What the monitor taught me in three days

My sister wrote back.

She is the one who took fruit off the table at home. She read Wednesday's issue, saw that a cup of grapes raised my blood sugar more than a banana did, and took it as proof she had been right all along.

That is the opposite of what I meant.

So let me use the first Friday to put the week back together, and then answer her properly.

Three days in, here is everything the monitor showed.

The scoreboard

🍇 Grapes, 1 cup

+66

1.4 g fiber · the least of the three

🍌 Banana, on its own

+52

the one everybody expected to win

🍌🥜 Banana + peanut butter

+34

more carbohydrate than the banana alone, smaller rise

🍎 Apple, 1 medium

+31

3.8 g fiber · the quietest thing I ate all week

All four carried roughly the same carbohydrate. These are one person's readings and not medical advice. Everyone's body responds differently.

This week's rules

1. Count the fiber, not the fruit.
The apple and the grapes carried the same sugar. The apple brought almost three times the fiber, and raised my blood sugar less than half as much.

2. Use a bowl.
Grapes are the only thing I tested that you eat without deciding to. A bowl makes you choose the portion once, at the start.

3. Put fat or protein in front of the carb.
Two tablespoons of peanut butter added carbohydrate to my breakfast and still cut the rise by a third. Eat it first, not spread on top.

4. Buy bananas a little green.
A banana sits between 47 and 53 on the glycemic index. Spotty, it climbs to 57, because ripening turns some of its starch into sugar.

The question

Asked

So do I have to give up fruit, or not?

No. And the evidence on this is better than the evidence behind most things I will tell you.

Australian researchers followed 7,675 adults and published the results in the Journal of Clinical Endocrinology and Metabolism. They sorted people by how much fruit they ate.

The group eating about 230 grams a day, call it two pieces, had 36 percent lower odds of developing diabetes five years on than the group eating almost none.

Two details I am not going to skip over.

The first is that the group eating the most fruit of all did not do better than the group eating two pieces. More was not better. It was just more.

The second is that by twelve years, the difference was no longer statistically solid. This is one study watching what people chose to eat, not an experiment, so it shows a pattern rather than a cause.

One more thing from the same study. Fruit juice showed none of it.

Whole fruit was linked to better insulin sensitivity. Juice was not linked to anything.

So here is what I wrote back to my sister.

The chart on Wednesday was not an argument against fruit. It was an argument against assuming that two things in the same aisle do the same thing to you.

"Nobody in that study got healthier by eating less fruit. They got healthier by eating fruit instead of the thing it replaced."

Her kids can have the apple.

Next week: the diet drinks aisle

🔬

Mon

Coke Zero on the monitor

🛠

Tue

What to drink when you want a soda

🧠

Wed

Coke Zero vs Diet Coke vs sparkling

🔄

Thu

Regular Coke vs Coke Zero

Monday I drink a Coke Zero on an empty stomach and watch what happens. I have an opinion about what it will do. I have been wrong twice this week already.

If something this week surprised you, or you want a food put on the monitor, reply to this email. I read them, and Friday is where they end up.

— Stay steady

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

Browse every issue

One food. One monitor. One honest chart.