Are Smoothies Always a Healthy Choice?

March 27, 2026

Close up of hands holding a blender containing fruits and milk for a healthy fruit smoothie

Smoothies can be an easy way to pack fruits, protein and other nutritious ingredients into your day, but not all smoothies are actually healthy. “It really depends on what’s in your smoothie,” says Kathryn Hummer, RD, LD, a clinical dietitian in the bariatric surgery program at University Hospitals. “A lot of people think all smoothies are healthy because they're a good source of fruit and maybe some vegetables, but they often contain more sugar than people realize.”

When Smoothies Become Dessert

Whether you’re making your own smoothie, picking up a ready-to-drink smoothie at the store or ordering a fresh one at a smoothie shop, it’s important to pay attention to the ingredients and nutrition facts, especially sugars.

Hummer says that a common problem with smoothies is that they often contain too much fruit. “People don’t always pay attention to the amount of fruit in the smoothie, and they could end up with three or four servings, which adds too much sugar.”

The kind of liquid you use in a smoothie also makes a difference. “Juice, especially orange juice, is a popular choice to make smoothies less thick, but that's another source of sugar,” says Hummer. “A half of a cup of orange juice is going to give you 15 grams of sugar, so it adds up really quickly.”

Certain milks, like cow’s milk, plant milks and flavored milks (like vanilla or chocolate) can also be hidden sources of sugar, so again, it’s important to check labels and pay attention to ingredients. If you’re buying a smoothie at a shop, Hummer says it’s a good idea to check the nutrition facts on the shop’s website before you order to make sure you’re getting a nutritious and well-balanced smoothie.

How to Build a Better Smoothie

Balancing the different food groups is key. Smoothies should include more than just fruit, milk and ice. “Add vegetables, healthy fats and think of other options besides just milk for protein, especially if you’re using the smoothie as a meal replacement,” says Hummer.

Ideally, a smoothie should contain ingredients from three main food groups:

A protein
A carbohydrate or high-fiber food
A healthy fat

“This balance will make your smoothie more of a meal replacement, rather than a dessert,” she says.

Protein

Protein is an important ingredient because it's digested slower and helps keep you feeling full for longer. It also helps slow down the release of sugar into your blood when you're eating a meal. “You definitely want to have a good source of protein,” says Hummer. “Cow and soy milk typically provide about 8 grams of protein per one-cup serving.”

Eight grams is less than the recommended amount of protein you should have at a meal, so Hummer suggests boosting the protein for a meal replacement smoothie. “You could add half a cup (5 ounces) of nonfat or low-fat plain Greek yogurt or no-sugar-added vanilla-flavored yogurt,” she says. If you’re using the smoothie to replace a meal, aim for 15 to 20 grams of protein.

Another option is to add a protein powder, like whey protein, which tends to be easy to digest. “Protein powders can be a fun way to flavor your smoothie, too,” she says. “I’ve seen flavors like ‘chocolate brownie’ or ‘strawberry shortcake.’” You can also use a ready-to-drink protein beverage, but Hummer points out that protein powders are usually more budget-friendly.

High-Fiber Foods (Carbs)

“A good source of fiber in a smoothie would be anything that's higher than 4 grams per serving,” says Hummer. When choosing your fruits, she suggests limiting them to just two servings. To help guide you, she shares examples of one-serving sizes of fruit (that’s about 15 grams of carbohydrates per serving):

1 cup of whole strawberries
1 small apple (about the size of a fist)
3/4 cup of pineapple
1/2 cup of sliced mango
1/2 of a banana (a whole banana would be 2 servings)

“You can also add vegetables,” she says. “I've had patients tell me that they like to put in celery, romaine lettuce and spinach.” Adding a cup or two of spinach is especially popular because it doesn’t add an overpowering flavor and the soft leaves tend to blend well in the smoothie. Kale is another popular option. “Veggies can be a good way to add more nutrients,” she says. “They’re not going to contribute a ton of fiber, but they can add volume and make it a little more filling.”

Healthy Fats

Fats can also be part of a healthy smoothie, particularly if the smoothie is meant to replace a meal. “It just comes down to portion control,” says Hummer.

Examples of healthy fats include:

1 tablespoon of peanut, almond or cashew butter
1 tablespoon of chia seeds
2 tablespoons of brown flaxseed
1/4 of an avocado

“These are great options for adding healthy Omega-3 fatty acids, and also some really great fiber,” says Hummer. “Fats are also going to break down slower in the body, so they’ll help you feel fuller longer.” Try to get about 5 grams of healthy fat.

Avoid or Limit Sugar

Hummer recommends avoiding adding any extra sugar, including honey or agave syrup. If you want to add more natural sweetness, she suggests using very ripe bananas or pears. “They can add a lot of great sweetness and flavor when they're super ripe,” she says. Another good option, especially if you have diabetes, is liquid Stevia drops. “If you’re buying a smoothie, make sure the sugar is less than 5% of the recommended daily value,” she says.

Pay Attention to Portion Size

After blending, your smoothie serving should be about 8 to 11 ounces, depending on the amount of liquid you put in it. “This is going to come down to personal preference,” says Hummer. “Some people like their smoothies super thick, so it might be closer to a cup (8 ounces), and some like them a little bit thinner, so the serving size could be closer to 10 or 11 ounces.”

If you’re buying a prepared smoothie, check the serving size on the label to make sure you’re consuming the right amount. Depending on your nutrition needs, you can also check the label to find the amount of calories per serving, the number of grams of fat, the grams of carbohydrates, as well as if there are any added sugars that you’ll want to avoid.