M and I recently had the pleasure of a Buenos Aires visit from Dr. Michelle McMacken and her husband. You can see her BYOL posts here and here.
Naturally, we talked about a lot of different vegany (an excellent term coined by her husband) issues – but don’t worry, we balanced all this with a healthy amount of futbol chatter as well!
One afternoon, Dr. McMacken mentioned that she warns her patients against smoothies (even whole food smoothies). To be fair, she is not alone in this stance: Registered Dietitian Jeff Novick, Dr. C Esselstyn, and all of the Engine 2 folks are also against consuming liquid calories.
She explained that smoothies are a bit of a trap for most of her patients who are seeking to lose weight, because they are often very calorie dense. And because those calories are liquid, people often consume more calories than they would if they were eating the same foods.
However, there are some reasons why I think incorporating smoothies into your diet can be a positive thing.
First, for anyone who is a picky veggie eater, whole-food smoothies can be a great way to sneak in lots of good and healthy veggies into your diet. In fact, Mayo Clinic recommends this for picky children. I recently encouraged a college friend who is trying to change his diet to be more plant-forward to try this tactic as well. Maybe it’s not optimal, but it has helped him to lose a significant amount of weight compared to the SAD diet he was eating (no real contest, I know).
There is also some evidence that certain nutrients become more available to our bodies when the cells are disrupted, ie: pulverizing or blending foods. Now for a long time I thought this was just a marketing exploit of Vitamix and Blendtec, but it turns out, there is some evidence to back it up.
A few studies compared particle size and bioavailability and digestion. They found that many nutrients become more bioavailable when the cells of a nutrient are broken. This is one argument for chewing your food well. But the studies also show that no matter how well we chew, we can never masticate as well as a blender, which can break the foods down to a cellular level. These studies showed that the bioavailability of these foods than became greatly improved, particularly B-carotenoids in carrots, and folate from leafy greens.
Furthermore, back to Dr. McMacken’s point, there is some research that suggests that simply slowing down while consuming liquid calories (soups or smoothies) can significantly help our bodies regulate the amount we are consuming, and the thicker that slowly-drank smoothie is, the longer the person will feel satiated.
Smoothies can also be helpful when you are short on time, or if you are going to a place where you know you will not eat well. Slowly drinking a whole food vegetable-based smoothie before going out can help you get some health boosting veggies in.
Overall, I do agree with Dr. McMacken. Smoothies are an occasional tool and shouldn’t be relied upon. They also may not your best choice for weight-loss.
But that said, I do see a place for mostly (green) vegetable smoothies with some added fruit in a healthy diet. I would recommend avoiding all-fruit smoothies, as well as smoothies with added sugars or juices as this fundamentally changes the discussion.
Beet and Ginger Smoothie
Keeping all of this in mind, today I’m going to share a delicious beet smoothie which I think even Dr. McMacken would love (actually, I’m almost positive she would!) The recipe is mostly credited to M, although I was her taste tester for several versions of this… Please hold your applause.
Not only is this smoothie comparatively low-calorie and veggie-filled, but it also turns out a beautiful rich Malbec red color (come on, I am in Buenos Aires!) and is filled with health promoting nitrates making it an excellent way to start the day or a pre-workout drink.
Beet and Ginger Smoothie:
1 medium-sized red beet – cubbed
½ large cucumber
6-7 large Kale Leaves
10-15 red grapes
2 tbsp chia seeds
2 tbsp lemon juice
1 tbsp maca powder (optional)
1/2” piece of peeled ginger
1 ½ cup of water
Wash and chop all of the ingredients, and place them into your blender.*
Add the chia, maca, and lemon juice along with the water and ice.
Blend until smooth and enjoy
*If you are not using a high-powered blender like the two brands mentioned above, try cutting the veggies into smaller pieces to make it easier for your blender.
Castenmiller, J., C.J. van de Poll, et. al. “Bioavailability of folate from processed spinach in humans. Effect of food matrix and interaction with carotenoids.” Annuals of Nutrition and Metabolism. 44(4) 2000.
de Graaf, C. “Why Liquid Energy results in overconsumption,” Procedings of Nutrition Society, May 70 (2) 2011.
L. Lemmens, S., Van Buggenhout, A.M. Van Loey, et. al. “Particle size reduction leading to cell wall rupture is more important for the B-carotene bioaccessibility of raw compared to processed carrots.” Journal of Argriculture and Food Chemistry. Dec. 22,58 (24) 2010.
Ibrugger, S., M. Kristensen et. al. “Flaxseed dietary fiber supplements for suppression of appetite and food intake” Appetite April, 58 (2) 2012.
As always the information presented in this blog is for educational purposes only. It should not be considered as specific medical, nutritional, lifestyle, or other health-related advice.