This news story reports that a diet study, conducted on 43 overweight minority children and teenagers, is believed by the researchers who did it to definitively prove that sugar — in and of itself — is metabolically toxic regardless of how much or little of it is eaten, and irrespective of the weight of the eaters. It does a solid job of describing the design of the study and discussing why the evidence it provides is qualitatively different from previous research. But we thought the framing of the story was off kilter, as it leads with lots of glowing discussion about the strength and importance of the research, while putting important caveats and limitations far down in the piece. We also think the story could have been more thorough in its discussion of those limitations — including the fact that 43 is a small number of participants, the study was very short in duration, and it had no control group. But while there was room for improvement, readers who make it to the end of the piece should come away with a reasonably thorough understanding of the study’s findings and what they might mean.
It’s hard to imagine that any American family could be completely uninformed about the health-related risks of consuming high fructose corn syrup and table sugar (sucrose), major components of sweet drinks, and a supermarket full of processed foods. But as the article points out, it has been difficult to design studies that show that such “added sugar” is an independent toxic substance even when total calories and weight stay the same. That difficulty, in turn, has made it hard to say with certainty whether people who reduced their sugar consumption and were improving their metabolic health (e.g. blood pressure, liver function, cholesterol levels, fat accumulation in the abdominal region) were getting the benefit from less sugar or from fewer overall calories. Given the growing rates of diabetes, fatty liver disease and heart disease in ever-younger populations, adding to evidence that not all calories are equal in harm or benefit is more than welcome by physicians and parents. And studies like this one to add to a growing body of evidence that restricting sugar may be good public health policy. If additional studies, longer in duration and larger in scope are done, this could result in policy change that may help keep everyone healthier.
Many sugar-rich packaged and prepared foods are more expensive than home-made foods.But the study was not designed to compare the costs of diets, and most people know how much different types of food that contain sugar cost. So we’ll rate this Not Applicable. On the other hand, it would have been useful to cite estimates of the cost of treating the disorders linked to metabolic syndrome components, such as high blood pressure, as well as the costs of treating the chronic diseases that are a consequence of the syndrome, such as diabetes and heart disease.
The quantification of the results does not quite clear our bar here. The story says this:
Overall, their fasting blood sugar levels dropped by 53%, along with the amount of insulin their bodies produced since insulin is normally needed to break down carbohydrates and sugars. Their triglyceride and LDL levels also declined and, most importantly, they showed less fat in their liver.
We would have preferred more numbers documenting the changes for each outcome, in absolute terms (the “53%” figure is a relative reduction), along with a comment or some description of how meaningful the changes were clinically.
It’s hard to say what “harms” or risks would result from cutting sugar from childrens’ diets. We’ll rate this Not Applicable.
The story does a fine job of explaining how the study was done and why the evidence it provides is meaningful. It explains that compared with previous research, which was observational in nature and couldn’t prove cause and effect, the new study suggests that cutting out sugar may be causing the beneficial metabolic changes observed. We do have a problem with the story’s framing, however, which frontloads discussion about how important the findings are, while burying discussion of limitations far down in the text. Experts point out some problems with the study, but we think the story could have gone further — explaining for example that the study was small and time-limited and that it had no control group. Though the story feels slightly unbalanced, we’ll acknowledge that it did make an attempt to critically evaluate the findings — hence the Satisfactory rating.
As noted, increased sugar consumption, especially in children, has long been linked to alarmingly high and growing rates of obesity, diabetes and other chronic diseases in children and adults. There is no disease mongering here, and indeed, some numbers (prevalence) would have helped the story.
The story includes restraining comments from two independent experts, although those comments come far down in the story and should have been placed higher. The story perhaps also could have mentioned that Dr. Lustig is author of a 2012 book called “Fat chance: Beating the Odds Against Sugar, Processed Food, Obesity, and Disease,” and so may have an intellectual and financial conflict of interest when it comes to sugar. The study was funded by the NIH and Touro University, as well as UCSF — another aspect that could have been mentioned for context.
The article did a fairly good job of describing the limitations of previous dietary studies, compared to this one, especially as it relates to the effects of cutting sugar vs. losing weight. It would have also been helpful to mention the role of exercise in controlling metabolic disease.
The story explains that the dietary changes they made in the study could be made by anyone. The story says:
“We took chicken teriyaki out, and put turkey hot dogs in. We took sweetened yogurt out, and put baked potato chips in. We took pastries out and put bagels in,” says Lustig. “So there was no change in [the children’s] weight and no change in calories.”
It’s always risky at best to call something a first of its kind as this story does, without citing any evidence for that or being more specific about what, exactly, was a “first.” But the story does give the general sense of what’s new and important about the study — the fact that it suggests beneficial changes of reducing sugar independent of weight loss. And it also draws a line between previous correlation studies and this experiment. Close call here but we’ll give the benefit of the doubt.
There’s enough original reporting here for us to be sure this story didn’t rely on a news release.