5

votes

Why the difference in responses to sugar in frozen fruit versus raw fruit?

Answered on August 19, 2014
Created August 10, 2011 at 7:33 PM

I've noticed that if I eat a few handfuls of fresh grapes, I get a headache, upper muscle tension, and a feeling of anxiety. This seems pretty consistent with the response I have to the same amount of any type of sugar that's not consumed with fat or protein. But I've noticed that if I consume frozen grapes in the same amount, I don't have any response. What causes this difference? Is it a matter of when in digestion the sugar from the fruit enters the blood stream? I.e. the frozen grapes take longer to digest and the further digestive point at which they do digest results in a smaller external reaction? Is it a matter of how much sugar the mouth perceives? I.e. is the mouth perhaps sending signals to brain to say that sweet = stress response? The frozen grapes don't taste sweet to me at all, but the fresh grapes taste very sweet.

(For background, I never had this type of reaction to sugar before going Paleo. It's only now that I eat fruit very rarely that I've become so sensitive to sugar. I'm fine with forgoing fruit, but I'm still curious about what's happening.)

226b10cbb6b1d3530b00d2d84a2dc86e

(3313)

on August 19, 2011
at 12:15 AM

Thanks Kaz. There may also be another variable. I know when I eat frozen fruit it makes my teeth hurt like ice cream does. I get freezer chills so I need a glass of water to wash it down. Who can eat frozen fruit without extra H2O? It's tough. So maybe the OP is drinking H2O with the frozen fruit and not thinking about it.

74f5d2ff6567edd456d31dfb9b92af61

(5227)

on August 18, 2011
at 11:35 PM

Sugar is hydrophilic. Once placed in the freezer, it'll attract the moisture in the air and actually gain weight due to absorption of water molecules. I think that because grapes are so high in sugar, they're probably sucking moisture out of the air and causing the water balance in the fruit to shift. I've done experiments testing it, and yes, frozen fruit weighs more than it's thawed counterpart. (Weighed both before and after freezing, of course.) I think BAMBAM's hypothesis is spot on.

226b10cbb6b1d3530b00d2d84a2dc86e

(3313)

on August 13, 2011
at 10:32 PM

@Danielle. I'm at an accredited college and will finish my Dietetic Internship through some hospital partnered with my college. I wish I had done community college for one semester because it's cheaper but beyond that I'd need courses not offered at community college. I'm eyeballing the MS in Nutrition Education at Columbia University. I want to be an RD, CDE before I even apply so I will work 2 years in the field after this for the CDE. Plus I have a teaching license so my credentials will match well with the Nutrition Education MS at Columbia. I've heard great things about Bastyr!

Cab7e4ef73c5d7d7a77e1c3d7f5773a1

(7314)

on August 13, 2011
at 10:20 PM

That would make sense actually because cold dampens taste. You always have to salt a cold soup more than a hot one.

65430e39d7e9e9322718d016fe668051

(2944)

on August 13, 2011
at 09:32 PM

You mentioned you are doing pre-reqs at a community college if I remember correctly? I've decided to go back to school and go that route too, and transfer to Bastyr University for holistic nutrition (the only regionally accredited school with a holistic health approach). Do you know where you want to transfer to after?

226b10cbb6b1d3530b00d2d84a2dc86e

(3313)

on August 13, 2011
at 09:10 PM

*blushing* thanx Danielle...my science talk never fails to get me weird looks at school here so that's a nice compliment.

65430e39d7e9e9322718d016fe668051

(2944)

on August 13, 2011
at 09:03 PM

BAMBAM, your science talk never fails to make my heart go BAMBAM

E46d4f7e35e46ee4e8211ab4bc852023

(1510)

on August 13, 2011
at 08:51 PM

Thanks mari, I definitely have considered this. It would totally make sense if I had the same response to all kinds of grapes, since I do sometimes feel guilt from eating sugar. But that still, for me, doesn't explain the difference between the frozen and fresh grapes. However, I wonder if it could be a sugary mouthfeel that triggers the psychosomatic reaction.

E46d4f7e35e46ee4e8211ab4bc852023

(1510)

on August 13, 2011
at 08:40 PM

Yes, I did freeze the grapes myself, after rinsing them. The rinsing might add some water, but not much.

559aa134ff5e6c8bcd608ba8dc505628

(3631)

on August 13, 2011
at 07:55 PM

hm. i dunno about that. anyway i assumed she was talking about grapes she froze herself. i could be wrong, i've just never seen store-bought frozen grapes.

226b10cbb6b1d3530b00d2d84a2dc86e

(3313)

on August 13, 2011
at 07:44 PM

Grenadine, they soak frozen foods in water to increase their weight and sale price.

E46d4f7e35e46ee4e8211ab4bc852023

(1510)

on August 13, 2011
at 07:27 PM

Thanks BAMBAM, I never would have considered this. I'll try your test out tonight!

559aa134ff5e6c8bcd608ba8dc505628

(3631)

on August 13, 2011
at 07:25 PM

"The frozen food contains a much higher level of H2O." Really?? How does sticking grapes in the freezer increase the water content?

E46d4f7e35e46ee4e8211ab4bc852023

(1510)

on August 13, 2011
at 07:25 PM

@grenadine, interest theory. I'll definitely consider it, since I am sensitive to yeast too.

6426d61a13689f8f651164b10f121d64

(11488)

on August 13, 2011
at 06:38 PM

@Olga, I don't know the answer, but props to you for offering such a huge bounty

559aa134ff5e6c8bcd608ba8dc505628

(3631)

on August 13, 2011
at 06:25 PM

does it happen with other fruit or just grapes? fresh grapes have live yeasts on them, which freezing probably makes dormant. (i'm "allergic" to yeast, so of course i see everything through a yeast- lens... sorry if it's a lame idea. p.s. i react about the same way to more than a couple of fresh grapes, plus worse).

D10ca8d11301c2f4993ac2279ce4b930

(5242)

on August 13, 2011
at 05:57 PM

I have the reverse problem. Frozen fruit speeds my digestion so as to make the end product "sloppy."

D10ca8d11301c2f4993ac2279ce4b930

(5242)

on August 13, 2011
at 05:55 PM

Are you eating the fruit thawed?

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5 Answers

best answer

3
34b560c8b9ce660d7839fb7e29d7be89

on August 14, 2011
at 08:07 AM

I think that the temperature plays a role in this case. "The temperature dependence of the taste intensity is especially pronounced in the case of D-fructose" (Food Chemistry, p. 259 can be found on books.google.com). Now this next part is a stretch but there seems to be some psychosomatic mechanism capable of triggering physiologic responses to perception of sweetness. From The British Journal of Nutrition; "...the sweeter that a volunteer percieved a given drink to be, the less his hunger was surpressed by consumption of that drink." So seeing as how you observed similar responses to similar amounts of sugar in other forms (not frozen) and also noted that the frozen grapes were not as sweet, I would think that it is indeed the perception of sweetness, which is lower with colder temperatures, that is responsible for the difference in your body's response.

links to sources:

http://books.google.com/books?id=xteiARU46SQC&lpg=PA259&ots=HzFqbJWRsA&dq=sweetness%20dependent%20on%20temperature&pg=PA259#v=onepage&q=sweetness%20dependent%20on%20temperature&f=false

http://arno.unimaas.nl/show.cgi?fid=2033

3
7bf306ada57db47547e9da39a415edf6

(11214)

on August 18, 2011
at 06:38 PM

My guess is histamines. Freezing grapes must destroy, make dormant, or minimize whatever is causing the allergic reaction to the fresh ones.

I first noticed this effect when I was a child. Fruit was supposed to be good for you, but trying to just fill up on fruit tended to make my head hurt and I'd feel a bit like I had hayfever. I've also had histamine responses to exercise when I was younger. I have been eating frozen fruit this summer and I haven't noticed a reaction at all.

wikipedia's Histamine page

Since the sugar is the same in both cases, the logical thing to do is look for some other factor.

3
226b10cbb6b1d3530b00d2d84a2dc86e

(3313)

on August 13, 2011
at 06:41 PM

The sugar content is fixed between your frozen vs. fresh fruits, right? The only variables you have here are 1)temperature and 2)something maybe less obvious on the surface. One food is cold and the other is room temperature. The second and more elusive variable is water content. The frozen food contains a much higher level of H2O.

Let's ignore temperature and focus on the H2O variable. Water happens to be a byproduct of glycolysis, or the breakdown of glucose (C6H12O6) to make ATP. The primary waste byproduct of cellular respiration is CO2.

This YouTube explains cellular respiration (Glycolysis, Kreb's Cycle, Oxidative Phosphorylation):

Click here to watch a cell break down sugar

When you convert sugar/glucose (C6H12O6) to make ATP + CO2 + H2O you want your cells to be fully hydrated or balanced with H2O. At worst, if you do not have enough H2O to balance out the CO2, your body will attempt to acquire more O2 and you will hyperventilate (breathe in too much O2 and get rid of too much CO2 too quickly). Your body is just trying to balance PH because excess CO2 makes the blood more acidic.

Can H2O help buffer the blood? Of course. You can use the oxygen atoms from H2O molecules.

Blood PH

Excess CO2 may be causing the symptoms you describe. I suspect your level of dehydration factors into your body's differing responses to consumption of glucose in fresh fruit vs. glucose consumption in the form of frozen fruit with higher H2O content.

In your daily life, it's possible that you do not drink enough H2O, drink too much caffeine or both.

Headache, muscle cramps and panic attacks/anxiety are all conditions present where there is an excess of CO2 and lack of adequate water buffer to balance blood PH.

To test my hypothesis, try drinking a glass of distilled H2O 1 hr prior to consuming the glucose in fresh fruits. Bump up to 2 glasses of H2O, 30 minutes before eating fresh fruits. If the extra hydration has no effect on your symptoms then I am wrong (probably the case because I'm still studying basic science courses). If hydration does reduce symptoms, then H2O is at play here and I win the bounty!!!!

Maybe you don't have to say goodbye to fruit? Maybe you just need to say hello to more H2O?

226b10cbb6b1d3530b00d2d84a2dc86e

(3313)

on August 13, 2011
at 09:10 PM

*blushing* thanx Danielle...my science talk never fails to get me weird looks at school here so that's a nice compliment.

65430e39d7e9e9322718d016fe668051

(2944)

on August 13, 2011
at 09:32 PM

You mentioned you are doing pre-reqs at a community college if I remember correctly? I've decided to go back to school and go that route too, and transfer to Bastyr University for holistic nutrition (the only regionally accredited school with a holistic health approach). Do you know where you want to transfer to after?

E46d4f7e35e46ee4e8211ab4bc852023

(1510)

on August 13, 2011
at 08:40 PM

Yes, I did freeze the grapes myself, after rinsing them. The rinsing might add some water, but not much.

226b10cbb6b1d3530b00d2d84a2dc86e

(3313)

on August 13, 2011
at 10:32 PM

@Danielle. I'm at an accredited college and will finish my Dietetic Internship through some hospital partnered with my college. I wish I had done community college for one semester because it's cheaper but beyond that I'd need courses not offered at community college. I'm eyeballing the MS in Nutrition Education at Columbia University. I want to be an RD, CDE before I even apply so I will work 2 years in the field after this for the CDE. Plus I have a teaching license so my credentials will match well with the Nutrition Education MS at Columbia. I've heard great things about Bastyr!

226b10cbb6b1d3530b00d2d84a2dc86e

(3313)

on August 13, 2011
at 07:44 PM

Grenadine, they soak frozen foods in water to increase their weight and sale price.

559aa134ff5e6c8bcd608ba8dc505628

(3631)

on August 13, 2011
at 07:25 PM

"The frozen food contains a much higher level of H2O." Really?? How does sticking grapes in the freezer increase the water content?

559aa134ff5e6c8bcd608ba8dc505628

(3631)

on August 13, 2011
at 07:55 PM

hm. i dunno about that. anyway i assumed she was talking about grapes she froze herself. i could be wrong, i've just never seen store-bought frozen grapes.

65430e39d7e9e9322718d016fe668051

(2944)

on August 13, 2011
at 09:03 PM

BAMBAM, your science talk never fails to make my heart go BAMBAM

E46d4f7e35e46ee4e8211ab4bc852023

(1510)

on August 13, 2011
at 07:27 PM

Thanks BAMBAM, I never would have considered this. I'll try your test out tonight!

74f5d2ff6567edd456d31dfb9b92af61

(5227)

on August 18, 2011
at 11:35 PM

Sugar is hydrophilic. Once placed in the freezer, it'll attract the moisture in the air and actually gain weight due to absorption of water molecules. I think that because grapes are so high in sugar, they're probably sucking moisture out of the air and causing the water balance in the fruit to shift. I've done experiments testing it, and yes, frozen fruit weighs more than it's thawed counterpart. (Weighed both before and after freezing, of course.) I think BAMBAM's hypothesis is spot on.

226b10cbb6b1d3530b00d2d84a2dc86e

(3313)

on August 19, 2011
at 12:15 AM

Thanks Kaz. There may also be another variable. I know when I eat frozen fruit it makes my teeth hurt like ice cream does. I get freezer chills so I need a glass of water to wash it down. Who can eat frozen fruit without extra H2O? It's tough. So maybe the OP is drinking H2O with the frozen fruit and not thinking about it.

2
Cab7e4ef73c5d7d7a77e1c3d7f5773a1

(7314)

on August 13, 2011
at 07:35 PM

Since you noted it didn't happen before paleo, is there a chance its a psychosomatic reaction? I think our minds play a huge role in how we react to foods. If I have some sugar but I'm completely ok with it and enjoy it, I won't really feel much worse. If, however, I regret it, then there's a good chance I'll notice some unwanted effects. I also remember Kurt Harris talking about one patient of his who convinced herself she could eat only chicken breast and oatmeal (or something like that). Anyway, just something to consider.

Cab7e4ef73c5d7d7a77e1c3d7f5773a1

(7314)

on August 13, 2011
at 10:20 PM

That would make sense actually because cold dampens taste. You always have to salt a cold soup more than a hot one.

E46d4f7e35e46ee4e8211ab4bc852023

(1510)

on August 13, 2011
at 08:51 PM

Thanks mari, I definitely have considered this. It would totally make sense if I had the same response to all kinds of grapes, since I do sometimes feel guilt from eating sugar. But that still, for me, doesn't explain the difference between the frozen and fresh grapes. However, I wonder if it could be a sugary mouthfeel that triggers the psychosomatic reaction.

0
Medium avatar

(10611)

on August 14, 2011
at 12:53 PM

I wonder if freezing shifts glycemic index and changes digestibility. I dredged glycemicindex.com for a comparison between fresh grapes and frozen grape juice, but found nothing. However oranges are well covered. It looks like going from fresh fruit to frozen juice increases the index by about 20%. I'd postulate rupturing/removing the juice sacs aids digestibility. The sugar is thus more accessible after freezing. In the bad sense freezing causes more of a blood sugar spike, but in the good sense it passes through digestion faster.

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