Below is an article from CNN that I read this morning. See my comments at the end!
CNN Article
Scientists have finally confirmed what the rest of us have suspected for years: Bacon, cheesecake, and other delicious yet fattening foods may be addictive.
A new study in rats suggests that high-fat, high-calorie foods affect the brain in much the same way as cocaine and heroin. When rats consume these foods in great enough quantities, it leads to compulsive eating habits that resemble drug addiction, the study found.
Doing drugs such as cocaine and eating too much junk food both gradually overload the so-called pleasure centers in the brain, according to Paul J. Kenny, Ph.D., an associate professor of molecular therapeutics at the Scripps Research Institute, in Jupiter, Florida. Eventually the pleasure centers “crash,” and achieving the same pleasure–or even just feeling normal–requires increasing amounts of the drug or food, says Kenny, the lead author of the study.
“People know intuitively that there’s more to [overeating] than just willpower,” he says. “There’s a system in the brain that’s been turned on or over-activated, and that’s driving [overeating] at some subconscious level.”
In the study, published in the journal Nature Neuroscience, Kenny and his co-author studied three groups of lab rats for 40 days. One of the groups was fed regular rat food. A second was fed bacon, sausage, cheesecake, frosting, and other fattening, high-calorie foods–but only for one hour each day. The third group was allowed to pig out on the unhealthy foods for up to 23 hours a day.
Not surprisingly, the rats that gorged themselves on the human food quickly became obese. But their brains also changed. By monitoring implanted brain electrodes, the researchers found that the rats in the third group gradually developed a tolerance to the pleasure the food gave them and had to eat more to experience a high.
They began to eat compulsively, to the point where they continued to do so in the face of pain. When the researchers applied an electric shock to the rats’ feet in the presence of the food, the rats in the first two groups were frightened away from eating. But the obese rats were not. “Their attention was solely focused on consuming food,” says Kenny.
In previous studies, rats have exhibited similar brain changes when given unlimited access to cocaine or heroin. And rats have similarly ignored punishment to continue consuming cocaine, the researchers note.
The fact that junk food could provoke this response isn’t entirely surprising, says Dr.Gene-Jack Wang, M.D., the chair of the medical department at the U.S. Department of Energy’s Brookhaven National Laboratory, in Upton, New York.
“We make our food very similar to cocaine now,” he says.
Coca leaves have been used since ancient times, he points out, but people learned to purify or alter cocaine to deliver it more efficiently to their brains (by injecting or smoking it, for instance). This made the drug more addictive.
According to Wang, food has evolved in a similar way. “We purify our food,” he says. “Our ancestors ate whole grains, but we’re eating white bread. American Indians ate corn; we eat corn syrup.”
The ingredients in purified modern food cause people to “eat unconsciously and unnecessarily,” and will also prompt an animal to “eat like a drug abuser [uses drugs],” says Wang.
The neurotransmitter dopamine appears to be responsible for the behavior of the overeating rats, according to the study. Dopamine is involved in the brain’s pleasure (or reward) centers, and it also plays a role in reinforcing behavior. “It tells the brain something has happened and you should learn from what just happened,” says Kenny.
Overeating caused the levels of a certain dopamine receptor in the brains of the obese rats to drop, the study found. In humans, low levels of the same receptors have been associated with drug addiction and obesity, and may be genetic, Kenny says.
However, that doesn’t mean that everyone born with lower dopamine receptor levels is destined to become an addict or to overeat. As Wang points out, environmental factors, and not just genes, are involved in both behaviors.
Wang also cautions that applying the results of animal studies to humans can be tricky. For instance, he says, in studies of weight-loss drugs, rats have lost as much as 30 percent of their weight, but humans on the same drug have lost less than 5 percent of their weight. “You can’t mimic completely human behavior, but [animal studies] can give you a clue about what can happen in humans,” Wang says.
Although he acknowledges that his research may not directly translate to humans, Kenny says the findings shed light on the brain mechanisms that drive overeating and could even lead to new treatments for obesity.
“If we could develop therapeutics for drug addiction, those same drugs may be good for obesity as well,” he says.
Dr. Court’s Comments
I agree with many of the statements in this article. I do believe brain chemistry plays a major role in why people make the wrong food decisions. Altering brain chemistry to improve symptoms of various problems is a large part of my practice. I disagree that it’s only the ‘fat’ in these foods that are addictive. If you feed a rat a fatty food like frosting it also must contain a lot of sugar and carbohydrate. How are we to know that these addictive behaviors were not a result of the carbohydrate in the food that the rats ate?
We must also consider that these rats were fed a steady diet of unhealthy fats as well. Avocado’s are high in fat. I seriously doubt that if you fed the rats avocado they would become addicted. It is the type of fat that is terribly important.
Carbohydrates and simple sugars have long shown to increase levels of serotonin and dopamine. It stimulates the feel good receptors in our brains. I think it’s a large leap to assume it’s the fat that’s the problem. Mainstream research wants to focus on fat as the culprit behind all disease, but it may not be. I think we would serve ourselves better if we took a step back and examined carbohydrates for their addictive traits. I think we’d see a much stronger correlation between simple carbohydrates and overeating than with fatty foods.
Consider that most fast food meals are a combination of unhealthy fat and simple carbs. Anecdotally, many people will tell you that they get a lift when they eat their daily McDonald’s value meal. For them it is a kind of ‘food fix’ that makes them feel good. This feeling of satisfaction and happiness, however, can be changed. Over time, by making the right choices of food people begin to lose their cravings for sugary/carby foods. I routinely put people on detoxification programs and initially the diet is hard for them because they crave starchy foods. It is a rare occasion that someone comes to me after a detox and tells me they craved nothing but fatty foods. It is almost always the carbohydrates that people miss.
After all, as human beings our physiology is geared to go after carbohydrates. They are the simplest and easiest way to get energy into our bodies. There is a primal drive to consume carbohydrates. Wouldn’t it make sense then that we might have some genetic predisposition to be “addicted” to carbohydrates? I believe so.
Dr.Gene-Jack Wang, M.D., the chair of the medical department at the U.S. Department of Energy’s Brookhaven National Laboratory, in Upton, New York had a great quote in this article. He said:
“We make our food very similar to cocaine now,” he says.
Coca leaves have been used since ancient times, he points out, but people learned to purify or alter cocaine to deliver it more efficiently to their brains (by injecting or smoking it, for instance). This made the drug more addictive.
According to Wang, food has evolved in a similar way. “We purify our food,” he says. “Our ancestors ate whole grains, but we’re eating white bread. American Indians ate corn; we eat corn syrup.”
You will notice the examples he cited were both of the refined carbohydrate type, not fat. In my practice this has always been the case. People are not addicted to fat. They are addicted to the simple carbohydrates that are so prevalent in Western diets. Think about it yourself; would you rather have a fatty pork chop or a carbohydrate laden doughnut? Almost everyone would choose the doughnut. Yes, I am aware doughnuts tend to be high in fat, but when you choose doughnut it isn’t because the fat appeals to you. It’s the sweet, fluffiness that pings your brain.
While I applaud this study for recognizing that there is more to weight loss than simple calorie-in calorie-out, I think the researchers may have come to the wrong conclusions. Next time they should try and isolate sugar from fat and test the hypothesis with more controlled variables.