This metabolism booster smoothie is like jet fuel for your metabolism.
I drink smoothies all the time, and am always looking for new combinations to dress up my favorite green smoothies. Grapefruit has become a favorite! I love grapefruit, but buy it… then let it sit in the bottom drawer of my fridge for ages because I never feel like taking the time to cut the sections. Now, I just cut them up, remove the peel and any excess pith, and freeze. By itself with spinach, it makes a very tart smoothie (I enjoy them though!). For this smoothie, I took advantage of some other fruits with great metabolism boosting effects to sweeten it up and make it even more delicious.
Studies have shown eating grapefruit or drinking grapefruit juice, without any other dietary changes, results in weight loss. However, people who eat fresh grapefruit lose more weight than juice drinkers. In this smoothie, the whole grapefruit is eaten, rather than just extracted juice.
Pineapple is high in vitamin C, a compound important for a healthy metabolism. Vitamin C deficiency lowers your body’s ability to oxidize fat. This leads to fatigue, and retention of body fat. One cup of pineapple has 131% of the RDA of vitamin C! This smoothie recipe has over 200%.
I freeze bananas for smoothies and to add to my yogurt while they are still green (they are good– it just takes a bit getting used to since they are less sweet). The reason for this is green bananas are higher in resistant starch, and lower in simple sugars. Our bodies can’t break down resistant starches, but they help the body absorb vitamins and minerals (especially calcium, ladies!), and inhibit the growth of disease-causing bacteria. Those are great benefits alone, but the other great benefit is that your body can only extract half the amount of calories from resistant starch than from other types of starches (this doesn’t mean your green banana has half the calories of a ripe one- because the whole banana isn’t made entirely of resistant starch or sugar).
Anyone who has drank a smoothie with a scoop of whey protein powder knows the belly-filling effect of protein. However, the benefits of protein to weight loss go beyond satiety. Our bodies have a more difficult time holding on to calories from protein, meaning we burn more calories digesting it than calories from carbohydrates or fats. One high protein smoothie isn’t going to have a huge effect on weight loss, but studies show that increasing protein intake over long periods of time has a significant impact on weight loss. Studies suggest that a protein shake with about 160 calories, and 25 grams of protein, can increase metabolism by 25%!
Spinach is actually more nutrient dense than kale. Calorie for calorie, spinach has 50% more protein, almost 350% more iron, and 30% more calcium (Kale does win the “nutrient battle” for Vitamin C!- so I wouldn’t say give up on kale just yet. It’s still super nutritious).
All the time, we hear that green tea is good for our metabolism, but why exactly? Caffeine does have a positive effect on our metabolisms, but the powerful component of green tea is a compound called ECGCs. ECGS have a thermogenic effect that increase fat burn in the liver, and also inhibit lipase, an enzyme that absorbs fat in the digestive tract. In addition to all of that, green tea has been proven to increase satiety, making you feel less hungry.
If all that hasn’t convinced you to get in the kitchen and make this smoothie, let me just tell you IT’S DELICIOUS! And an eye opener. I’m struggling to get through the day because I just couldn’t sleep last night, and one sip of this smoothie has perked me up a lot.
- ½ cup strong brewed green tea
- ¼ cup coconut milk
- 1 cup pineapple (frozen)
- 1 unripe banana (frozen in quarters)
- 1 large grapefruit (peeled, chopped, and frozen)
- 70 g spinach, frozen (you can use fresh, but the smoothie won't be as thick)
- 4-5 large ice cubes
- 10 g plain whey protein (or favorite protein powder)
- Add the liquids first, then the rest of the ingredients to a blender. Blend well, until the greens are well blended into your smoothie.
- If you don't like your smoothies thick (I like mine super frozen and thick), add more liquid, or omit the ice.
- The spinach I use comes frozen in ice-cube sized pieces. I use 7 frozen cubes.
Oranges also work well in place of the pineapple.
The Effects of Grapefruit on Weight and Insulin Response, US National Library of Medicine
Vegetables and Fruits, Harvard School of Public Health
Pineapple Nutrition Facts, Nutrition Data
All About Resistant Starch, Precision Nutrition
Ripe vs. Unripe Bananas, One Green Planet
How to Raise Metabolism, eMed Expert