- Sugar-sweetened beverages raise the risk of type 2 diabetes.
- Drinking sugar is drastically riskier than eating sugar due to its impact on the liver.
- Not all sugars are equally risky, according to BYU study involving half a million people.
Eating your sugar is better for your health than drinking it. Brigham Young University researchers call sugar in beverages a “major culprit” in the growth of type 2 diabetes cases.
Not all sugars are equally risky, according to a new study they conducted that was just published in the journal Advances in Nutrition.
BYU researchers including a pair of students teamed up with researchers at two Germany-based institutions for what’s being called the “largest and most comprehensive meta-analysis of its kind.” Their key finding is that the kind of sugar one consumes and its source are more important than previously thought and not all sugars carry the same degree of risk for diabetes.
Sugar in drinks — think sodas and fruit juice — are “consistently linked” to greater risk of type 2 diabetes, the study found. Other sugar sources showed no such link and, in some cases, might even be associated with reduced risk.
Sugar itself is not inherently harmful, said lead author and nutritional sciences professor Karen Della Corte. The form and amount consumed make the difference.
The study design
The research included analysis of more than 20 cohort studies from different regions of the world, including Europe, the United States, Asia, Australia and Latin America. They involved a half-million people. The researchers adjusted for body mass index, excess energy intake and several lifestyle factors, according to a BYU news release.
The new study found:
- Each additional 12-ounce serving of sugar-sweetened beverages raised the risk of developing type 2 diabetes by 25%. The risk, per the researchers, began with the first daily serving. They found no minimum threshold below which drinking a sugar-sweetened beverage was safe.
- With each added 8-ounce serving of fruit juice each day, risk of developing type 2 diabetes was smaller, but still increased by 5%.
The risks are relative, according to the BYU research team. In the example of someone with a baseline 10% risk of developing type 2 diabetes, for instance, “four sodas a day could raise that to roughly 20%, not 100%.” And individuals have their own baseline risks, depending on personal factors like genetics.
The study found the surprising indication that 20g/day of table sugar and total sugar — which is the sum of all naturally occurring and added sugars in the diet — hinted at a protective relationship.
How could that be?
The researchers suggest that eating sugar and drinking it have different metabolic effects that may account for the difference in risk of developing type 2 diabetes. Sugar-sweetened drinks provide isolated sugars that kick off greater glycemic impact. That can overwhelm the liver’s metabolic process and cause fatty liver and insulin resistance.
Dietary sugars, though, when consumed in or added to nutrient-dense foods like fruit, dairy products and whole grains, don’t overwhelm the liver. “These embedded sugars elicit slower blood glucose responses due to accompanying fiber, fats, proteins and other beneficial nutrients,” per the research.
So sugars eaten with whole foods are much less harmful than those consumed in liquid form, Della Corte said.
She noted that the human body is not accustomed to processing and metabolizing the very high amounts of sugars found in sugar-sweetened beverages. “Sugar has always been a part of the human diet. But in the modern age we’re consuming it differently; we’re consuming it in isolated amounts and not in the context of whole foods.”
Della Corte said sugar is not a “nutritional villain” on its own. What matters is how much you consume and in what form, as well as whether you’re consuming it alongside macronutrients that can slow down its digestion.
“The body can metabolize small amounts of fructose without harm, but when consumed in excess — especially from sugar-sweetened beverages — the liver becomes overwhelmed. Unlike glucose, fructose is primarily metabolized in the liver, where it can be converted into fat through a process called de novo lipogenesis. This buildup of liver fat contributes to the development of non-alcoholic fatty liver disease, which is associated with insulin resistance. Over time, this can increase the risk of developing type 2 diabetes,” Della Corte said.
It’s an unhealthy cycle.
Della Corte said the study was unique in what it examined. Many other studies have looked at the impact of sugary sodas and other beverages, but not whether different types of sugar have different effects. It also examined the impact of sugar on different populations.
Fruit juice not ideal either
Fruit juice is not as good for you as whole fruits. Whole fruits provide fiber, which benefits blood glucose regulation. Fruit juices have too much sugar without the nutritional benefits like fiber that can reduce the risk, Della Corte said.
She said juices have nearly the same level of sugar as sodas have. It’s somewhat less harmful because of the phytonutrients, but not enough to overcome all the potential harms. “It’s a poor substitute for whole fruits,” she said.
She added that high glycemic index foods directly raise the risk of type 2 diabetes, while dietary sugar does not except in liquid form.
“This study underscores the need for even more stringent recommendations for liquid sugars such as those in sugar-sweetened beverages and fruit juice, as they appear to harmfully associate with metabolic health,” said Della Corte. “Rather than condemning all added sugars, future dietary guidelines might consider the differential effects of sugar based on its source and form.”
Type 2 diabetes was the sole health indicator used in the study. And the study didn’t look at the impact of artificial sweeteners, such as those found in diet sodas. Della Corte did note that the people who consume artificial sweeteners often do so because they already have a higher risk of health issues like type 2 diabetes, which could further complicate interpreting a study of the impact of artificial sweeteners.
BYU professors James LeCheminant and Dennis Della Corte, as well as students Tyler Bosler and Cole McClure were also co-authors on the study, along with German researchers Anette E. Buyken of Paderborn University and Lukas Schwingshackl of the University of Freiburg.