Adopting meal replacement shakes is a tricky proposition. The goal is to be healthier. You replace a meal that would be full of sugar, processed ingredients, and probably just too much food. Instead, you consume a smoothie, ideally made of healthy ingredients like fruits and vegetables, with supplements and powders to add substances and make them more filling.
The trouble is, when you're used to eating large meals or meals full of processed ingredients, you're going to have a hard time subsisting just on a shake. These shakes are good, wholesome, and filling, but they might not be quite enough.
If you're used to large meals, a shake won't leave you feeling full on its own. If you're used to meals full of sugar, your shake might not satiate the craving for that sugar and leave you wanting more. You end up feeling like the shake was just a snack or an appetizer, and eat more later when you feel the cravings again.
So what can you do to make your shakes a bit more filling, to reduce cravings and hunger pangs? Here are five options. Note that these options are often mentioned elsewhere, but we're going into deeper detail to explain why and how you can add these ingredients. Don't just skim the subheads!
1. Nut Butter
One of the most common additives to smoothies is a nut butter. You have a few different options here, but they all provide the same benefits. First, they thicken up the smoothie. This means it won't turn to liquid as quickly, and will feel more filling as you drink it. Second, they're packed with protein, which is inherently more filling than vegetable matter and fruit, which is largely water and natural sugar. Third, they often add a bit of earthiness to the smoothie, which makes it taste and feel a bit more filling.
Peanut butter is the most common form of nut butter for smoothies, and you have a lot of different options. Crunchy peanut butter isn't recommended, because you're blending it up anyway, so all you're doing is making a worse texture for yourself. Conversely, we recommend avoiding some of the more heavily processed peanut butters, because they're full of preservatives. We're looking at you, Jif. Look for a more organic or fresh-ground peanut butter. You can even get honey-roasted peanut butter for a bit of extra sweetness.
Almond butter is probably the second most common alternative, and it's a fantastic choice. Almonds are high in protein and fiber, both of which fill you up and keep you full longer, meaning it's a great choice for smoothies. Almond butter also adds a unique flavor to a smoothie, and plenty of vitamins and minerals.
Cashew butter is one of our favorite options. Cashews are a wonderfully smooth nut themselves, and they're high in plenty of different vitamins and minerals. Plus, the nut also has tryptophan, which your body uses to make serotonin, a beneficial mood neurotransmitter.
Hazelnut butter is interesting. Hazelnuts are often added to chocolate – and chocolate flavored smoothies – to give depth to the chocolate flavor. Picking up a good hazelnut butter can give your smoothies a robustness you wouldn't think possible, normally.
Pecan butter is one of the more rare options among nuts, so you might end up needing to make it yourself rather than finding it on store shelves. Pecans are more of a savory nut, and are packed with a ton of nutrients to make your smoothie that much healthier. They're full of antioxidants as well. The only downside is their slightly bitter aftertaste, which might not sit well with you if you're sensitive to it.
Regardless of which nut butter you choose, add 1-2 tablespoons to your smoothie and you'll add heartiness, nutrients, and fiber to keep you full.
2. Fat
"But the point of the smoothie is to help lose fat, why would I add fat?" Well, fats are packed with energy and are very nutrient-dense. That's part of why they're so filling, and by adding a little fat to your smoothies, you can make them much more filling without boosting your caloric intake all that much.
Now, we're not talking about trimming up a side of bacon and tossing it into your green smoothie, as delicious as that might be. No, there are healthier fats you can add without risking your cholesterol or your heart. 
Good fats provide you with the essential fatty acids your body needs to absorb vitamins, which makes your smoothies give you even more nutrients than they were before. They help with skin suppleness, protect your heart – good cholesterol is beneficial, after all – and they help prevent hunger cravings shortly after consuming the smoothie.
There are a few different ways you can add some fat to your smoothie without giving it a cloying, sticky taste. Try to add just a tablespoon or two, in place of the liquid you normally use as a smoothie base.
Coconut oil is one of the best healthy fats you can add to a smoothie. It's generally recognized as an appetite suppressant on its own, and it has a delicious, slightly sweet flavor that helps back up the rest of your smoothie ingredients.
Flaxseed oil is one of the few plant oils that includes a huge boost of omega-3 and omega-6 fatty acids, which your body needs for a variety of reasons. Unlike a fish oil supplement, flaxseed won't give you a fishy taste or after-effects.
Avocado, whole, is a buttery fruit that goes great in both fruit-based and veggie-based smoothies. Avocado includes plenty of monounsaturated fats, which are about the healthiest kind of fat you can find, and they help make your smoothies creamier.
Also, cashews have plenty of omega-3s in them as well, so if you choose, you can add some cashew butter to cover two birds with one healthy fat.
3. Oats
If you've ever tried to add oats to something without quite preparing them right, you probably recoiled from this suggestion. Oats, when used incorrectly, are pretty unpleasant. They don't blend well because they're soft, and they don't have time to absorb liquid from a smoothie before you drink it, so you end up with tough little bits of oat while you're trying to drink something smooth. Plus, depending on the kind of oats you get, you might be adding a lot of ground oat residue. That powdery oat substance that settles to the bottom of every package of oats ends up tasting more like cardboard and sawdust. Needless to say, it's not something you want to add to your smoothies, right?
Well, there are better ways to add oats. First of all, remember that one of the more commonly available kinds of oats is steel cut oats. Steel cut oats are the least processed form of oats, using the full oat grain sliced into pieces. It has a lot of the tough bran part of the oat. They're great for things like no-bake cookies and other oat-based cookies, but not so much for anything you want them to blend in.
No, the kind of oat you want to find are rolled oats. Rolled oats are processed by grinding them with large rolling stones or disks. They're dehusked and slightly steamed, rolled out into flakes, and slightly toasted. This makes them flatter and, most importantly, they much more readily absorb liquid.
You can also opt to use instant oats instead of rolled oats, if you want. They're quite similar, but instant oats are processed such that they're easily cooked in a few minutes, to make instant oatmeals and other meals. They might not work as well in a smoothie, but it's really down to personal preference and how readily you can get rolled oats locally.
Adding your oats directly to the smoothie when you blend it up gives it a thickening effect and a bit of oat flavor, but might be a bit too thick depending on what else you have in your smoothie.
Alternatively, you can grind up the oats into a bit more of a powder before you add it. This makes it more like a fiber powder additive, and will make it blend much more nicely with the smoothie. If you really don't like getting bits of chewy oat in a sip of smoothie, this is the best option.
You can also soak your oats in some milk for a few hours or overnight before making your smoothie. This will make them quite soft and impact the flavor of the milk into them, but it won't thicken your smoothie as much.
4. Seeds
Nuts and seeds are different kinds of foods, and they serve different roles in a smoothie. While nuts will add vitamins, minerals, fiber, and protein, seeds add vitamins, minerals, antioxidants, and healthy fatty acids.
Chia seeds are one of the most commonly recommended superfood seeds to add to modern smoothies. They're tiny and tough, so we recommend soaking them in water or milk for a few hours to soften them up before adding them. They turn into an almost pudding-like consistency and you'll never notice the tiny, tough bits.
Sesame seeds have a unique flavor that some people love and others hate. If you like it, these seeds give a bunch of useful minerals, including magnesium and zinc. You can add them whole or grind them up for your smoothie additive.
Hemp seeds are a relatively new superfood trend, though they've been around for centuries. They add a bit of a grassy flavor, which you won't even notice in a green smoothie, and have both healthy fats and a bunch of minerals in them. Add a spoonful or two to a smoothie for a great boost in nutrients to keep your body happy.
Pumpkin seeds are larger and will require shelling and/or grinding before you add them to a smoothie. They're worth the effort, though, because they're absolutely packed with nutrients, minerals, and antioxidants. They also have some carbohydrates, which will help you feel full and give you energy for hours.
5. Legumes
Legumes, or beans, are a great addition to smoothies.
Wait, no, come back, hear us out. They're great, really! We're all used to beans in savory meals and in hearty dishes, but they actually go well in smoothies, particularly when you blend them up. You don't necessarily get a lot of bean flavor, but they have plenty of protein, vitamins, minerals, and nutrients your body loves.
You can't just dump beans in a smoothie and go to town, though. Soak and drain a quarter cup of beans for each smoothie – you can prepare them ahead of time – and cook them before you add them. You can prepare enough beans for a week all at once, and add them bit by bit each day. Blended up properly, you'll never know there were beans in your smoothie at all.
The primary benefit of adding beans is the fiber content. Fiber slows down your digestive processes, which means your body takes longer to digest what you eat. The longer it takes to digest your food, the longer it will be before you feel hungry again. Thus, a simple serving of beans makes your smoothies last that much longer.
What about you? Tell us in the comments what your favorite smoothies are. Recipes welcome!
