or even just showed him pictures of water, you would probably see a release of dopamine in his brain. Exhibiting this response is not sufficient to say that something is addictive. Addiction is something fundamentally different.

The New Science of Food Addiction

So far, several reasons have been discussed that suggest why food is a natural candidate to move into the addiction category. In fact, it was drug addicts (alcoholics, in particular) who first provided the hint that food intake can be an important part of the addiction cycle. In the Alcoholics Anonymous manual it says, “We now find that it is wise to eat balanced meals at regular hours.… The reason for this advice is simple. If we are undernourished and lack rest, we become irritable and nervous. In this condition, our tempers get out
of control, our feelings are easily wounded, and we get back to the old and dangerous thought process.”
²
This quote underscores what scientists have gone on to show repeatedly: disruption of the feeding cycle can contribute to addictive, drug-seeking behaviors. Since then, scientists have refined this notion and have shown that intake of certain foods, like sugars, are associated with alcohol intake.
³

Researchers have largely looked at studies of food addiction as a way to possibly understand why there has been such a sharp rise in the rates of obesity over the last several decades. The fact that people across the globe are gaining weight rapidly cannot be explained by alterations in our genes or some sort of evolutionary change, as these changes don’t happen that quickly. Instead, many suspect that the increase in obesity is due to an environmental change. Our modern-day food environment is filled with opportunities to get quick and easy access to food, which can be a good thing, but unfortunately these convenience foods tend to be highly processed, dense in calories, and high in sugars. The ease and convenience of such foods lure us to eat them or feed them to our families, but when we consume them in excess, we can experience increases in body weight.

Over the past few years, more research has investigated the idea that some foods might be addictive. The data suggest numerous overlaps between drug addiction and obesity, both in terms of behavior and brain changes. For example, studies show that when obese people are shown images of foods they desire, their dopamine system is activated as if one were showing drug paraphernalia to a drug addict. It doesn’t take scientific studies to tell us this; anyone who is overweight and has gone on a diet in an attempt to lose weight can relate to the compulsion and desire to eat certain foods. That is one reason why adherence to diets is so poor: people find it almost impossible to give up the foods that they love, which are usually high in calories and contain a lot of sugars.

WHY SUGARS?

Although research has been assessing how food in general might be addictive, the foods that seem to be posing the biggest problem are not healthy food choices like leafy greens and lean meats. Rather, people with problematic eating patterns tend to consume a lot of foods made up of carbohydrates and added sugars. For the sake of brevity, we use the term
food addiction
in this book. This is meant to refer specifically to dependence–like relationships with highly palatable foods, such as those high in sugars, not just any type of food. Many people also report that they find it difficult to abstain from carbohydrates, and some feel compelled to eat them.