Systematic Review Reveals Why That Morning Glass of Fruit Juice May Do More Harm Than Good

A new study led by Brigham Young University (BYU) in collaboration with German research institutions has found that regular consumption of fruit juice may increase the risk of type 2 diabetes. Published in the journal JAMA Network Open, the large-scale meta-analysis concluded that each additional 230ml serving of fruit juice per day is associated with a 5% increased risk of developing type 2 diabetes. In contrast, natural sugars consumed through whole foods like fruits and dairy do not carry the same risk and may even be linked to a reduced risk of the disease.

The study analyzed data from more than 500,000 individuals across multiple countries to explore how different forms of sugar impact metabolic health. Researchers compared the effects of sugars consumed in beverages-both natural and added-to those found in whole foods. They discovered that sugar-sweetened beverages like soda had the highest impact, raising diabetes risk by 25% per 350ml serving. Fruit juice, often perceived as a healthier alternative, also contributed to an elevated risk, though to a lesser extent.

“When sugar is consumed through drinks, it rushes into the bloodstream quickly, triggering a spike in blood glucose,” the researchers explained. “This sudden overload can overwork the liver and disrupt insulin sensitivity, both red flags for type 2 diabetes.”

The key difference lies in how sugar is delivered to the body. Whole fruits come with fibre, vitamins, and antioxidants, which slow digestion and stabilize blood glucose levels. Juices, stripped of fibre, deliver concentrated sugar in liquid form, causing rapid glucose spikes. While fruit juice retains some nutrients, the absence of fibre and the high sugar concentration diminish its health benefits.

This research marks a significant shift in nutritional thinking. While fruit juice may still have a place in the diet, moderation is essential, and whole fruits remain the better choice for metabolic health.

Reference: Della Corte, K. A., Bosler, T., McClure, C., Buyken, A. E., LeCheminant, J. D., Schwingshackl, L., & Della Corte, D. (2025). Dietary Sugar Intake and Incident Type 2 Diabetes Risk: A Systematic Review and Dose-Response Meta-Analysis of Prospective Cohort Studies. Advances in Nutrition, 100413.