If there is an excess of fructose that can’t be stored as glycogen, the liver converts that into fat and stores it there as such. Consistently consuming a lot of fructose can contribute to the development of nonalcoholic fatty liver disease over time.
Juice is not filling
In addition, fructose has an effect on satiety—and not in a good way: studies indicate that after consuming fructose, neither of the hormones that indicate to the brain that the stomach is full—insulin and leptin—increase significantly. This is a problem because these hormones also regulate energy intake. Therefore, fructose has the potential to massively disrupt your metabolism. It can happen pretty quickly when you consume more fructose than your body actually needs in terms of calories.
In addition, large amounts of fructose pose a challenge for the intestines because fructose is difficult to digest; it’s particularly hard for the body if your naturally sweet fruit juice also contains added sugar.
Juice increases the risk of diabetes
A study in The British Medical Journal found that increased juice consumption can increase the risk of diabetes. And, the study shows that it makes a big difference whether fruit is eaten whole or pressed into juice.
For the study, the eating habits of almost 190,000 people were evaluated. Two servings of whole fruit per week were proven to reduce the risk of developing type 2 diabetes by 23 percent.
But the risk of developing type 2 diabetes increased by 21 percent for participants who consumed one or more servings of fruit juice per day. One reason for this lies in the processing of the juice: you get the nutrients, but secondary plant substances and fiber are lost. When making fruit juices, the fiber is often removed or destroyed—but it is precisely this fiber that helps to stabilize blood sugar levels and increase the feeling of satiety.
Is juice healthy?
Overall, it’s truly best to enjoy fruit juice (and other juices containing a lot of fruit) in moderation. As boring as it may seem, you really should stick to water and unsweetened herbal teas when thirst arises.
But for those moments when you really want to consume undiluted juice—life is short, juice is delicious, and we’re only human, after all!—there are some things to keep in mind. Stick to freshly squeezed versions if possible, even if they are more expensive than pre-packaged versions. These tend to contain more nutrients because the juice is drunk immediately after pressing, and the nutrients won’t have been destroyed by long storage or heat. Or, try it in the form of a spritz: three parts fizzy water and one part juice.