Real CGM data from 2,394 members

Does a banana spike your blood sugar?

We looked at Vively members who ate a banana on its own while wearing a glucose sensor. Here is what happened, how it compares, and how to find out what it does to you.

A ripe banana
+1.6mmol/L
typical rise after a banana on its own
01234 mmol/L

Half of members rose between 0.9 and 2.2 mmol/L.

Peak at about 30 minBack near baseline in about 90 min

Short answer: Banana raised blood sugar by a typical 1.6 mmol/L in 2,394 Vively members who wore a continuous glucose monitor (CGM) and logged it on its own. The middle half of members rose between 0.9 and 2.2 mmol/L. Banana is the most-logged food in our data, and pairing it with peanut butter, yoghurt or nuts brought the typical rise down.

The basics

Why a glucose spike matters

When you eat carbohydrate, your body breaks it down into glucose and your blood glucose rises. That is normal, because glucose is your body’s main fuel. Insulin then moves it out of your blood and into your cells, and your level comes back down.

You eatUsual levelPeak The risepeak minus yourusual level Back to baseline
How to read a glucose curve (illustration). The rise is the number we show for every food.

How you feel a few hours later

A big rise is sometimes followed by a dip below where you started. In a study of 1,070 people, those with bigger dips after breakfast felt hungrier sooner and ate more over the rest of the day.

How hard your insulin works

Bigger, more frequent rises mean your body releases more insulin. If your cells stop responding well to it (insulin resistance), your body has to make even more. Insulin resistance usually builds for 10 to 15 years before a standard glucose blood test picks it up.

Your long-term health

Studies of people without diabetes have linked higher glucose levels, including two hours after a sugary drink, with a higher risk of heart disease. Higher rises after meals are also often one of the first changes on the way to type 2 diabetes.

One rise is not a problem

Glucose is meant to go up after you eat. What matters is your pattern over weeks: how high you go, how often, and how quickly you come back down. That pattern is personal, so measuring it beats guessing.

If you have diabetes or take medicine that lowers glucose, talk to your doctor before changing how you eat.

The pairing test

Same banana, smaller curve

173 members in the Sydney and Melbourne time zones logged a banana both ways: on its own, and with peanut butter, yoghurt, nuts or another protein or fat food. These are their average curves. Drag across a chart to read it. The 389 figure below counts members in every time zone.

A ripe banana

Banana on its own

173 members
A ripe bananaA teaspoon of smooth peanut butterA small bowl of plain Greek yoghurt

With protein or fat

Same 173 members
19%

lower average peak with a pairing

21%

less glucose under the curve over 2 hours

56%

of 389 members across Australia rose less when they paired it

Average curves look gentler than any one person’s, because people peak at different times. Looking at each member’s typical rise instead, it fell from 1.5 mmol/L on its own to 1.2 with a pairing.

44% saw no benefit. For them, the pairing made no difference or a bigger rise. Which group are you in?

Test it on yourself
Everyone is different

Ten people, ten different bananas

Line up 2,394 members from smallest to biggest typical rise after a banana, then pick ten people evenly spaced along the line. Same food, very different curves.

+0.2
Person 1
+0.2
Person 2
+0.9
Person 3
+1.2
Person 4
+1.4
Person 5
+1.7
Person 6
+1.9
Person 7
+2.2
Person 8
+2.7
Person 9
+3.7
Person 10
30%

barely moved, with a typical rise under 1.0 mmol/L

18%

rose 2.5 mmol/L or more

Why banana raises your glucose

A banana's carbohydrate changes as it ripens. Green bananas have more resistant starch, which digests slowly. As they ripen, that starch turns into sugar, so a spotty banana tends to raise glucose more than a firm one. Members' curves peaked around 30 minutes after eating and were back near baseline within about an hour and a half.

With 2,394 members, this is our biggest group, and the spread is wide.

Portion size, what you ate earlier, sleep, stress, movement and your menstrual cycle all change the curve too. That is why we built Vively around testing your own meals instead of handing out food lists.

Play

Guess the spike

Five quick rounds using our members’ data. How well do you know your banana?

How it compares

Where banana sits among 20 everyday foods

Typical rise in mmol/L when each food was eaten on its own. Every food has at least 30 members behind it. Tap a food to see its page.

See all 38 foods on our glucose spikes page.

Your turn

Three banana experiments to run on yourself

Averages only get you so far. These are the tests our members run with their sensors.

Members’ result

Plain vs paired

Eat a banana on its own one day, and with peanut butter or Greek yoghurt the next. In 389 members, 56% rose less with the pairing.

Try it

Firm vs spotty

As a banana ripens, slowly digested starch turns into sugar. Try a firm one and a spotty one on different days and compare your peaks.

Try it

Sit vs walk

After the same meal, sit one day and take a 10-minute walk the next. Compare how high you go.

Your banana curve is yours alone

Wear a CGM with Vively and see the rise, the peak and the recovery for every meal you log. Then try a swap and compare the two curves side by side.

Get your CGM
Vively app meal screen showing a glucose curve next to a swap from the week before

Questions about banana and blood sugar

Does a banana spike blood sugar?

A little, for most people. 2,394 Vively members wearing a CGM rose a typical 1.6 mmol/L after a banana on its own, and their glucose was back near baseline within about 90 minutes. The middle half rose between 0.9 and 2.2 mmol/L.

Does peanut butter with a banana lower the spike?

In our data, pairing helped. 389 members logged bananas both on their own and with protein or fat foods like peanut butter, yoghurt or nuts. Their typical rise fell from 1.5 to 1.2 mmol/L, and 56% rose less when they paired it.

Do riper bananas raise blood sugar more?

Usually, yes. As a banana ripens, its resistant starch turns into sugar, which is absorbed faster. Our members don't log ripeness, so this is one to test yourself.

What is a normal rise after eating?

There is no official cut-off for a spike in people without diabetes. In a 2019 study of healthy adults who wore CGMs, glucose stayed between 3.9 and 7.8 mmol/L for about 96% of the day. Rises after meals are normal. How high you go, how long you stay there and your pattern over weeks matter more.

How did you get these numbers?

We used meals logged in the Vively app by members wearing a CGM between January 2022 and October 2026, leaving out members who told us they have type 2 diabetes, and our own staff. The rise is the highest reading in the two hours after eating, minus the member’s average for the four hours before. If glucose fell, we counted the rise as zero. We took each member’s own median first, then the median across members. “On its own” means the food was the only item logged for that meal. The curves use members in the Sydney and Melbourne time zones, meals since January 2023 and each member’s three most recent meals of each kind. Data is de-identified and only shown when at least 30 members contribute. This is observational app data, not a controlled GI test, and portions vary.

More from Vively

Sources

  1. Vively member CGM data, de-identified and aggregated, pulled 12 and 13 October 2026.
  2. Shah VN et al. Continuous glucose monitoring profiles in healthy nondiabetic participants: a multicenter prospective study. Journal of Clinical Endocrinology and Metabolism, 2019.
  3. Wyatt P et al. Postprandial glycaemic dips predict appetite and energy intake in healthy individuals. Nature Metabolism, 2021.
  4. Levitan EB et al. Is nondiabetic hyperglycemia a risk factor for cardiovascular disease? A meta-analysis of prospective studies. Archives of Internal Medicine, 2004.
  5. Ceriello A et al. Guideline for management of postmeal glucose. Nutrition, Metabolism and Cardiovascular Diseases, 2008.

This is observational data from real meals, not medical advice.