Doctors used to think sugars were terrible for diabetes. Then the American Diabetes Association (ADA) changed their minds. They said it’s the carbs that matter, and sugars were just another carb. Now some scientists are saying sugar is poison. Who’s right?
In 2006, Amy Campbell laid out the official ADA position here, in a piece subtitled “fitting sugar into your meal plans.” “We now know,” she wrote, “that for the most part, it’s the total amount of carbohydrate, not the type of carbohydrate that you eat, that affects blood glucose levels. This means that the same amount of carbohydrate from any carbohydrate-containing food affects blood glucose levels in pretty much the same way.”
ADA’s own Web site says something similar: “The total amount of carbohydrate you eat affects blood glucose levels more than the type. Now experts agree that you can substitute small amounts of sugar for other carbohydrate-containing foods into your meal plan and still keep your blood glucose levels on track.”
They give the example of taking a slice of bread off your turkey sandwich to make room for some cookies. ADA does caution that “drinking sugary drinks is linked to Type 2 diabetes, and the ADA recommends that people limit their intake of sugar-sweetened beverages to help prevent diabetes.”
Is sugar really just another carb? Some experts say no way. Quinn Phillips wrote here in 2011 about how researchers like Dr. Robert Lustig, an obesity expert at the University of California, San Francisco, School of Medicine, are saying sugars, especially fructose, have toxic effects in the kidneys and liver. Lustig believes our high sugar intake is responsible for the recent increases we have seen in the prevalence of the metabolic syndrome (the coexistence of insulin resistance, hypertension, obesity, and abnormal blood lipid levels).
Let’s see how much of this we can sort out. It’s true that all sugars are carbohydrates, and all carbs except fiber break down into glucose in your blood. But they do this at different rates and in different ways. To say sugars are just another carb ignores the glycemic index (GI) of foods. Carbs with a high GI raise blood glucose levels faster than low-GI foods, so put more of a strain on the pancreas and are perhaps more likely to increase insulin resistance.
Most sugars are very high-GI foods. But some starches, like white breads, break down so quickly that they put glucose into the system as fast as or even faster than most sugars!
So why would sugars be worse? If you take the right amount of insulin, timed precisely to cover the glucose from sugar or starch, everything should go smoothly. Right? Well, maybe a well-controlled Type 1 with no insulin resistance could do that, although it’s difficult to get the numbers exactly right. But a person with insulin resistance, like all people with Type 2 and many people with other types of diabetes, will still suffer from the rapid sugar dose. Their cells may say, “Oh, no, here comes another load of glucose and I’m not ready for it,” and they may become more insulin resistant.
Also, while sugars make your glucose climb rapidly, they also tend to make them drop fast on the other side. So an hour later you might be hungry again, and tend to crave more sweets.
Third, there seems to be good evidence that sugars and other high-GI foods can be addictive. In a recent article in Psychology Today, Alexis Conason, PsyD, wrote that “[MRI scans show that] sugar activates the same brain regions that are activated when a person consumes drugs like cocaine.” She also quotes Eric Stice, PhD, a neuroscientist at the Oregon Research Institute, who found that “heavy users of sugar develop tolerance” (needing more and more to feel the same effect), which is a symptom of substance dependence.
Lastly, sugars don’t have much nutritional value besides the energy rush. So they’re good for a boost when you need to be physical, but don’t do much for you in the long run.
So there are at least three problems with the theory that “sugar is just another food.” It can increase insulin resistance, lead to low blood glucose after the initial rush, and can addict you so that you can’t “eat just one.”
Not all sugars are the same. There are many different naturally occurring sugars, and we now have a number of manufactured ones. Most prominent is high-fructose corn syrup, or HFCS. HFCS is Dr. Lustig’s enemy number one, and other scientists agree.
Just as I was writing this piece, a new study came to my inbox reporting that “countries that use HFCS in their food supply had a 20% higher prevalence of diabetes than countries that did not use HFCS.” Run by scientists at Oxford University and the University of Southern California, the analysis also revealed that HFCS’s association with the “‘significantly increased prevalence of diabetes’ occurred independent of total sugar intake and obesity levels.”
The article, “High Fructose Corn Syrup and Diabetes Prevalence: A Global Perspective,” appeared in the journal Global Public Health online.
I personally think sugars and refined flours should be avoided as completely as possible. They’re just not good for us. But what do you think?