Colors: As a general rule, fruits and vegetables that are deeply colored tend to be more densely packed with phytochemicals. This is particularly true for green leafy veggies. Dark greens, like arugula or kale, are usually a better choice than pale greens like iceberg. Now, this isn’t always true, of course - don’t sleep on light-colored phytochemical powerhouses like cauliflower!

Use the skin: Incorporate skins and peels as much as possible in your smoothies. Phytochemicals are concentrated in the outer tissue of plants. For instance, don’t peel carrots, cucumbers, apples, etc. when adding them to the blender. When using citrus fruits, leave as much of the albedo (the white spongy part between the pulp segments) as possible - you will get many times more phytochemicals that way.

Primary Sources: Most fiber will come from the plants incorporated in the smoothies.

Functional Additives: Acacia, oatmeal, oat bran, flax meal, or chia seeds.

Amount: About 6-10 grams of fat. Adding five halves of walnuts, or around a quarter to a half of an avocado is enough to substantially improve absorption of lipid-soluble nutrients like lutein and beta-carotene.

Prefer whole plant fat sources: We want to use nuts, seeds, and avocados, which are predominantly unsaturated fats and come with phytochemicals and fiber. Oils, in contrast, add a lot of calories but relatively few nutrients.

Freshness: Plants vary in how they respond to storage, but in most cases, fresher is best. Cruciferous vegetables, green leafy veggies, berries, and other delicate plants are significantly more nutritious when consumed close to when they were harvested.

Sourcing: Securing your ingredients from a local source (like a farmer’s market or CSA) is a great idea for these delicate items if you can manage it, to minimize time spent in transportation and storage. For more hardy produce, like butternut squash, this is much less of a concern.

Frozen: Commercially available frozen veggies have typically been blanched prior to the freezing process. This means that any frozen vegetables you purchase have, in effect, been cooked. They’re still very good for you but many of the same caveats that we described above with respect to cooking will apply here.

Chopping: Some plants, like lettuce and cruciferous vegetables, generate more phytochemicals immediately after being cut. If you can plan in advance, try chopping them up beforehand, but make sure to use them within 24 hours of this preparation.

Steaming: Many vegetables are at their most nutrient-dense when consumed raw. This is especially true of cruciferous vegetables, which contain cancer-fighting chemicals that are sensitive to heat. This obviously does not apply to winter squash and other plants that must be cooked. However, certain nutrients (carotenoids) are actually unlocked from plant cells and are easier for your body to access when cooked. This applies to most carrots, tomatoes, and some other red/orange veggies. If you choose to cook vegetables before using them in smoothies, research suggests that boiling removes the most nutrients (unless you also use the boiling liquid). Steaming is the best bet. For most veggies (especially crucifers) you should only steam them for less than five minutes to preserve nutrients and ensure the best flavor.

Liquid: Add at least half a cup of liquid to your smoothie first the add more when blending. How much fluid to add is ultimately a matter of personal preference and your blender’s tolerance level. The more you add, the thinner the smoothie will be. In most cases, you will want to use plant-based milk. Unsweetened cashew milk is probably the best bet - it has a neutral flavor and creamy texture - but there are tons of options out there that you can try. For thinner smoothies, coconut water is a great choice - high in electrolytes and adds a mild sweetness and aroma.

Base: Most smoothies need a base, and that base will usually be a “creamy” fruit - bananas are the most common choice. You can also use mangos, peaches, avocados, pears, pumpkin, butternut squash, and a few others. Try freezing them beforehand to increase thickness. Watermelon, berries, and other water-rich fruits won’t work for this purpose.

Fruits & veggies: Now, you can add other fruits and veggies for extra flavor and nutrition. This is when you want to throw in berries, greens, and other watery constituents. This is the fun part, where you can figure out complementary combinations of fruits and vegetables.

Fats and protein can contribute thickness to a smoothie, as well as nutrients. Avocado, coconut meat, chia seed pudding, cacao/cocoa, yogurt, and protein powder, all work to add body to a smoothie. These are also more calorically dense, so be mindful of portions, and weigh/measure depending on your goals.

Salt: A small amount of salt can be surprisingly tasty in some recipes. I like big flakey salts like Maldon but you can use whatever you like.

Spices are packed with a stunning amount of phytochemicals relative to their weight. I recommend cinnamon, ginger, nutmeg, and cardamom.

Flavor extracts and baker’s emulsions can add a lot of flavor without adding calories.

Sweetener: Add to taste if you feel the smoothie needs it, just don’t go crazy. I like liquid stevia, especially stevia glycerite.