It's no secret why smoothies have become staples in many health-conscious diets: They're convenient, customizable and a great way to eat more fruits and veggies. And if you want to start your day with a drinkable meal, you're better off going with a homemade smoothie than a pre-packaged shake -- those can come loaded with sugar, according to Harvard Medical School. Even homemade smoothies can be high in calories, though. Stick to lower-cal ingredients for a calorie-conscious smoothie that's still filling and delicious.
Start With Your Smoothie Base
The liquid you use to make your smoothies affects their nutritional value. Avoid fatty fluids -- like full-fat milk -- or sugary options like sweetened soy or almond milks. Instead, use nonfat milk, which contains 91 calories per 1-cup serving; unsweetened soy milk, which has 80 calories per serving; unsweetened almond milk at 39 calories per serving; or coconut milk beverage, which has 71 calories per serving. These options still add creaminess to your smoothie, but keep the calorie content lower. They're also high in calcium, providing almost one-third of your daily value. That's good for weight loss, since higher-calcium diets are linked to weight loss, according to a review published in the Journal of Nutrition in 2003.
If you want to cut even more calories, try making your smoothie with iced brewed green tea. It's virtually calorie-free but adds a pleasant and refreshing flavor to your smoothie. To get iced green tea, steep your tea in cold water in the fridge overnight, or brew double-strength hot green tea and pour it over ice before using it in smoothies.
Add a Handful of Fruits and Veggies
Fruits and vegetables should take center stage in your smoothie. Eating more fruits and veggies has serious health advantages, from a lower risk of cardiovascular disease to improved bone health as you age. Fruits and vegetables may also help you lose weight. A study, published in PLoS One in 2015, investigated the diets of more than 550,000 people and found that those who ate more vegetables had a lower chance of carrying too much body fat.
Milder-tasting vegetables -- like spinach, cucumber, yellow bell peppers or baby kale -- let you boost your vegetable intake without significantly affecting your smoothie's flavor. Sweeten your smoothie with a small frozen banana or a handful of frozen berries; then add 1 to 3 cups of vegetables. As you get more used to the taste of "green" smoothies made with leafy greens, you'll be able to increase the amount you add -- or experiment with stronger-tasting greens such as curly kale, romaine, celery, mint or parsley.
While most vegetables are extremely low in calories -- so you can add as much as you want to your smoothie -- fruits contain a moderate amount of calories, which can add up quickly if you're adding several servings to your smoothie. Limit the fruit in your smoothie to keep the calories low; a half-cup to a cup of frozen fruit, or half a frozen banana work well.
Pack in Weight Loss-Friendly Protein
Add a protein boost to your breakfast smoothie to make it more filling. Eating high-protein meals throughout the day might help you shed pounds, according to a study published in Obesity in 2011. When the overweight and obese men included in the study ate a high-protein diet, they lost more weight than the men on a lower-protein diet -- even though both groups ate the same amount of calories. Translation: pack more protein into each meal, and you'll lose more weight without cutting more calories.
Blending protein powder into your smoothie is one way to up your protein intake -- a serving might add 20 to 30 grams of protein, depending on the powder you choose. Look for powders low in added sugar and artificial sweeteners; instead, choose a relatively unprocessed power made with a low-calorie natural sweetener, like stevia. You can also add protein through other healthy ingredients. A 6-ounce container of plain nonfat Greek yogurt, for example, has 17 grams of protein, while a 4-ounce serving of nonfat cottage cheese adds 14 grams of protein to your meal.
Spice Up Your Breakfast
Add a dash of spice to your breakfast smoothie for variety. While spices don't directly cause weight loss, they do add flavor without added fat or sugar, which makes it easier to please your palette without adding tons of calories. They also let you experiment with different flavors, so you don't feel like you're in a "diet rut" and get bored.
Spices also offer other health benefits. For example, ginger might help lower cholesterol levels, which promotes cardiovascular health, according to the University of Maryland Medical Center. Cinnamon might help you respond better to insulin -- one of the major hormones that controls your blood sugar -- according to North Dakota State University. A healthy insulin response may keep your appetite in check. When your body doesn't respond to insulin properly, you're more likely to suffer blood sugar crashes after eating. Those crashes leave you feeling hungry, so you're more likely to overeat. By regulating your body's insulin response, cinnamon might help prevent hunger-inducing blood sugar crashes.
Ginger works especially well in smoothies that contain peaches, mangoes or pumpkin, while cinnamon pairs perfectly with smoothies featuring berries, bananas or pineapple.