Consuming fructose-sweetened beverages at 25% of daily energy needs for 10 weeks increases hepatic de novo lipogenesis, visceral adiposity, postprandial triglycerides, small dense LDL cholesterol, and insulin resistance in overweight or obese adults compared to glucose-sweetened beverages, despite equivalent weight gain.

When fructose is consumed, the liver processes it differently than glucose, producing more fat from scratch. This excess fat builds up in the liver and gets packaged into blood fats that circulate longer because the body can't break them down efficiently. These lingering fats settle in the belly, make blood cholesterol smaller and denser, and block the liver's ability to respond to insulin, raising blood sugar.