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Study investigates how dietary fat can affect insulin dosing in type 1 diabetes

DCUK NewsBot

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In both the USA and UK, people with type 1 diabetes are recommended to adjust insulin for dietary fat. It is known that combining fat with carbohydrate at meals can slow how quickly food is absorbed and this can affect the required timing and dose of insulin. To date, the optimal way of adjusting doses in response to differing levels of fat in a meal has not been known. However, a new study, by researchers from Australia and the USA, has investigated the dose adjustments needed for handling differing levels of fat for people with type 1 diabetes using insulin pumps. The research involved participants having meals with 45g of carbohydrate and with 0g, 20g, 40g or 60g of fat. The participants attended the research clinic on nine to 12 occasions. To control blood glucose levels, participants used their own insulin to carbohydrate ratios and took a dual-wave bolus dose on their pumps, with the amount of insulin split 50/50 between the two waves over hours. A dual wave bolus involved an immediate initial bolus of insulin followed by a second bolus delivered gradually over a set period of time. The researchers found that the more fat the meals contained, the lower blood glucose levels were in the first two hours of eating the meal and the higher blood glucose levels were in two to five hours after eating. In subsequent visits, participants repeated the meals, but a model was used to predict the insulin dosing. The experiments to get the right doses were done until good blood glucose control was achieved. The findings of these further experiments allowed the researchers to see what split of insulin dosing was needed to achieve good control. The results showed that, for the 20g of fat meal, a dual-wave bolus was delivered over 73 minutes. This meal required 6% more insulin than the meal without fat and the split of insulin across the two waves of the dual-wave bolus was 74% of the dose for the first wave and 26% of the dose for the second wave. For the 40g of fat meal, a dual-wave bolus was delivered over 75 minutes. This meal also required 6% more insulin than the meal without fat and the split of insulin across the dual-wave bolus was 63% of the dose on the first wave and 37% for the second wave. Finally, the 60g of fat meal required the dual-wave bolus to be delivered over 105 minutes. The meal required 21% more insulin than the meal without fat. The split of insulin across the two waves of bolus were 49% of the dose for the first wave and 51% for the second wave. The results are fascinating to see and may help to inform future recommendations of insulin dose adjustment for meals involving dietary fat. As insulin dosing can vary significantly from one individual to another, it is best to discuss insulin doses with your diabetes health team if you feel you may benefit from a significant dose adjustment. Your diabetes health team can help you to make dosing adjustments with the right precautions for safety. The study is published online, ahead of print, by the Diabetes Care journal.

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When protein started increasing my bgs in carb absence I used fatty protein to beat liver dumping to great success. Fat in any diet slows the digestion, for me (I'm on insulin).
 
ickihun said:
When protein started increasing my bgs in carb absence I used fatty protein to beat liver dumping to great success. Fat in any diet slows the digestion, for me (I'm on insulin).
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sorry what do you mean by burnout?
 
Whenprotein started increasing my bgs in carb absence I used fatty protein to beat liver dumping to great success. Fat in any diet slows the digestion, for me (I'm on insulin).

tina t said:
sorry what do you mean by burnout?
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I didn't mention burnout, sorry.
 
If I'm reading it correctly, it's saying that for a set amount of carbs, as the proportion of fat rises, overall insulin increases and the split gets increasingly weighted towards the second dose.

I reckon this would broadly apply to MDI too.

And for recently dx'd T1s who are not yet familiar with the idea of splitting, practice on generally fat free-ish dishes to get some general ground rules in place before moving on to understand the absorption issues which increasing fat ratios introduce.
 

I'm on MDI and I sometimes split my dose.
 
Robinredbreast said:
I'm on MDI and I sometimes split my dose.
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Yeah, me too.

It's something I don't really remember being taught about when I was first dx'd, mind you, I think I was on mix for a while to start with, so not really possible with that.

Wasn't really till about 3yrs ago after I went on DAFNE, got libre and read Sugar Surfing that I realised, jeesh, no-one told me about all these fancy, modern techniques!
 
So, the researchers have just rediscovered the 'pizza effect'?
 
This implies that a larger amount of insulin is needed if you eat more fat and not just that you need to split dose either via 2 jabs or 2 waves, and increase the dose in the second jab. However the amounts don't seem too massive (you would definitely need to be on a pump to adjust your bolus by 6%!).
If no carbs are eaten, I find that fat only has little impact on my blood sugar but that I do need to dose for protein (gluconeogenesis is much less efficient at raising blood glucose so it ends up being a minimal dose).
I'd rather not eat fat and carbs because a) they are hard to dose for b) they make ti very easy to store the fat as fat whilst your body fuels itself from the glucose and can easily park the rest around your stomach or bottom with all that insulin that's needed to cover the glucose.
 
Shiba Park said:
So, the researchers have just rediscovered the 'pizza effect'?
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To be fair, they're not saying they've discovered it - the linked report says that ADA already advises to adjust for fat, and the linked report seems to be an attempt to quantify by how much as a rough benchmark instead of the "winging it" which we can sometimes be prone to do.

Maybe input like this will find its way into predictive simulators like in xDrip+ in the fullness of time, who knows.
 

When I did my carb counting course, about 8 to 10 years ago ( this was the first time I was introduced to pens) at my hospital, it was only the carbs that we had to bolus for, but times have changed.
Fat does affect our BG.
 
Robinredbreast said:
When I did my carb counting course, about 8 to 10 years ago ( this was the first time I was introduced to pens) at my hospital, it was only the carbs that we had to bolus for, but times have changed.
Fat does affect our BG.
Click to expand...

We need to be a scientist and a mathematician, plus, have a whole lot of patience too
 
Robinredbreast said:
We need to be a scientist and a mathematician, plus, have a whole lot of patience too
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Native T1 instinct and intuition, Robin, we're all geniuses!

One of the interesting things I'm finding with using libre/MM/xDrip+ as a cgm is that if I do a reasonable carb count, and then take a general view on how fatty or non-fatty the meal is, I can say, ok, x units for that just now, maybe some later, then keep an eye on how the cgm trace is panning out, and do the second part of the split when I see what looks like might become a pronounced rise a few hrs later if I don't pin it.

I like my tech, but have never been one for writing things down in notebooks or overthinking them too much - heck, who wants to fat count as well as carb count, flippin meal will have gone cold by the time I do that - so, my current approach is, "cgm-assisted winging it."
 
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