Confused by grapes ( and more)

[MrsA2]

For probably about 15 years now I have carefully tended a white grape vine growing on the side of my garage here in South East UK and finally it had started to produced edible fruit. I am even learning how to beat the wildlife to the harvest!!!!
So I am sure you'll understand how sorry I was to think that I'd never eat my own grapes again now that I have been diagnosed T2 and every list has grapes as one of carbiest of fruits. I did sneak a handful the other day while gardening and didn't test for them so I thought I'd do it all properly and set up an experiment
So today I had an otherwise very low carb lunch of cheese, olives and finished with just 30g of my home grown grapes and 1 single bought grape as a taste comparison. Mine were much sweeter and tastier and were seeded, although I didn't eat the seeds.
First bite test was 6.7 (had just done an hours moderate exercise class)
2 hours later was 6.4 !!!!!
Not all what I expected, so what is going on here? Is there something in the few seconds and few yards between picking and eating, or are the commercial grapes pumped full of stuff and get carbier the further they travel perhaps?
I attach a picture showing 26g of my grapes and 50g of commercial, the latter are fewer in number but I am assuming these are the sort used for measuring carbs on sites like diet doctor that give 16g carbs per 100g

Suppose what I am asking is how to know when to believe a carb will raise my bg and when it won't. Are some carbs worse than others?
Would I get the same results another day?
I am so confused

 

[KK123]

First bite test was 6.7 (had just done an hours moderate exercise class

Hi there, all I would say is that when you are doing a carb experiment it's always best to do it on as normal a day as possible by which I mean NOT after an hours moderate exercise, or a walk to the shops or a row with your neighbour, etc. The carb content is obviously the most important factor when testing to see how various foods affect you but to use this as an example, if I do an hours exercise before eating 30g of carbs I do not need ANY insulin for it and for many hours after, if I have been sat watching Netflix for hours before those very same carbs then I DO need to take insulin for it. It may be that your hours exercise has contributed to lower the impact of those grapes. Maybe you could try it again but without the exercise when you are comfy & calm? xxx

 

[Antje77]

I would suspect a quick, short spike from grapes, about the same as sweets. They work fine for a hypo treatment for me, but I often need some slower acting carbs afterwards to prevent dropping again.
Can it be you missed the spike and dropped back to normal within those 2 hours?

 

[Brunneria]

I think your test at 2 hours may have completely missed any raise from the grapes, although the rate the grape sugars would arrive (and disappear) in the bloodstream is going to depend heavily on the content and portion size of the food it was eaten with.

Although for me, the exercise would probably have been the biggest factor, and fruit on an empty stomach seems to raise and then drop in less than an hour, so it wouldn’t ever show on a 2hr reading.

to get a ‘baseline’ i would probably eat the grapes mid-late afternoon, by themselves, on an empty stomach, while having a sedentary afternoon. And I would test every 10 mins to see what was going on.

 

[MrsA2]

Wow, thanks.
Another experiment will be on the way.
Any excuse to eat grapes!

 

[Rustytypin]

I did a similar experiment with one of my home grown apples a few days ago.
The apple weighed about 100 grams as eaten, so about 10-15 grams of carbs (half my usual daily total).
Bg before apple, 6.2; after 30 mins, 6.5; 60 mins, 6.5; 90 mins, 5.9; 150 mins, 5.4.
Later, after evening meal, 120 mins, bg was 5.6.
Normally if I have that amount of carbs in a meal, I can expect a rise of around 0.5 mmol so a bit baffled, although I am usually around 5.0 before my evening meal. So perhaps a slight rise to usual.
Maybe home grown is just better for you!

 

[DCUKMod]

One other comment I might make is, for me, fruit miles 9and other things) matter.

In the Tropics, as observed via Libre, I can eat mango or pineapple, sour sap, papaya, mangosteen or even finger bananas, but here my reactions are different.

When away, we are usually extremely active; whether sailing, walking cycling or whatever, and of course, I'm usually very relaxed, and for me, enjoying the hot weather.

So, whilst I joke about fruit miles, I feel certain it's a little more complex than that.

 

[KK123]

I did a similar experiment with one of my home grown apples a few days ago.
The apple weighed about 100 grams as eaten, so about 10-15 grams of carbs (half my usual daily total).
Bg before apple, 6.2; after 30 mins, 6.5; 60 mins, 6.5; 90 mins, 5.9; 150 mins, 5.4.
Later, after evening meal, 120 mins, bg was 5.6.
Normally if I have that amount of carbs in a meal, I can expect a rise of around 0.5 mmol so a bit baffled, although I am usually around 5.0 before my evening meal. So perhaps a slight rise to usual.
Maybe home grown is just better for you!

Hi there, the differences in your levels are minimal so I wonder whether it's more to do with the inability of the glucometer to record the exact reading (they are normally deemed to be 'accurate' even when a reading shows 1 to 1.5mmol off). I have tested on numerous meters, same fingers, same time and on and on and every time I take a reading it can be anything up to a 1 to 2mmol difference. Having said that you know your meter and its capabilities so it could just be that a 0.5 difference is hardly a difference, I can run up the stairs and it jumps 2 points and comes down just as quick. I wonder whether the mantra of '2 hours later it should be within 2m of the starting figure' is simply down to the known limitations of the device. x

 

[Rustytypin]

I am fairly confident that my meter is reasonably accurate, I often play “guess the reading” when I test. I am more often than not pretty close to the meter.
I have four meters and my go to one (contour next) has shown itself to be the most reliable. It does seem to read slightly higher than the others, but is more consistent, but yes, I do not treat its readings as gospel.

 

[MrsA2]

I think there is more to learn about seasonality and localness. Are there any actual studies out there anywhere?

 

[Antje77]

I think there is more to learn about seasonality and localness. Are there any actual studies out there anywhere?

I don't know about that, but the grapes growing outside my front door definitely get my bg up.

 

[Roggg]

To be fair, the serving size you are using is only about 8 grams of carb in total. 8g net carb is well under even a strict keto guideline, so if that's your only "cheat" from ultra-low carb eating, then it;'s unlikely to have much effect on your glucose if it's not a regular thing.

 

[Member496333]

Don’t forget the fructose, which won’t really raise blood glucose concentration but will incrementally increase insulin resistance.

 

[MrsA2]

Don’t forget the fructose, which won’t really raise blood glucose concentration but will incrementally increase insulin resistance.

I had forgotten about the evil fructose. Silly me

 

[MrsA2]

To be fair, the serving size you are using is only about 8 grams of carb in total. 8g net carb is well under even a strict keto guideline, so if that's your only "cheat" from ultra-low carb eating, then it;'s unlikely to have much effect on your glucose if it's not a regular thing.

I had forgotten total carbs. Silly me