Does eating a lot of sugar give you type 2 diabetes?

Sugary drinks are the clearest culprit. People who drink one to two glasses of soft drinks, energy drinks or fruit drinks per day have a 25 to 26 percent higher chance of developing type 2 diabetes. This is shown by a meta-analysis of eight large population studies involving more than 310,000 participants. Even fruit juice counts: each additional serving per day is associated with a five percent higher risk. The association has been found in multiple independent studies and is statistically robust.

Sugar from solid food works differently. Eating more sugar through regular food is not associated with a higher rate of diabetes. For added sugar consumed through food, no association was found at all. At 20 grams of extra sugar per day through food, the risk was slightly lower. The quality of evidence is low to moderate, but the message is consistent: the form in which sugar is consumed matters. Liquid sugar appears to be more harmful, presumably because drinks make you feel full more slowly and the sugar reaches your bloodstream more quickly.

Early-life exposure may also play a role. Historical research into British sugar rationing after the Second World War shows that people who consumed little sugar during pregnancy and infancy had approximately 35 percent lower odds of developing type 2 diabetes later in life, and developed the disease an average of four years later. It is not a classic randomised study, but the finding points to a possible causal relationship early in life.

Being overweight and getting too little exercise are the most strongly proven, reversible risk factors. In a randomised study with 3,234 participants at elevated risk, a lifestyle programme aimed at seven percent weight loss and 150 minutes of exercise per week reduced the risk by 58 percent. That is stronger than medication: the diabetes drug metformin reduced the risk by 31 percent in the same study.

Besides sugary drinks, processed meats and red meat are the food groups with the strongest evidence for an increased risk. According to one large meta-analysis, people who consume large amounts of these products in combination can even triple their risk. So pay attention to your drinks, processed meats and body weight at the same time if you want to lower your risk.