Freezing bread affecting carbs

[CliffH]

I took a pack of cooked meat, two slices of fresh bread, three of ham, weighed the butter and pickle, and the finished sandwich after adding lettuce. Put the loaf in the freezer meat in the fridge. Ate the sandwich, checked blood glucose levels as normal.
Next day I took the bread from the freezer, let it warm up, did the same thing checking that the parts and whole sandwich weighed the same.
Result - total sameness.
A few weeks later I did the same again, on the same day of the week, with the same results.
Having a scientific background I'm pretty sure that if there was any benefit to be gained by freezing high carb foods, I'd have seen it.

I too have a scientific background and I admire your rigour! Can I be a co-author on your paper? 😉.

 

[Drummer]

I too have a scientific background and I admire your rigour! Can I be a co-author on your paper? 😉.

I think that something needs to be done to break the wall of misinformation people hit straight after diagnosis - but getting people to join up here would be a good start.

 

[saz9961]

The idea is that when when frozen, or even chilled, the starch crystalises (and some papers indicate glucose can promote this), in the same way as cooked potatoes, pasta and rice are similarly affected. The process is irreversible, hance the foods can be warmed up.

Starch in bread is broken down by amylase in saliva and maltase in the small intestine to glucose.

Resistant starch though cannot be hydrolysed by these enzymes, and so is broken down in the large intestine. However, this time, its fermented by bacteria to acetyl CoA.

A bit of O-Level biology as a reminder

Some have looked at this phenomenom from the perspective of reducing colorectal cancer.

The impact of freezing and toasting on the glycaemic response of white bread - PubMed

All three procedures investigated, freezing and defrosting, toasting from fresh, and toasting following freezing and defrosting, favourably altered the glucose response of the breads. This is the first study known to the authors to show reductions in glycaemic response as a result of changes in...

pubmed.ncbi.nlm.nih.gov

Freezing bread could reduce the glycaemic response by almost 31%. All the media reports, TikToks etc are based on this 2008 paper. The paper reports an effect, in a small group. The supposition is that the change is due to the development of RS4. But likely, most of the starch just stays as starch. The study was made using homemade bread, so the effect might be different with commercial batches.

There are more studies looking at potatoes and rice. In potatoes, the RS4 content is increased by 50% when a cooked potato is chilled. What that means is a shift in resistant starch content from about 3% of the potato to 6%.

I don't think the change is all that significant for how you eat food now. Its more significant in the context of increasing the RS content in uncooked foodstuffs.

 

[CliffH]

I took a pack of cooked meat, two slices of fresh bread, three of ham, weighed the butter and pickle, and the finished sandwich after adding lettuce. Put the loaf in the freezer meat in the fridge. Ate the sandwich, checked blood glucose levels as normal.
Next day I took the bread from the freezer, let it warm up, did the same thing checking that the parts and whole sandwich weighed the same.
Result - total sameness.
A few weeks later I did the same again, on the same day of the week, with the same results.
Having a scientific background I'm pretty sure that if there was any benefit to be gained by freezing high carb foods, I'd have seen it.

I think that something needs to be done to break the wall of misinformation people hit straight after diagnosis - but getting people to join up here would be a good start.

I think that something needs to be done to break the wall of misinformation people hit straight after diagnosis - but getting people to join up here would be a good start.

If I'd been aware of this forum when I was diagnosed I'd have learnt lots of useful stuff - but how would I have sorted the wheat from the chaff? Even with my scientific background, sometimes I lose the will to live when I read long posts full of dense data and references to obscure studies.

 

[CliffH]

The idea is that when when frozen, or even chilled, the starch crystalises (and some papers indicate glucose can promote this), in the same way as cooked potatoes, pasta and rice are similarly affected. The process is irreversible, hance the foods can be warmed up.

Starch in bread is broken down by amylase in saliva and maltase in the small intestine to glucose.

Resistant starch though cannot be hydrolysed by these enzymes, and so is broken down in the large intestine. However, this time, its fermented by bacteria to acetyl CoA.

A bit of O-Level biology as a reminder

Some have looked at this phenomenom from the perspective of reducing colorectal cancer.

The impact of freezing and toasting on the glycaemic response of white bread - PubMed

All three procedures investigated, freezing and defrosting, toasting from fresh, and toasting following freezing and defrosting, favourably altered the glucose response of the breads. This is the first study known to the authors to show reductions in glycaemic response as a result of changes in...

pubmed.ncbi.nlm.nih.gov

Freezing bread could reduce the glycaemic response by almost 31%. All the media reports, TikToks etc are based on this 2008 paper. The paper reports an effect, in a small group. The supposition is that the change is due to the development of RS4. But likely, most of the starch just stays as starch. The study was made using homemade bread, so the effect might be different with commercial batches.

There are more studies looking at potatoes and rice. In potatoes, the RS4 content is increased by 50% when a cooked potato is chilled. What that means is a shift in resistant starch content from about 3% of the potato to 6%.

I don't think the change is all that significant for how you eat food now. Its more significant in the context of increasing the RS content in uncooked foodstuffs.

This explains why I only got a 'B' at Biology O-Level .

 

[Drummer]

As far as I can see - if there is no difference in my blood glucose levels, what is the point?
I don't see any difference in low and high GI and GL foods either, the only thing which causes a change is less carbohydrate in my diet.

 

[saz9961]

This explains why I only got a 'B' at Biology O-Level .

I have an unfair advantage. PhD Microbiology.

 

[CliffH]

I have an unfair advantage. PhD Microbiology.

I have an unfair advantage. PhD Microbiology.

I feel like I could probably get a PhD in bread after reading these posts

 

[Docb]

I have an unfair advantage. PhD Microbiology.

That's good, so maybe you could clear up a couple of things for me.

What is that diagram, the one you posted above, about. I also have a PhD and am quite good at diagrams but I cannot see what that one is about. Which bit is about processing carbohydrate in the gut?

Am I right in my assumption that the more complex carbohydrates are those which are more "resistant" to digestion? If so, am I being misled by my basic instincts, that freezing things will tend to break down structures rather than making them more complex? If freezing has any effect would you not expect it to reduce the amount of complex carbohydrate?

Are you suggesting that this whole thing is based on a single document without any confirmation from other work? If so, why are we discussing the topic?

 

[Martin.A]

Can I just point out that DUK has a section promoting this and if the general opinion of members is that it's spurious, as seems to be the case, then maybe DUK should consider removing it.

Mike? @everydayupsanddowns

 

[saz9961]

That's good, so maybe you could clear up a couple of things for me.

What is that diagram, the one you posted above, about. I also have a PhD and am quite good at diagrams but I cannot see what that one is about. Which bit is about processing carbohydrate in the gut?

Am I right in my assumption that the more complex carbohydrates are those which are more "resistant" to digestion? If so, am I being misled by my basic instincts, that freezing things will tend to break down structures rather than making them more complex? If freezing has any effect would you not expect it to reduce the amount of complex carbohydrate?
biota
Are you suggesting that this whole thing is based on a single document without any confirmation from other work? If so, why are we discussing the topic?

1. The diagram is for those unfamiliar with Acetyl CoA and the Krebs Cycle. Fundamentally, the starch does not end up as glucose. The excess Acetyl-CoA is used by muscle cells. Insulin has many functions, eg regulation of glucose uptake by cells, but it also modulates Acetyle CoA Carboxylase (increases activity).

2. I am only discussing starch, not carbohydrates in general. I sould correct myself; chilling and freezing of starch results in generation of RS3 (not RS4) through retrogradation. We can't really eat starch (trying eating a raw potato). Cooking breaks down the starch crystal into a viscous form (starch is of course amylose, amylopectin). That allows our amylase and maltase to start breaking it down to glucose. As the food cools, the crystalline structure tries to realign (ie. cold rice sitting out on the top is not the same as that fluffy fresh booked stuff, its changed). Chilling and freezing come into it because amylose crystallizes more quickly than amylopectin. In the cystalline form, the the bonds these enzymes hydrolyze are inaccessible, enzymology 101, lock-and-key hypothesis. You are indeed mislead. The bacterial fermentation can take a number of routes, depending on the bacterial biota. You're going to end up with Hexose, Pentose, Deoxy-hexose. Via the Pentose Phosphate pathway, these end up as Pyruvate, and thence of course Acetyle-CoA. There are a few different routes bacteria then ferment this to acetate, butyrate and propionate. Other bacteria can also take the Deoxy-hexose, to 1,2-Propanediol and then to Propionate. This is a significant process in nutritional science.

3. As I said, media reports and Tiktok highlighting this are referencing the Oxford-Brookes report. But there is other information in the literature. The 2008 paper is well cited (in 80 papers it seems). I suspect the work came out of observations that the quality of doughs changed when frozen.

4. I have no idea why this topic was started, Not a telepath.

My PhD was in marine microbial ecology, looking at particular methylotrophic enzymatic pathways, but most of my career has been in infectious diseases (everything). What area was your PhD?

 

[everydayupsanddowns]

Can I just point out that DUK has a section promoting this and if the general opinion of members is that it's spurious, as seems to be the case, then maybe DUK should consider removing it.

Mike? @everydayupsanddowns

The concept of cooking (or freezing), cooling, and reheating causing changes in some of the starches making them harder to access has been around for a few years, and there are a few peer-reviewed papers which investigate and explain the phenomenon.

But I think it’s certainly going to be another YDMV thing - this is diabetes after all!

My gut feeling is that I get slightly fewer problems these days with bread than I used to. Mostly my estimates and dose timings work, where I used to get occasional big spikes despite “doing everything right”. Coincidentally, during lockdown we started keeping spare bread in the freezer (in case we became confined to barracks), and I’ve continued to do that - so now all bread I eat has been frozen and defrosted.

So for me there is an apparent association between frozen/defrosted bread and reduced variability following bread-including meals (almost 2/3 of my diet).

It’s only a modest change, and may be an illusion. But it has encourages me to keep freezing and defrosting!

 

[Martin.A]

Would be interested to continue this conversation, but only on the proviso that you're comfortable with me not having to caveat and couch my questions, walk on eggshells etc. for fear of offending you or you getting the feeling I'm calling you dishonest. This is nothing personal. I just want us all to see if we can get a better understanding of this.

No obligation, either way.

Please note from Lucyr's signature that they're autistic and take this into account when responding.

 

[CliffH]

Could you perhaps explain to me where you see the rigour in this case?

Thanks!

I doubt that I can explain it to you. However, for me as a humble person without a PhD, the steps that Drummer outlined looked as rigorous as a Professor of Rigour winning a national 'Rigorous Research of the Year' competition.

 

[CliffH]

Perhaps you could give it a shot. And then I'll try to explain why I disagree 😉

Unfortunately, as Phil Spector said regarding Paul McCartney's anger at him overdubbing strings onto 'The Long and Winding Road', I think you've got me "mixed up with someone who gives a ****". As Lucyr says above, "It's only a sandwich".

 

[everydayupsanddowns]

looked as rigorous as a Professor of Rigour winning a national 'Rigorous Research of the Year' competition.

Are you a fan of Blackadder @CliffH

 

[everydayupsanddowns]

It's the cantankerousness, right? 😉

More the similarities to some of Blackadder’s infamous similes

“He’s mad. He’s madder than Mad Jack McMad, winner of last years Mr Madman competition”

“as cunning as a fox, who has just been appointed Professor of Cunning at Oxford University?”

etc

 

[CliffH]

Are you a fan of Blackadder @CliffH

What makes you ask that?

 

[CliffH]

It's the cantankerousness, right? 😉

I'm only cantankerous when I eat bread that's been frozen

 

[everydayupsanddowns]

What makes you ask that?

View attachment 32357

I think you look like a bird who’s swallowed a plate.