Is it OK to use juice in a smoothie?

Use milk or water instead. A cup of orange juice adds 21 g of sugar and half a gram of fiber, and nothing else your glass needs. The 2025 to 2030 US guidelines say juice should be “consumed in limited portions or diluted with water,” and the whole fruit is already in the blender.

Juice feels like the natural liquid for a fruit smoothie, and it’s how plenty of recipes start one. It’s also the one ingredient that turns a glass of whole fruit back into something closer to a soft drink, because it’s fruit with the part that fills you up taken out.

Orange juice is an orange with the chewing taken out. You’d stop after one or two oranges, but a glass of juice is gone in a minute.

Juice and honey

C

The juice bar glass C

4 g protein, 17 g added sugar

or

Milk and yogurt

A

Strawberry banana yogurt A

30 g protein, no added sugar

What does a cup of juice add?

Juice and milk cost about the same calories. The difference is what comes with them, and milk brings protein where juice brings more sugar. Orange juice does have a lot of vitamin C, 124 mg a cup, but a cup of frozen strawberries in the same glass covers most of a day’s vitamin C on its own.

Does juice count as added sugar?

Plain 100% juice doesn’t, under the guidelines’ definition. Juice concentrate does, since “fruit juice concentrate” is on the guidelines’ list of added sugars, next to honey and turbinado. That makes a difference at the chains. Smoothie King’s Caribbean Way lists a papaya juice blend and turbinado, and Jamba’s Strawberry Whirl lists a pear and apple juice concentrate blend. Jamba’s nutrition sheet (October 2026) gives total sugar only, 56 g in a medium, so you can’t tell how much of it was added.

In our grade, juice counts as fast carbs on the Glucose meter, the same as added sugar, since it’s sugar you drink with almost none of the fiber that slows it down. Whole fruit counts as slow carbs even blended, which is why the guidelines ask for fruit “in their original form.”

Why does juice fill you up less?

Nothing gets chewed, and only a fraction of the fruit’s fiber is left. In a 2009 study, 58 adults had about 125 calories of apple before lunch, as a whole apple, applesauce or juice. With the whole apple they ate 187 fewer calories in all. With the juice they ate 9 fewer, about the same as eating nothing first. Putting the apple’s fiber back into the juice barely helped. Why am I hungry after a smoothie? has the full story.

What should I use instead?

• Milk for a meal: 8 g of protein a cup, and the creamiest result.
• Unsweetened soy milk if you’re dairy-free: 7 g of protein for 80 calories.
• Water and ice for a lighter glass, with Greek yogurt doing the protein.
• A little coconut water if you like the taste, though check the label for added sugar.

The builder shows the swap’s effect on your own glass, and the quiz’s first fix is often exactly this one.