Pop quiz.

Same fruit, three different forms. A glass of juice. A blended smoothie. And the fruit itself, sitting whole on the counter.

Which one raises my blood sugar the most?

Most people guess the juice. It's liquid sugar, no fiber, easy to gulp down fast. That part is true. But a study published this fall looked at real people, not lab tests, and found something that surprised even the researchers. The group who drank fruit smoothies regularly had the highest rate of high blood sugar of the three groups. Higher than the juice drinkers. Higher than the people who just ate whole fruit.

So before you guess, here are your three options.

● Guess the Biggest Spiker

The smoothie wins. And that trips people up, because blending doesn't strip out fiber the way juicing does. A smoothie still has the pulp in it. So why does it raise blood sugar more than a plain glass of juice?

Portion size. A typical smoothie blends together two or three bananas, a cup of mango, a handful of pineapple, maybe some honey for taste. That's four servings of fruit in one cup. And you can drink the whole thing in under two minutes.

Nobody sits down and eats four bananas and a cup of mango in one sitting. It would take forever, and you'd feel sick halfway through. But blended into a drink, it goes down easy. The fiber is still technically there. It just can't do its job fast enough to keep up with that much sugar hitting your system at once.

In other words, the blender isn't the problem. The portion is.

It's volume dressed up as health.

Here's what that smoothie did on my glucose monitor.

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

● The Scoreboard

So what do you do with this? You don't have to give up smoothies. I still make them.

The swap is simple. Cut the fruit down to one, maybe two servings, not four. Then add something with protein or fat, like Greek yogurt or a spoon of nut butter. That slows down how fast the sugar hits your bloodstream, and it makes the drink filling instead of just sweet.

Tomorrow, we'll put that exact rebuild to the test. Same blender, half the fruit, double the staying power.

Stay steady