My daughter grabbed a bunch.

Grapes, straight from the fridge. She calls them nature's candy. I've heard other people say the same thing.

Is that true? I decided to find out.

I ate a cup of red grapes on an empty stomach and let my glucose monitor watch what happened.

Here's the result.

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

My blood sugar rose about 38 points.

Not nothing. But nowhere near what actual candy does.

Grapes sit in an odd middle spot. The University of Sydney's glycemic index database puts red grapes somewhere between 43 and 59, depending on the batch tested. Nutrition scientists call that "moderate." Not low, like berries. Not high, like a candy bar.

In other words, grapes will raise your blood sugar. Just gently, if you keep the portion reasonable.

Here's why. Grapes carry two kinds of sugar, glucose and fructose, wrapped up with fiber and water. The fiber slows down how fast your gut can pull that sugar into your blood. And fructose doesn't raise blood sugar directly the way glucose does. It heads to your liver first, so it takes a slower road into your bloodstream.

So the rise comes on softer than a straight shot of table sugar would.

A study published last year in Nature Medicine tracked how differently people respond to the exact same food. The gap between one person and the next was huge... the same cup of grapes could land two completely different ways depending on who ate it.

So take my 38 points as one data point. Not a universal rule.

There's another number worth knowing here: glycemic load. A cup of grapes carries a glycemic load of roughly 8 to 11. That number folds in both the GI and the actual portion size, and it's a better real-world guide than GI alone.

Here's why that matters. A cantaloupe has a high GI, higher than grapes. But you'd have to eat almost the whole melon to get the same amount of carbs as one cup of grapes. So on your actual plate, at your actual portion, the melon barely moves the needle. GI alone can mislead you. GI plus portion size tells the real story.

● Meanwhile... The Hack

Same grapes. One change.

The next day, I ate a cup of grapes alongside a small handful of almonds, at the same time, not after.

Protein and fat slow down digestion. When you eat them at the same time as the grapes, they slow the grapes down too.

Sixteen points saved. Almost half. And it took about ten seconds of effort.

● The Bigger Picture

So the candy nickname isn't crazy. Compared to actual candy, grapes are gentle.

But the moment you turn grapes into something else, that changes fast.

Dry a grape into a raisin and you concentrate the sugar into less food. Turn grapes into juice and you strip out the fiber that was slowing everything down. Build a fruit snack out of grape juice and food dye, and there's barely any actual fruit left in it.

The label keeps the word "grape." What's inside stops behaving like one.

This is the same trick behind a lot of foods marketed to parents and to anyone trying to eat well. Real fruit gets mentioned on the front of the package. The fiber that made the fruit gentle on your blood sugar gets left out of the ingredients. So you end up paying for the marketing of a fruit, without getting the actual fruit that made it safe to eat in the first place.

My daughter wasn't wrong, exactly. Grapes are sweet, and they're not hiding it.

But nature's candy earns that name by staying close to real food. Whole, with the fiber and water still attached.

I don't think that means eat grapes without a second thought. It just means the nickname holds up better than most health-food marketing does. That's rare enough to be worth noticing.

Eat a reasonable handful. Add something to slow it down if you want backup... and skip the juice.

Tomorrow, I'll show you the freezer trick that changes the whole texture of a grape, and whether it changes the spike too.

Stay steady