My wife bought yogurt.

Three kinds, in one grocery run. A tub of plain Greek yogurt. A pack of Activia strawberry cups. And a fruit-on-the-bottom cup, the kind with sweet jam hiding under the white layer.

So I did what any guy with a glucose monitor stuck to his arm would do. I ate them. One per morning, on an empty stomach, nothing else on the side.

Here's why this matters right now.

Yogurt is having a big year. The market research firm Mintel found that US households using GLP-1 drugs like Ozempic eat yogurt at nearly three times the normal rate. Mostly for the protein.

And the dairy aisle has noticed. Just last week, a dairy industry leader pointed to Greek yogurt and cottage cheese as the foods getting the most attention from people on these drugs.

But the word "protein" on a label doesn't tell you how much a cup of yogurt will raise your blood sugar.

So here's the quiz. Which of these three yogurts raised my blood sugar the most?

Make your guess before you scroll…

● The Reveal

The fruit-on-the-bottom cup won. Or lost, depending on how you see it.

That little cup raised my blood sugar about 42 points. The plain Greek yogurt raised it about 9.

More than four times higher.

Here's the thing. None of these yogurts is a "high" glycemic food. A 2017 review in The Journal of Nutrition looked at 93 yogurts in the glycemic index database run by the University of Sydney. Not one scored high. The average was about 34, which counts as low.

But the same review split the yogurts into two groups. The sweetened ones averaged about 40. The plain ones averaged about 27.

In other words, the added sugar is what pushes yogurt up. Plain yogurt on its own barely moves blood sugar.

● The Winner, Up Close

This is one person's experiment, not medical advice. Everyone's body responds differently.

So why did the fruit cup raise my blood sugar the most? Two things work against it.

First, the jam at the bottom is mostly sugar. Second, a fruit-on-the-bottom cup has far less protein than plain Greek yogurt. Protein slows down how fast your body absorbs sugar. Less protein means the sugar reaches your blood faster.

The Activia cup sat in the middle. The strawberry cup I ate lists 9 grams of sugar, 6 of them added, and 4 grams of protein. That cup raised my blood sugar about 27 points.

Not bad. Not great.

By the way… some Activia packs now say that eating yogurt a few times a week may lower your risk of type 2 diabetes, "according to limited scientific evidence." That wording comes from a claim the FDA allowed in 2024. I'd pay close attention to the word "limited."

● The Scoreboard

● The Swap

Love the fruit cup? We don't have to give it up. We can build a better one at home.

Start with plain Greek yogurt. Add a handful of fresh berries for sweetness. You choose how much sugar goes in, not the factory.

Want it sweeter? Stir in a small spoon of jam. You'll probably still use less than the thick layer at the bottom of a store-bought cup.

I don't know if your numbers will match mine. They might not. But the research points the same way: plain, high-protein yogurt raises blood sugar far less than sweet, low-protein yogurt.

Anyway… the kids have already claimed the fruit-on-the-bottom cups. I'm keeping the Greek.

Stay steady