Fruit in its whole form is one of the very best things that you can eat. It is high in vitamins, fiber, low glycemic load carbohydrate, and phytochemicals. In the research literature, fruit consumption has been associated with a lower risk of heart disease, stroke, hypertension, and certain types of cancers.
The sugar in fruit in its natural form is surrounded by a helix of fiber. Your digestive system has to break through this fiber in order to digest the sugar. This takes time, so fruit in its whole form has a very easy impact on your blood sugar.
When you juice a fruit, you are separating the sugar from the fiber. What you are left with is pure sugar. This will cause a spike in your blood glucose and insulin levels, which is not a good state for the body. Over the short term, these spikes in blood sugar will leave you hungry a few hours later, so you tend to eat more at the next meal, which can add to weight gain. Blood sugar spikes also can negatively impact your energy and focus. Over the long term, diets with a high glycemic load have been associated with a number of diseases, including heart disease and diabetes.
Juicing a fruit or vegetable takes a seriously healthy food and turns it into the equivalent of a soft drink with a few vitamins. Eat your fruits and vegetables in their whole and natural form and keep your blood sugar on an even keel.