plant fuel

Anatomy of a Smoothie Part 1: Plant Protein for Post-Run Recovery

One of the major stumbling blocks among athletes wanting to make the switch to a plant-based lifestyle is the notion that plants don’t offer enough protein and that plant proteins are incomplete. Although the latter is mostly true, it is easily remedied by eating a variety of foods so that these incomplete proteins can find each other in your GI tract and combine to form complete proteins. Food combinations don’t even have to be rigidly timed; just eat a variety of foods on a daily basis, and your body will take care of the rest.

(Psst: I wrote a guide on plant protein for runners that’s free to download. Just type your name and email address in the pop-up if you haven’t already!)

How much protein do you need?

As a runner, this will probably vary throughout your training cycle. Most people don’t need anywhere near as much protein as they think they do, and the excess does little besides overwhelm the kidneys. More on that topic here.

To answer the question of how much you actually do need as an athlete, the Academy of Nutrition and Dietetics provides the following:

While athletes’ protein needs are greater than that of non-athletes, they’re not as high as commonly perceived. The Academy of Nutrition and Dietetics, Dietitians of Canada and the American College of Sports Medicine recommend 1.2 to 2.0 grams of protein per kilogram of body weight per day for athletes, depending on training. Protein intake should be spaced throughout the day and after workouts.

Source: Academy of Nutrition and Dietetics. Protein and the Athlete – How Much Do You Need?

Smoothies are a great way to get your plant protein throughout the day: they taste great, you can drink one after a run that has left you feeling so dehydrated that you don’t want solid food, and they make tasty, healthy treats throughout the day. Therefore, I’m taking the deep-dive approach this week, the first in a four-week series on the health benefits of common smoothie ingredients, and presenting a variety of sources of plant protein that make great smoothies. Below I discuss how much protein they provide individually and how to increase a smoothie’s total protein content by combining ingredients to reach the desired level as part of a diet that also provides protein from other sources such as beans and whole grains.

So let’s dive in!

Plant Protein for Smoothies

Almond butter

Nut butters like almond butter and peanut butter are a decent source of protein, but they are really not as rich in protein as you might expect: 2 tablespoons of almond butter, the standard serving size on nutrition labels, provide just 4 grams of protein. The good news? A typical smoothie recipe recommends ¼ cup (equal to 4 tablespoons, or double the amount described above) of nut butter for a total of 8 grams of protein.

This same amount also provides a whopping 38 g of fat (79 calories or 9.5 g per tbsp according to Self Nutrition Data), which may be a bit off-putting for someone with a weight-loss goal. Either way, take heart in the fact that almonds are one of the better plant sources of omega-3 fatty acids, so you can still benefit by adding the almond butter to your smoothie anyway and finding other ways to trim fat from your diet (like sautéeing with veggie broth, white wine or soy sauce instead of oil).


vegetarian juice on table
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Spinach, according to various sources, contains 2 grams of protein per 1.5-cup serving fresh or half-cup raw. Basically, 2 grams of a 100-gram serving are protein. This may not sound like much, but to make a green smoothie with fresh spinach as the only “green” ingredient, you’ll want to use at least double that amount. So, the spinach alone will give you 4 grams of protein, and you can easily increase the total protein content of your smoothie by combining any of the other ingredients we go over in this post.

A green smoothie made with 3 cups of fresh spinach leaves will also give you 160 percent of your recommended daily intake of vitamin A, 80 percent of your daily vitamin C, 30 percent of your daily iron (although there is some disagreement as to whether the bioavailability makes it a good source of iron, hence its omission from my recent article on plant-based iron for runners), and 1,020 percent – that’s right, 10 times! – your daily vitamin K intake. Trail-running friends with scraped knees and elbows, that’s a lot of clotting power.


green plant
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Kale seems to come in pretty close to spinach in terms of protein by weight: 2.9 g of protein per 100g total. Again, it doesn’t sound like much, but when combined with other good-for-you ingredients, it can help you get your protein intake where it needs to be.

I’ve done some experimenting and found that, whereas spinach has a mildly sweet flavor that disappears pretty quickly into smoothies with frozen bananas and other sweet ingredients, the sulphuric flavor of kale is not as easy to mask. To date, the only thing I’ve found that does the job is frozen pineapple. So if you want to make a kale smoothie and/or use up some kale without cooking it or wilting it for a salad, just drop it in your blender or food processor with at least a cup of frozen pineapple (which adds nearly double your daily vitamin C requirement!) plus one sliced room-temperature banana for a shot of potassium and high-quality carbs.

Ground flaxseed

A quick note about flax seeds vs. ground flaxseed: while you might be able to save money buying flax seeds whole, unground flax seeds will pass through you mostly undigested. If you want to reap any of the nutritional benefits, make sure to grind them before using (I used to do this in a coffee grinder before I got lazy and started buying it ground).

Flax seeds boast numerous nutritional benefits, including being high in alpha-linolenic acid or ALA, the omega-3 fatty acid most commonly found in plants (we’ll talk more about omega-3 in an upcoming post).

A 2-tbsp serving of ground flax seeds provides 3 g of protein. Again, not much if that’s the serving you’re using, but going up to 3 or even 4 tbsp will increase the protein content of your smoothie. In my experience, adding ground flaxseed is a great way to thicken a green smoothie, especially if you’re foregoing almond or peanut butter.

Soy milk

soya beans and milk
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The slogan really should be “soy milk: it does a body good.” Soybeans are naturally rich in calcium, and by volume, soy milk contains nearly the same amount of protein as dairy milk (7 g in soy milk vs. 8 g in dairy milk) and none of the cholesterol or yucky hormones to throw you out of whack. But we’ll go there another day.

If you figure that you will use at least a cup, or in many cases 1.5 cups, of soy milk to make a smoothie, that’s 7 to 10 grams of protein right there. By adding in any of the lower-protein items above, you can make a very tasty smoothie and raise the protein content pretty quickly to 20 g or whatever your magic number happens to be.


Just like soymilk, tofu is an excellent source of plant protein. According to this source, half a cup of the firm kind contains 10 g of protein. Unlike soy milk, most people don’t think to use it in their smoothies! This is honestly something that I stumbled upon one day when my refrigerator was empty except for a block of tofu, some tart cherry juice,  some mixed berries in the freezer and a couple of other things. Necessity being the mother of invention, I took a chance on these few items making a decent smoothie and it turned out great!

Tofu is a great way to add protein and thicken a smoothie and can solve various smoothie dilemmas, like being fresh out of bananas or wanting (or needing) to use a fruit juice for the liquid in place of soy or another plant milk. It whips up quickly in a food processor and has a nice creamy consistency when blended all by itself. To make a smoothie, you can drop in a quarter or a third of a block in chunks along with the rest of the ingredients and hit the “on” button just like any other smoothie.

Protein powders

These are considered by many to be the mac-daddy ingredient of a protein smoothie or shake. There are a lot of different kinds out there, and my two defaults are Huel and Amazing Grass. Huel is actually sold as a nutritionally complete protein shake with 36g of protein per cup of dry mix. When I want to add protein to a fruit smoothie, I’ll often just drop in ¼ cup of Huel and also use soy milk and/or chia seeds or flax to get to two digits. Amazing Grass comes with a scoop, and one scoop of the Green Superfood variety contains 20g of protein. Since the price tag for these and other protein powders is a bit higher than the ingredients discussed above, I typically save them for recovery from a Saturday training run of 18+ miles. Frozen berries are ideal in a smoothie with the Green Superfood because the end result is similar to a berry-spinach smoothie.

Word to the wise: Combining a concentrated protein powder with soy milk can cause your concoction to glob up. When making smoothies with a product like Amazing Grass, use fruit juice and/or a low-protein plant milk (almond, flax, rice, whatever) in order to achieve a drinkable consistency!

So what are some of your favorite smoothie combinations for added protein? Questions about protein requirements and how to meet them? Hit me up in the comments!


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