7

votes

Does eating fat with starch decrease the digestibility of the starch?

Answered on September 12, 2014
Created July 20, 2011 at 5:29 PM

I just came across this comment from Don Matesz on his most recent blog post:

...I think that increasing starch while simultaneously still getting ~50% or more of calories from fat reduces the digestibility of the starch, resulting in larger amounts of starch making it to the large intestine for fermentation. Generally, 10-20 percent of starches go undigested anyway, but fats can coat starch molecules, making it difficult for starch-digesting enzymes to break down the starches in time for them to be absorbed...as a result, more undigested starch makes it to the colon than when starch is consumed with very little fat. In fact, this effect of fat on slowing starch digestion is one of the erroneous 'rationales' people give for always eating fats with starches.

Could this be the reason why the glycemic response is lower in a meal of potatoes and fat than in a meal of potatoes alone?

http://journals.cambridge.org/action/displayAbstract?fromPage=online&aid=8307865

Maybe the mechanism is not that the fat slows the absorption of the glucose in the small intestine, but that the fat "coats" the starch molecules and a larger percentage of them move through to the colon for fermentation, therefore reducing the total amount of glucose absorbed into the bloodstream? What impact could this have on indigestion and bacterial (over)growth?

Medium avatar

(10611)

on December 13, 2012
at 01:29 PM

I used to have 5 downvotes on this. Attitudes have changed here. The fat/starch combo encompasses almost every processed and comfort food. People are touchy about the fat part, but the fat is high calorie PUFA's. And now one of the biggest providers - Hostess - is gone. A good thing.

Medium avatar

(2417)

on December 12, 2012
at 08:57 AM

Why the down votes? He's 100 percent correct. Guess its a case of shoot the messenger when the message is something that conflicts with what folks desire. Fat plus starch at the same meal is the EASIEST way to get fat yourself, hands down, for myriad reasons.

Medium avatar

(10611)

on July 21, 2011
at 10:00 PM

I realize people here are not affected by the radioactivity of the fat/carb complex. But it's a prime cause of obesity in the world at large. I'm talking Snickers, pizza and donuts as regular diet; not an occasional croissant made with Kerrygold. But whether the fat is lard, trans or PUFA, I don't see any synergistic good combination. And a Jo-Jo is a wedge cut potato deep fat fried in mystery oil, covered with orange salty powder and served in a tray with ranch dressing. Overeating them made me obese.

531db50c958cf4d5605ee0c5ae8a57be

(8878)

on July 21, 2011
at 04:20 PM

Don't know what "jo-jos" are but my guess is you'll find few people on this site that eat donuts on a regular basis...

531db50c958cf4d5605ee0c5ae8a57be

(8878)

on July 21, 2011
at 04:18 PM

Good luck with that!

E48833ca4e98b24f35191a02e84cc262

on July 21, 2011
at 02:08 AM

Croissants...damn, hide the nutella quick....

Medium avatar

(10611)

on July 21, 2011
at 01:57 AM

Well downvote me all you like but stay away from the jo-jos and donuts on the next trip to the jiffy mart. Trans fat anyone?

76f3ead3aa977d876bcf3331d35a36e9

(4620)

on July 20, 2011
at 11:09 PM

I asked him for a source for his statement in the comments. We shall see if he delivers.

9d43f6873107e17ca4d1a5055aa7a2ad

on July 20, 2011
at 08:26 PM

is today "invasion of the people who think paleo was low-carb" day?

9d43f6873107e17ca4d1a5055aa7a2ad

on July 20, 2011
at 08:18 PM

huh wavehunter, that creates a type of starch called resistant starch ,which is supposed to be harder to digest...

36b7a2776d028dc8d5743e2e56ece34d

(812)

on July 20, 2011
at 07:39 PM

@Melissa- have you tried double baking a potato?(baking than letting it cool off then heating it up again, or you could just eat it slightly warm without heating it up again). I couldn't eat many potatoes but when I let them cool down they get more gelatinous like rice and have a better texture. Fat/spices also coat the outside of the potato granules instead of mixing in so overall it tastes a lot better.

76f3ead3aa977d876bcf3331d35a36e9

(4620)

on July 20, 2011
at 07:36 PM

Uh oh. Looks like I've been atomic bombing my health by eating fat/starch for majority of my meals in the last year. I actually feel incredibly satiated with the fat/starch combo, and have no desire to overeat. This may be a stupid question, but what's a jo-jo?

Af1d286f0fd5c3949f59b4edf4d892f5

(18452)

on July 20, 2011
at 07:30 PM

i think there are many other foods that i would call the atomic bomb of health before branding Fat/Starch combo with that label.

76f3ead3aa977d876bcf3331d35a36e9

(4620)

on July 20, 2011
at 07:07 PM

Verrry interesting. Actually, the more I think about it, the more I think this "fat coats starch" idea of Don's sounds like some sort of fat fear-mongering. I'd really like to see the evidence for it, and may call him out about it in the comments. I'm with you both on the rice thing. Perhaps it has to do with the fact that white rice is almost pure starch, whereas tubers and plantains have some indigestible carbs (raffinose, etc.)

50637dfd7dc7a7e811d82283f4f5fd10

(5838)

on July 20, 2011
at 07:02 PM

Intersting. I've recently added basmati rice to my daily menu, and I handle it a lot better than I thought I would have. Now that I think of it, potato seems to make me more gassy than the rice.

9d43f6873107e17ca4d1a5055aa7a2ad

on July 20, 2011
at 06:50 PM

I'm not sure to be honest. Can't find any papers on this effect. For me it has to do with the type of starch. I can eat buckets of rice in coconut milk without ever having a problem. But can only tolerate some many plantains and potatoes a day. I think it's a one potato max for me a day and it has nothing to do with whether I eat it with fat or not.

50637dfd7dc7a7e811d82283f4f5fd10

(5838)

on July 20, 2011
at 06:22 PM

Melissa, have you had success with balancing the fat:starch? By success, I mean a sweet spot for that ratio?

76f3ead3aa977d876bcf3331d35a36e9

(4620)

on July 20, 2011
at 06:08 PM

Never said it was a bad thing. Mostly just curious as to where Don is getting this info from and potential consequences for people suffering from indigestion and combining fat/starch (if this theory is true). And yeah, I have more gas on a low-fat diet too.

9d43f6873107e17ca4d1a5055aa7a2ad

on July 20, 2011
at 06:03 PM

why is this a bad thing? Your gut flora need to eat too so they can make SCFA. The secret is to balance the fat:starch so you have some going to the colon, but not too much (that can lead to gas/overgrowth). I'd like to see more evidence though that fat impairs starch digestion. My own experience is that I have more issues with gas on a lower-fat diet.

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3 Answers

3
531db50c958cf4d5605ee0c5ae8a57be

on July 20, 2011
at 08:57 PM

Sounds like Don's making stuff up again...

76f3ead3aa977d876bcf3331d35a36e9

(4620)

on July 20, 2011
at 11:09 PM

I asked him for a source for his statement in the comments. We shall see if he delivers.

531db50c958cf4d5605ee0c5ae8a57be

(8878)

on July 21, 2011
at 04:18 PM

Good luck with that!

1
6120c989fd5b69f42a0834b69b87955b

(24553)

on July 20, 2011
at 08:01 PM

This might explain what I've been calling the "croissant paradox". I normally don't do well with bread both for gluten and glycemic reasons, but when I eat a croissant (has to be from a good French bakery) my energy seems pretty stable and I don't notice the normal gluten side effects that one wouldn't want to discuss in polite company. I've been picturing the butter creating a protective bubble around each little speck of flour to guide it safely through my small intestine. I'm probably wrong about the mechanism, but that's the best I've come up with so far.

E48833ca4e98b24f35191a02e84cc262

on July 21, 2011
at 02:08 AM

Croissants...damn, hide the nutella quick....

-2
Medium avatar

(10611)

on July 20, 2011
at 07:25 PM

Fat/starch is the atomic bomb for health. Fat is the big calorie fellow traveler that moves 100 calories of potato to 500 calories of jo-jos. AND makes the potato infinitely more easy to overeat.

So nothing good comes from this combination. Blending fat with starch drives down glycemic index - through the effect of mixing in the 0 GI fat - but it doesn't change the energetic effect. Not a good digestive lever IMHO.

531db50c958cf4d5605ee0c5ae8a57be

(8878)

on July 21, 2011
at 04:20 PM

Don't know what "jo-jos" are but my guess is you'll find few people on this site that eat donuts on a regular basis...

Medium avatar

(10611)

on July 21, 2011
at 10:00 PM

I realize people here are not affected by the radioactivity of the fat/carb complex. But it's a prime cause of obesity in the world at large. I'm talking Snickers, pizza and donuts as regular diet; not an occasional croissant made with Kerrygold. But whether the fat is lard, trans or PUFA, I don't see any synergistic good combination. And a Jo-Jo is a wedge cut potato deep fat fried in mystery oil, covered with orange salty powder and served in a tray with ranch dressing. Overeating them made me obese.

76f3ead3aa977d876bcf3331d35a36e9

(4620)

on July 20, 2011
at 07:36 PM

Uh oh. Looks like I've been atomic bombing my health by eating fat/starch for majority of my meals in the last year. I actually feel incredibly satiated with the fat/starch combo, and have no desire to overeat. This may be a stupid question, but what's a jo-jo?

Af1d286f0fd5c3949f59b4edf4d892f5

(18452)

on July 20, 2011
at 07:30 PM

i think there are many other foods that i would call the atomic bomb of health before branding Fat/Starch combo with that label.

Medium avatar

(10611)

on July 21, 2011
at 01:57 AM

Well downvote me all you like but stay away from the jo-jos and donuts on the next trip to the jiffy mart. Trans fat anyone?

9d43f6873107e17ca4d1a5055aa7a2ad

on July 20, 2011
at 08:26 PM

is today "invasion of the people who think paleo was low-carb" day?

Medium avatar

(2417)

on December 12, 2012
at 08:57 AM

Why the down votes? He's 100 percent correct. Guess its a case of shoot the messenger when the message is something that conflicts with what folks desire. Fat plus starch at the same meal is the EASIEST way to get fat yourself, hands down, for myriad reasons.

Medium avatar

(10611)

on December 13, 2012
at 01:29 PM

I used to have 5 downvotes on this. Attitudes have changed here. The fat/starch combo encompasses almost every processed and comfort food. People are touchy about the fat part, but the fat is high calorie PUFA's. And now one of the biggest providers - Hostess - is gone. A good thing.

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