Smoothies are often seen as a quick and nutritious way to fuel your body, but not all ingredients are safe when it comes to blood sugar and weight management. While many of these add-ins can be packed with vitamins and fiber, certain smoothie additions may lead to unexpected blood sugar spikes and fat storage.
We consulted health experts to identify four seemingly “healthy” smoothie ingredients that may contribute to blood sugar spikes and weight gain. According to their insights, whole milk, canned fruit, coconut oil, and peanut butter are the ingredients to be mindful of. Keep reading to learn why.
1. Whole milk
If you prefer a creamy, rich smoothie, you're likely to add some type of dairy like milk into the blender. However, Jay Cowin, registered nutritionist and Director of Formulations at ASYSTEM, and Trista Best, registered dietitian at Balance One Supplements, warn against certain creamy ingredients like whole milk.
According to Cowin, some dairy options are "high in saturated fat and calories, which can sabotage your weight loss efforts." He suggests choosing "low-fat or non-fat dairy products like skim milk or Greek yogurt," which offers a ton of protein and other health benefits.
But if you think going plant-based is a good option, Best suggests otherwise, noting that many dairy alternatives are "still high in calories, fat, and sugar," so it's always a good idea to keep an eye on the nutrition label.
2. Canned fruit
Fruit is an important part of any delicious smoothie recipe. However, choosing the right kind of fruit matters if you want to stay healthy. Certified nutritionist Khushali Shah warns that you should avoid canned fruits as much as possible if you want to manage your blood sugar and keep your body happy and healthy. They're convenient, but they have some downsides when it comes to blood sugar levels.
"Canned fruits are often packed in syrup, which can add a lot of unnecessary sugar and calories to your smoothie," Shah says. "Some canned fruits are packed in water or juice, but they still contain added sugars or preservatives. Both of these can cause a spike in the blood sugar levels."
In addition to all that sugar, there are a few other reasons fresh fruit trumps canned fruit: "Canning fruits sometimes result in them losing some of their vitamins and minerals, and may also contain added sodium." Shah says. The same is true for most canned foods out there.
3. Coconut Oil
Coconut oil is an edible oil that is derived from the "meat" and milk of the coconut palm fruit. While coconut oil can be extremely beneficial for taming frizzy hair and moisturizing dry, flaky skin, Amber Dixon, a registered dietitian, and CEO of Elderly Assist Inc. warns against adding it to your smoothie not only because they are high in empty calories, but also because of the concerning saturated fat and MCT levels. She explains, "Coconut oil is high in saturated fat, which is not good for your blood sugar levels, so it can cause you to store more fat than you need—and that's bad news for your waistline! It also contains medium-chain triglycerides (MCTs), which aren't exactly healthy either." MCTs are a type of fat found in your blood. If they're consumed in high quantities, they can negatively affect your cholesterol levels—both the total cholesterol and LDL (or "bad") cholesterol levels, both of which are risk factors of heart disease. They may also stimulate the release of hunger hormones, making you overeat.
Instead, she recommends using avocado oil in your smoothies. "Coconut oil can be a great way to add healthy fats and flavor to your smoothie, but it's pretty heavy. Avocado is a fantastic alternative because it's almost as creamy and bubbly as coconut oil, but it's also got an amazing taste of its own. It's also a very versatile ingredient—you can use it in anything from hummus to salad dressing!" Dixon raves. Yum!
4. Peanut Butter
Another popular smoothie ingredient that is also surprisingly unhealthy according to Dixon is peanut butter. Even though peanut butter adds a sweet flavor and a rich, creamy texture, it's also high in calories and fats. While the healthy fats in this nut butter are nutritious and beneficial for weight loss, you should really only be consuming them in moderation to avoid fat buildup. "Peanut butter has protein and fiber," Dixon warns, "but it's also very high in calories—and since smoothies are generally low-calorie drinks, you don't want to go overboard on the peanut butter to keep your calories down while still getting enough nutrients." And, commercial peanut butter from brands like Jif and Skippy is loaded with added sugars, oils, and fats that give the nut butter a syrupy taste and smooth texture.
But, what can you add to your smoothies to get the protein and fiber your body needs to shed pounds? Dixon suggests swapping out your peanut butter for some nuts or seeds, "like raw almonds or chia seeds." Not only are they chock full of protein and fiber, but they are also antioxidant-rich and can be metabolism-boosting to encourage weight loss. Adding raw seeds and nuts to your smoothie is a win-win!
