If you've ever tried to cut back on junk food, you may have realized that it is easier said than done.
We tend to get cravings... the brain starts calling for these foods.
Even though our rational, conscious mind "knows" that they are bad for us, some other part of our brain seems to disagree.
Some people don't have this problem and can easily control the types of foods they eat.
Other people don't seem to have any control whatsoever.
Despite their best intentions, they repeatedly find themselves eating unhealthy foods, even when they have previously decided not to eat them.
While some people think this is caused by a lack of willpower, the situation can be much more complicated than that.
The fact is... junk foods stimulate the reward system in the brain in the same way as drugs of abuse like cocaine.
For susceptible people, eating junk foods can lead to full-blown addiction, which shares the same biological basis as addiction to drugs of abuse (1).
There is a system in our brain called the reward system.
This system was designed to "reward" us when we do things that encourage our survival. This includes primal behaviors like eating.
The brain knows that when we eat, we're doing something "right," and releases a bunch of feel-good chemicals in the reward system, such as the neurotransmitter dopamine - interpreted by our brains as pleasure.
The brain is hardwired to seek out behaviors that release dopamine in the reward system.
The problem with modern junk foods is that they can cause a reward that is way more powerful than anything we were ever exposed to in nature.
Whereas eating an apple or a piece of steak might cause a moderate release of dopamine, eating a Ben & Jerry's ice cream is so incredibly rewarding that it releases a massive amount.
When people repeatedly do something that releases dopamine in the reward system (such as smoking a cigarette or eating a Snickers bar), the dopamine receptors can start to down-regulate.
When the brain sees that the amount of dopamine is too high, it starts removing the dopamine receptors in order to keep things "balanced." When you have fewer receptors, you need more dopamine to reach the same effect, which causes people to start eating more junk food to reach the same level of reward as before.
This is called tolerance.
If you have fewer dopamine receptors, then you will have very little dopamine activity and you will start to feel unhappy if you don't get your junk food "fix." This is called withdrawal.
Tolerance and withdrawal are the hallmarks of physical addiction.
Multiple studies in rats show that they can become physically addicted to junk food in the same way as they become addicted to drugs of abuse (2).
Of course, all of this is a drastic oversimplification, but this is basically how food addiction (and any addiction) works.
This can lead to various characteristic effects on behavior and thought patterns.
A craving is an emotional state, a desire to consume a certain food. It should not be confused with simple hunger, which is different.
Cravings sometimes seem to appear out of thin air.
We might be doing mundane things... watching our favorite TV show, walking the dog, reading... then suddenly a craving for something like ice cream appears.
Even though the cravings sometime seem to come out of nowhere, they can also be turned on by certain triggers, which are known as cues.
Walking past an ice cream parlor, the smell of pizza... these can turn on a craving.
But they can also be turned on by certain emotional states, such as feeling depressed or lonely. Emotional eating, anyone? A true craving is about satisfying the brain's need for dopamine. It has nothing to with the body's need for energy or nourishment.
When a craving occurs, it can start to dominate your attention. It can be very hard to think of something else and it can be hard to remember why on earth you had decided that you weren't going to eat junk food.
It isn't unusual to get cravings, most people do get them in some form.
But if you find yourself repeatedly giving in to cravings and eating junk foods, despite having previously made a decision not to, then that's definitely NOT normal.
For food addicts, these cravings can be so powerful that they cause people to break rules they had set for themselves (such as only eating unhealthy on Saturdays) and constantly overeat despite them knowing that it is causing them physical harm.
When you finally give in to the craving... then it's time for the reward, which is what all of this is about.
Now you eat that particular food until your brain has received all that dopamine that it was missing.
The more often you repeat this cycle of craving and rewarding yourself, the stronger it becomes and the more food you need each time.
Whereas 4 scoops of ice cream sufficed three years ago, today you may need 8 scoops to experience the same level of reward.
It can be almost impossible to eat "in moderation" when you are satisfying an addiction-driven craving.
That's why it is hopeless for people to just have a small slice of cake or a few M&M's. It's like telling a smoker to only smoke 1/4th of a cigarette to cut back, it simply does NOT work.
Over time, food addiction can cause severe physical and psychological problems.
Many people who have been struggling with food addiction for a long time can start hiding their consumption from others, can suffer from depression and have a severely broken self esteem.
This is compounded by the fact that most people don't even realize that they're addicted to food and simply think that they're weak and undisciplined.
Unfortunately... there is no easy solution to addiction. There is no supplement, mental trick or magical solution out there.
Whereas some people may need to learn how to control their consumption, it may be best for others to avoid these foods completely. If you have struggled with food addiction, then it may be best to seek professional help.
Psychiatrists and psychologists can help. There are also organizations like OA (Overeaters Anonymous), which anyone can join for free.
Binge eating disorder (which I think is pretty much identical to food addiction) is currently classified as an eating disorder in the DSM-V, the official manual that mental health professionals use to define mental disorders.
You can find some more info about food addiction on this page.