Thick and Creamy Weight Gain Smoothie

A weight gain smoothie should be something you actually want to drink, not a chalky afterthought you force down. This one gets it right by sticking with classic flavors—peanut butter, banana, and a little honey—while packing close to 800 calories into a single glass.

It’s made with whole milk, Greek yogurt, and rolled oats blended so smooth you won’t know they’re there. No gritty texture, no weird aftertaste, just a thick, milkshake-like drink that keeps you full for hours.

What Makes This Smoothie So Effective

The base is simple: banana and peanut butter. Together they create a creamy, naturally sweet flavor that masks the oats and protein powder completely. You get the calories without the struggle.

Whole milk and full-fat yogurt bring in around 250 calories on their own, plus enough protein to make this genuinely filling. A scoop of protein powder pushes it further, but even without it you’re looking at a solid 650 calories from real food.

The rolled oats are what make it stay with you. They blend in entirely and add slow-digesting carbs, so you aren’t hungry an hour later.

Ingredients

• 1 ripe banana, frozen: frozen makes the smoothie thick and cold without diluting it
• 2 tbsp creamy peanut butter: natural or regular both work, and they add healthy fats
• 1/4 cup rolled oats: raw rolled oats blend up smoothly; no need to cook them first
• 1 cup whole milk: whole milk gives the richest base; 2% works but you’ll lose some calories
• 1/2 cup plain full-fat Greek yogurt: adds tang, protein, and extra creaminess
• 1 tbsp honey: for a touch of sweetness; maple syrup works too
• 1 scoop vanilla or unflavored protein powder (about 30g): optional, but it boosts the protein to around 33 grams
• Pinch of salt: wakes up all the flavors

Variations / Substitutions

• Dairy free: swap the whole milk for oat milk and use a coconut-based yogurt. The total calories will drop slightly, but the texture stays creamy.
• Chocolate version: add 1 tablespoon unsweetened cocoa powder along with the protein powder for a chocolate peanut butter spin.
• Greens add-in: toss in a small handful of fresh spinach. You won’t taste it, and the color stays surprisingly appetizing.
• Different nut butter: almond butter or cashew butter makes a good swap and changes the flavor just enough to keep things interesting.

If that chocolate version sounds good, you might also like a high-calorie strawberry smoothie with cashew butter.

How to Make This Weight Gain Smoothie

Step 1: Blend the Liquid Base

Start by adding 1 cup whole milk, 1/2 cup plain full-fat Greek yogurt, 1 ripe banana (broken into chunks), 2 tablespoons creamy peanut butter, 1 tablespoon honey, and a pinch of salt to a blender. Blend on high for about 30 seconds until the mixture is completely smooth and you can’t feel any banana pieces on a spoon.

Step 2: Pulse in the Oats and Protein

Next, add 1/4 cup rolled oats and 1 scoop (about 30g) of protein powder. Pulse the blender a few times to get things moving, then blend on low speed for 20 seconds, or until the oats are broken down and the smoothie looks thick and uniform. Stop and scrape down the sides if needed—any stuck clumps will disappear with another quick blend.

Step 3: Pour and Serve

Give the smoothie a taste and adjust if you need to—a little more honey for sweetness or a splash of milk if it’s thicker than you like. Pour it into a tall glass and drink it right away while it’s still cold and frothy. It’s ready in under 5 minutes.

A Few Notes Before You Blend

• Freeze the banana ahead.: A frozen banana makes the smoothie thick and cold without watering it down. Peel and slice it before freezing so it blends more easily.
• Soak the oats if your blender is weak.: Let them sit in the milk for 10 minutes before you start. It softens them and prevents any hint of grittiness.
• Don’t over-blend.: Once everything is smooth, stop. Over-blending can warm the smoothie from the motor’s friction, and you want it frosty cold.
• For extra calories, add a tablespoon of coconut oil.: It blends in completely, has almost no taste, and adds over 100 calories without changing the texture.

To make two smoothies at once, just double everything:

Frequently Asked Questions

Do I need the protein powder?

No. The smoothie still clocks around 650 calories without it, and the yogurt and milk provide protein on their own. It’s there if you want a boost, but the texture works either way.

Can I use instant oats instead of rolled?

Yes, instant oats dissolve even more quickly and won’t cause grittiness. The smoothie might feel slightly less thick, but the flavor stays the same.

How do I make it even more calorie-dense?

Add a tablespoon of coconut oil or a small handful of almonds before blending. Both add calories without a noticeable taste shift, and they blend in smoothly.

Can I make this the night before?

Yes, it keeps in the fridge overnight in a sealed jar. It will thicken as the oats absorb liquid; just shake it with a splash of milk in the morning to loosen it back up.

Weight Gain Smoothie Recipe

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Prep Time 5 minutes mins

Total Time 5 minutes mins

Servings: 1 servings

Calories: 800

Ingredients Method Notes

Ingredients

  

• 1 ripe banana, frozen
• 2 tbsp creamy peanut butter
• 1/4 cup rolled oats
• 1 cup whole milk
• 1/2 cup plain full-fat Greek yogurt
• 1 tbsp honey
• 1 scoop vanilla or unflavored protein powder (about 30g)
• Pinch of salt

Method

 

1. Add the milk, yogurt, banana, peanut butter, honey, and salt to a blender. Blend on high for 30 seconds until smooth.
2. Add the rolled oats and protein powder. Pulse to combine, then blend on low for 20 seconds until thick and uniform, scraping down the sides if needed.
3. Taste and adjust, then pour into a glass and drink immediately.

Notes

If you don’t have a frozen banana, drop in a few ice cubes to keep it cold. The smoothie is naturally thick; add a splash more milk if you prefer a thinner consistency. It’s best fresh but can be refrigerated overnight—shake with a little milk to revive it.