Peter McKnight's article ("Sweet on sugar"), in the second of the six-part series on sugar (se previous blog entry), weighs in on the question of whether or not sugar is addictive. He points out that the topic attracts a lot of people, especially professionals in the medical business. And the topic of addiction is found on all fronts: shopping, exercise, video games and so on. This is because the definition of addiction is vague - it could apply to anything. But the world of psychiatry and psychology have identified underlying aspects such as changes in brain chemistry. To illustrate, if sugar is addictive, one can simply demonstrate that it produces those underlying elements (changes to brain chemistry) that identify it with addiction.
McKnight refers to a "comprehensive" study produced by a team of psychologists at Princeton University led by Bart Hoebel which is often cited as proof that sugar is addictive. This was a study that divided rats into several groups. One group (experimental) had 12 hours of free access to their daily food with sugar water, then deprived them of anything for another 12 hours. This group was compared with three other groups - rats who always had access to the food and sugar; rats who had access only to food (no sugar water), either all the time or in periods of 12 hours. The experimental group did display behavours that were in tune with the three stages of addiction according to the American Psychiatric Association - bingeing, followed by symptoms of withdrawal - anxiety & depression - and lastly, craving characterized by pressing the lever that dispenses sugar water more readily than those of the control groups. Changes to brain chemistry in a specific area (nucleus accumbens) were also found among the experimental group - increases to dopamine took place, similar to that of the effect of morphine and cocaine. So, addiction is real with respect to the consumption of sugar. So what? McKnight points out that critics like neuroscientist David Benton argue that music, humour, winning a game, smiling faces and so forth have similar outcomes - the release of dopamine. Benton argues that the dopamine becomes "habituated" - hence, it subsequently releases less and less dopamine. What is important is that destructive drugs never produces "habituation." A drug like morphine is alien to our bodies, carbohydrates, not so. But the study did show that the experimental rats never got habituated - the control group did not display signs of addiction. Hoebel admits that addiction to sugar is possible if we approach it like the experimental group. McKnight concludes that, since most humans do not eat that way, then "the risk of developing an addictive to sugar is effectively nil."
What McKnight fails to grasp is that obese people are not like slim people; diabetics are not like non-diabetics. McKnight says that those who eat naturally won't become addicted to sugar. The answer needs to be qualified - in the short term - because what McKnight fails to understand is that the problem is not sugar but carbohydrates; starches, like sugar, enter the bloodstream as glucose (sugar is half fructose -which is works differently than sugar but more insidiously). Furthermore McKnight says that "surveys suggest that most people don't crave sugar per se. Rather they tend to crave foods high in both fat and sugar, with a majority of the energy coming from fat." Uhh? Sugar is not addictive but only if combined with fat? Ice cream? McKnight's logic fails him here - taste is confused with addiction; fats are not addictive at all; they are needed by the body much more so than sugar; they carry the fat soluble vitamins and minerals and fat soluble phyto-chemicals needed by cells in the body. Sugar does none of this.
Here's the statement that tells me McKnight does not comprehend simple biology - "research suggests that cravings for sugary foods tend to decrease the longer people stay on low-calorie diets." Combine that statement with this one: " Since cravings ought to increase when people abstain from sugar, this provides further evidence that sugar isn't addictive in and of itself." First of all people on low calorie diets are on high carb diets - fruits, grain, and vegetables are all treated by the body (insulin) as a sugar. Glucose by any other name is still glucose; the body does not play semantic games. It is the instability of blood glucose that stimulates the craving - it may not be sugar; it may be pasta, bread, fruit. Want to eliminate the craving? Try low -carb. Blood sugar will stabilize and become normal - craving for sugar (and other carbs) will disappear. McKnight's view, that those who eat in a natural way should not fear becoming addicted to sugar, is correct only if the natural way is the low carb way of eating. Somehow I doubt that that is what he means.