The bagel itself.

On Tuesday, we found out that what you put on a bagel changes everything. Eggs and avocado on top cut the rise by more than half compared to the same bagel plain.

Today I'm looking at the bagel itself. Before anything goes on top.

I bought two plain bagels on the same morning. One from a real bakery, baked that day, nothing on the label because there is no label. The other from the supermarket bread aisle, sealed in plastic, a six-pack that had been sitting there for who knows how long.

Same size. Same toaster. No toppings on either one, so I could see the bagel on its own.

They were not the same bagel.

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

Both bagels start with flour, water, yeast, and salt. That part's true everywhere.

But a real bakery bagel usually stops there, maybe with a little malt for browning. It's made to be eaten that day, so it doesn't need anything to keep it soft for weeks. The supermarket bagel does. I checked the label on mine after I ate it, and the ingredient list ran to nineteen items. Added sugar was third on the list, ahead of the salt.

In other words, the supermarket bagel isn't just a bagel with a longer shelf life. It's a bagel with sugar built in, on top of the same refined flour that already puts a plain bagel's glycemic index around 70, according to the University of Sydney's GI database.

So the starch breaks down fast either way. Add a few grams of dextrose or cane sugar on top of that, and there's less room for the rise to stay small.

The fiber tells a similar story. My bakery bagel had about two grams of fiber. The supermarket one had one. Not a huge gap on paper. But fiber is one of the only things in a bagel working against the spike, so even a small drop matters.

I didn't expect the gap to show up on my monitor. It's just a bagel, right? But eighteen points is close to the difference a lot of people are chasing with a whole hack, like a walk after a meal or vinegar before it. Here, it came from something I decided before I even left the house.

Now, I don't think this means every supermarket bagel is a disaster and every bakery bagel is fine. Bakeries vary. Some grocery brands keep the ingredient list short, too. But the label is where you find out, and most people never check.