In addition to being a great way to pack in the protein and nutrients you'll need to fuel your day, fruit-filled smoothies look awesome on your Instagram feed—hey, just being honest. (These drinks are more than just a grab-and-go breakfast. Try these Smoothie Recipes for the Perfect Meal of Snack.) Now, a new study is offering yet another reason to get sipping, and it's all in one simple trick that turns an already healthy smoothie into a cravings crusher: make it thick.
A small study, published in the American Journal of Clinical Nutrition, found that simply making your morning smoothie thicker can help keep you on track with your health goals. Researchers had 15 men drink four different smoothies which varied in both calorie content (either 100 calories or 500 calories) and thickness (categorized as thin or thick).
After downing each drink, researchers scanned the participants' stomachs using an MRI to determine how physically full they were and how full they stayed. The guys were also asked to rate their appetite on a 100-point scale. Both markers were recorded every 10 minutes for up to an hour and a half after
Unsurprisingly, the thin 500-calorie smoothie kept people fuller longer than the 100-calorie thin version—more calories mean more energy to burn through. More interesting, the smoothies' thickness mattered more than the calorie content. People who drank the thick 100-calorie smoothie reported feeling fuller for even longer than when those who drank the thin 500-calorie smoothie. (Looking for smoothie satisfaction but can't do dairy? No worries, these High-Protein Vegan Smoothies are just for you.)
The reason, according to the study authors, seems almost too simple: The thicker the drink, the more it fills up your stomach and the longer you'll avoid feeling hungry again. They call this "phantom fullness." It's reasonable to assume this could also have to do with the fiber content in the thick smoothies. We already know that juicing fruit and veggies strips away all that filling fiber and leaves you with basically sugar, creating a quicker crash, so the same effect could be happening when you blend your smoothie ingredient to smithereens. "Keep in mind that juicing does strip produce of dietary fiber, which is found in the pulp and skin of produce and aids in digestion, regulates blood sugar levels, and keeps you feeling full longer," says registered dietitian Keri Glassman. "So whole foods are still the optimal way to ensure you're getting plenty of fiber in your diet."
But before you go adding a double dose of froyo (hey, that's thick, right?) make sure you choose your thickener wisely. To get an added nutritional boost of healthy fats and protein, reach for avocado, peanut butter, and plain Greek yogurt, says Keri Gans, R.D.N, author of The Small Change Diet.