Here’s the secret to whipping up a satisfying smoothie that will taste delicious and keep your blood sugar in check, from an endocrinologist. According to board-certified endocrinologist Brittany Henderson, M.D., to avoid that blood sugar crash, you’ll want to lean into high-fiber, low-glycemic index fruits like berries and apples. “I also recommend adding insoluble fiber like psyllium husk or prebiotic fibers to help reduce the blood sugar spike, or flax/chia seeds,” she tells mbg. Here are some more high-fiber foods and fiber supplements to play around with in your smoothie. And as registered dietitian Jessica Cording, M.S., R.D., CDN, previously wrote for mbg, you’ll also want to “make sure to keep portions in check on the fruit and work in some healthy fat and protein.” She recommends aiming for about 2 parts veggies for every 1 part fruit—and has a go-to smoothie recipe that hits all these marks. What you’ll need: