What goes in a good smoothie?

A good smoothie has five parts: about a cup of milk or soy milk, enough protein to reach your meal line (30 g at 165 lb), one or two portions of frozen fruit, a spoon of chia, flax or oats, and a little peanut butter if you like. Put them in that order and blend for about a minute.

Most people build a smoothie by taste. A banana, some berries, a splash of juice, maybe a spoon of honey, and a handful of whatever fruit is going soft. It tastes great, and the more fruit goes in, the healthier it feels. That’s the glass that leaves you hungry by ten, because it’s fruit and water with almost nothing else.

Build it like a plate

Think of how you’d build a dinner plate: a protein, some plants, maybe a little fat. A glass works the same way. A glass of only fruit is a fruit salad with a straw. It’s lovely next to a meal, but it isn’t one.

A fruit portion is a medium banana, about a cup of frozen fruit (150 g), or two Medjool dates. That’s our rule, and we stop at two portions because two already bring about 20 to 37 g of sugar.

The protein

This is the part to get right. US adults eat about 77 g of protein a day, and only 19% of it at breakfast, which is about 15 g, according to USDA’s What We Eat in America survey. Your meal line is about 0.4 g per kg of your body weight, rounded to 5: 25 g at 140 lb, 30 g at 165 lb, 35 g at 180 lb and 40 g at 220 lb. The Gyroscope app personalizes yours.

Milk already brings 8 g. Then pick one:

• Greek yogurt. 7 oz of plain nonfat Greek yogurt has 20 g of protein in 117 calories, and it makes the glass thick and tangy.
• Cottage cheese. Half a cup of 1% has 14 g, a full cup 28 g. Blended, the curds disappear. It’s salty, with 459 mg of sodium in half a cup.
• A scoop of whey. A 32 g scoop has 25 g of protein in 113 calories. Scoops differ by brand, so go by the grams on your label.
• Tofu and soy milk. Half a cup of firm tofu has about 22 g in the USDA record, but tofu labels vary a lot, so check yours.

Why a smoothie needs protein has the reasons and what 30 g looks like in each.

The fruit, frozen

Frozen fruit does the job of ice and keeps the flavor. The US guideline says frozen fruit “with no or very limited added sugars” is a good option, and it waits in the freezer until you need it, so it’s what we use. Freeze bananas peeled and in halves, so they go straight in.

Two numbers surprise most people. One Medjool date has 16 g of sugar, more than a medium banana (14 g). And a cup of 2% milk has 12 g of sugar, more than a cup of frozen strawberries, though none of the milk’s sugar counts as added. How much sugar is in a smoothie explains which sugar counts.

The fiber

US adults average about 16 g of fiber a day, by the same USDA survey. A smoothie is an easy place to add some, since seeds and oats disappear in the blender.

A tablespoon of unsweetened cocoa has as much fiber as a quarter cup of oats, about 2 g, for 12 calories against 76. Half an ounce of chia has 4.9 g and thickens the glass the longer it sits. And a cup of raw spinach brings 145 mcg of vitamin K, 121% of the Daily Value, for 7 calories, and it’s easy to hide under fruit.

Thickness counts for more than texture. In a 2016 study of 15 young men, a thick 100 calorie shake felt fuller 40 minutes later than a thin 500 calorie one. Why a smoothie doesn’t fill you like food has that study.

The order in the jar

1. Liquid at the bottom, so the blade spins freely.
2. Protein: yogurt, cottage cheese or the scoop.
3. Frozen fruit.
4. Seeds, oats or cocoa.
5. Greens on top, where the fruit pushes them down.

Blend for about a minute. If it’s too thick, add a splash of milk. If it’s too thin, add more frozen fruit, a spoon of oats or chia, or less liquid next time.

One glass, part by part

The strawberry banana yogurt glass is the simplest meal in the top ten.

It clears all six meters in Build your glass for an A. The cup of strawberries brings about two thirds of the day’s vitamin C, and the milk and yogurt together bring more than the day’s vitamin B12. It costs about $2.73 at US average prices. The recipe page has it in grams.

What to leave out

• Juice. A cup of orange juice adds 21 g of sugar and half a gram of fiber. Use milk or water.
• Honey, syrup and table sugar. The US guideline counts all of them as added sugar, and one tablespoon of honey is 17 g, past the 10 g it allows a whole meal.
• Ice cream, sherbet and sorbet. They make it a milkshake.
• A third portion of fruit. A banana, a cup of strawberries and a cup of mango come to about 44 g of sugar, with no more protein.