For many decades, folk “wisdom” claimed that diabetes was caused by eating too much sugar.
There have always been curious ideas in the diabetic world. For instance, people with advanced diabetes excrete a lot of sugar in their urine, so one early diabetic diet prescribed eating nothing but candy, on the theory that because the patients were losing so much sugar in their urine, they should replace it with sugar in their diet.
Shortly after I was diagnosed, I had an idea of why people might think that eating sugar caused diabetes. For about 6 months previously, I had craved sugar. I think it was because my cells had trouble taking up sugar, so they made me want to eat more sugar. But in fact, I think it was the diabetes that made me want more sugar rather than eating more sugar that gave me diabetes.
If this were true, it’s unlikely that friends and relatives would analyze the situation. They’d see someone eating a lot of sugar and then getting diabetes and they’d assume that the sugar had caused the diabetes.
One day the former owner of my house dropped in to visit and offered me a big bag of peaches. I explained that I wasn’t eating a lot of fruit because I had diabetes, and she said, “But you didn’t eat a lot of sugar.” An odd comment as she had no idea what I ate, but it confirmed that many people think that sugar causes diabetes.
Studies done in the 1980s in animals and humans showed that sugar had no effect on obesity, metabolism, or the development of diabetes in genetically prone individuals, according to one author of many of these studies, Richard S. Surwit. He said that it was only sugar in combination with fat that caused problems.
But now a new study suggests that sugar (either sucrose, “table sugar” or high-fructose corn syrup (HFCS), which has approximately the same composition) may be one cause of diabetes. Sucrose is half glucose and half fructose; HFCS has approximately the same composition. The “high” refers to comparison with regular corn syrup, which is almost all glucose. The full text of the study is also available online.
This is not a perfect study; it is not a randomized, double-blinded study in which you assign people at random to one of two treatment options and then follow them to see how they do. It wouldn’t be ethical to tell thousands of people to eat a lot of sugar for 10 years or so to see if they developed more diabetes.
Instead, the researchers analyzed available data on the availability of sugar in 175 different countries and then used statistics to see if the availability of sugar was related to any health outcomes, including obesity and diabetes. Of course, availability is not the same thing as consumption, so the researchers had to estimate how much waste occurs in various countries. They said people in the United States waste more food than those in other countries.