Smoothie Ingredients You Should Avoid At All Costs, According To Our Expert

Smoothies can be thirst-quenching, palate-pleasing, high-nutrient meal replacements and snacks. Additionally, they may help you keep trim, as shown by a 2024 study published in the American Journal of Health Promotion. The study found that regular consumers of fruit and veggie smoothies gained less weight than consumers who didn't drink smoothies routinely. But stay watchful because even healthy-seeming smoothies aren't always healthy. Many smoothie recipes are filled with ingredients that are best eaten in moderation, especially if you're trying to limit your intake of calories, sugars, carbohydrates, or fat.

What ingredients are best left out of your homemade and store-purchased smoothie concoctions? According to Jamie Koll, a health coach and the founder of GIRLS WHO EAT, five popular add-in foods have the potential to bring down the nutritional value of smoothies. They include fruit juice, canned fruit, protein powders, flavored syrups, and ice cream.

Although some of those ingredients may sound like they're good for you, such as fruit juice, each of them can potentially sabotage your weight management and fitness regimen. And that's the last thing you want if you're like Koll and want to make clean eating a daily habit. However, you can make smarter swaps for each of the five foods without giving up taste, texture, or consistency.

Are you someone who likes to add at least a splash of fruit flavor to your smoothies? Fruit can improve the sweetness of a smoothie and take away the bitterness of popular greens. Yet both fruit juice and canned fruit aren't perfect substitutes for the real thing.

What's wrong with thinning out a smoothie with fruit juice? As Koll explains, fruit juices lack the fruits' fiber. Plus, if they're made from concentrate, they've been processed to remove most of the water content. The result is a sugary juice that can cause blood sugar levels to spike.

Canned fruit is similarly concerning from a nutrition standpoint. In Koll's experience, canned fruit "can add a lot of unnecessary sugar to your smoothie" because the fruit's frequently surrounded by a refined sugar syrup. Again, all that sugar could throw your blood sugar off-kilter. Or, it could simply raise the calorie content of your smoothie.

That's not all. The canning process may alter the nutrients in your fruit as well. A 2021 study in Foods evaluated the nutritional effect of canning on mangoes and pineapple. Researchers found that mangoes and pineapples that had undergone thermal-based canning were less nutritionally rich in healthy phytochemicals than their fresh counterparts.

Another study in a 2022 edition of Frontiers in Nutrition explored the nutritional breakdown of antioxidants in canned apricots. The research team concluded that, after 12 months, the antioxidants in the canned whole and halved apricots had been noticeably reduced.

What about protein powder? Though it's trendy to toss a scoopful of protein powder into smoothies, Koll notes that protein powders can rely on high-fructose corn syrup or multiple refined sugars to improve their palatability. 

Even if you purchase a protein powder that's free from added sugars, be on the lookout for ingredients like sucralose and acesulfame potassium (Ace-K). They're artificial sweeteners that Koll says can affect the balance of the gut microbiome. When the gut microbiome is disrupted, it can't work effectively and may leave you with belly problems like bloating, indigestion, lessened nutrient absorption, or inflammation. According to the Cleveland Clinic, this condition is called dysbiosis and can increase the risk of developing medical problems like fatty liver disease, irritible bowel syndrome, difficulties absorbing nutrients, mood problems, and chronic fatigue syndrome.

Flavored syrups can wreak havoc on your gut biome balance, too. Like protein powders, many are made with artificial sweeteners. They may also contain food dyes, which have been associated with allergic reactions. Though a 2022 investigation of food additives in Allergo Journal International stated that serious allergic responses, including anaphylaxis, are rare, the authors cautioned against underestimating the importance of hypersensitivity to add-ins like food coloring. Therefore, it's best to just say no to such flavorings.

It may go without saying that putting ice cream in your smoothie turns it into more of a milkshake than anything else. Ice cream, explains Koll, "is often full of high amounts of sugar and can contain artificial flavors, dyes, and preservatives that are not healthy." In other words, if you're craving ice cream, just eat it in small portions as a once-in-a-while treat — and resist the desire to plop some into your blender for your morning or after-gym smoothie fix. Alternatively, you might want to consider dishing plain Greek yogurt into your smoothie to give it a creamy consistency without loading up on unwanted calories, fat, or sugars. 

Per data from the U.S. Department of Agriculture, a 100-gram serving (a little more than half a cup) of low-fat Greek yogurt offers 73 calories, 1.92 grams of fat, and 3.56 grams of sugar. By comparison, a Healthline table shows that a half-cup of low-fat vanilla ice cream brings along 130 calories, 2.5 grams of fat, and 13 grams of sugar. Consequently, Greek yogurt may be a better smoothie inclusion to help you achieve your healthy lifestyle goals.