Fruit juice might sound healthy—after all, fruit is part of a well-rounded healthy diet—but take a quick glance at the nutrition label and you'll see that juices and juice blends are mostly just pumping your body full of sugar and vitamin C.
So what changed? How does fruit go from diet friend to diet foe when it comes in the form of a drink? The answer is fiber. Missing from juice, fiber is found in whole fruits and can help slow down digestion, keep you full longer, and keep your gut healthy. The combination of natural sugars from the fruit juice and potentially added sugars from artificial sweeteners, plus the elimination of dietary fiber makes for a high sugar-to-fat or sugar-to-protein ratio, leaving limited resources available to slow down an inevitable sugar spike.
A recent study published in the British journal BMJ Open found that a 200ml (6.5-oz) portion of some 100 percent fruit juices, juice drinks, and smoothies contained more sugar than the daily recommended amount for a child. One teaspoon of table sugar is equivalent to 4 grams of sugar you see on the nutrition facts label, which means an 8-ounce glass of 100 percent cranberry juice could contain as much as 7 teaspoons of sugar—and some juice blends may contain even more. At roughly 110 to 120 calories per glass, this translates to 5 percent of your total calorie intake for the day for someone consuming 2,000 total calories a day. Calories are calories even if they come from juice, and sugar is sugar even if it comes from fruit.
According to the 2015–2020 Dietary Guidelines for Americans, no more than 10 percent of your daily calories should come from added sugars, which are commonly found in juice drinks, energy drinks, and desserts. This does not include natural sugars found in grains, fruit, or dairy products, but rather the sweeteners such as honey, molasses, and corn syrup that are ubiquitous in many foods today. Although most the sugar in fruit juice is derived from fruit, and thus not technically "added sugar," it is still processed in your body as any other sugar and should be monitored as part of overall daily added sugar and caloric intake. Bottom line? If you're craving something sweet, go for the whole fruit instead.