HOW ACCURATE IS YOUR GLUCOSE MONITOR?

Our latest paper shows that a continuous glucose monitor (CGM) can overestimate blood glucose, and the size of this bias varies by person and the meal/beverage ingested… see below for more



@AJCNutrition ajcn.nutrition.org/article/S0002-… CGMs measure glucose in interstitial fluid, then use algorithms to estimate what the blood glucose concentration is

Many factors could affect the ability for a CGM to accurately estimate blood glucose, and these could vary between people and when glucose fluxes are changing

INDUSTRY BIAS IN NUTRITION RESEARCH?

One type of bias is publication bias (aka desk draw bias)

Not publishing some studies due to the direction or strength of their findings

eg. if findings do not conform to a hypothesis

Is there evidence of this bias in nutrition research? Funnel plots are an objective way to assess for evidence of publication bias

Asymmetry of association strength/effect size versus precision of estimate = evidence of publication bias

What happens if people restrict either dietary #sugar or all carbohydrates (#ketogenic diet)?

🍝vs🍬vs🥓

Our latest 📝 assessed energy expenditure 🏃‍♀️, energy intake 🍽️ metabolism 🩸💪🏻 and other outcomes

A 🧵

🔗

#lowcarb #keto #diet #food doi.org/10.1016/j.xcrm…


What did we ask people to do and did they do it?

People were asked to stick to these 3 diets

They could eat as much/as little as they liked as long as they stuck to these ratios

Urinary ketones confirmed people were in ketosis on the low carb (LOWCHO) diet

Are women more or less variable than men when it comes to metabolism?

Are there implications for excluding men/women from specific studies?

Check out our latest paper led by @lfbradshaw @JariyaBuniam exploring this

🔗
#sex #gender #female #women
🧵 👇 doi.org/10.1152/japplp… The idea that males display more between-individual variance than females has been considered for >150 years

In humans, this might be (partly) due to averaging of two parental copies in the homogametic sex but not in the heterogametic sex.

Should people be concerned with blood glucose concentrations if they don’t have prediabetes or diabetes?
1/10

#glucose #health #biohack #science #metabolism #cgms #hba1c #sugarspikes For context, the relationship between LDL-cholesterol concentration and coronary heart disease risk appears linear across the entire physiological range

What about glucose?
2/10

If you start running daily and burn 500 kcals on the🏃‍♀️will this increase total daily calorie burn by 500 kcals or not?

Yes = ADDITIVE (Panel A)
No = CONSTRAINED (Panel B)

Take the poll👇 & read the 🧵to find out more
1/14
#metabolism #energy Does increasing physical activity directly add to total energy expenditure (ADDITIVE)

or

is total energy expenditure constrained by compensatory reductions in other components (CONSTRAINED)?
2/14

De Novo Lipogenesis (DNL) is the production of fat (lipids) from other sources

E.g., conversion of sugars to fats

So what happens to DNL if calorie intake is restricted?

A 🧵that might surprise you...
1/8

doi.org/10.1113/JP2777…
#fasting #science #nutrition #metabolism First, a quick poll before reading on

If mice 🐁 are calorie restricted 🍽️ for a prolonged period of time (provided 30% fewer calories than they would choose to eat normally at baseline), what will happen to DNL?
2/8

How can carbohydrate metabolism be measured during exercise?

🍏🍌🍞🍝🍚🚴‍♀️🚴‍♂️⛹️⛹️‍♂️

New #openaccess review by @AndyJKing & I in @IJSNEMJournal

Hopefully a useful resource for people researching & reading about exercise metabolism 👩‍🔬📖

A summary🧵1/12

doi.org/10.1123/ijsnem… What are isotope tracers?

Molecules where certain elements (e.g. Carbon) differ in some ways (mass) but less so in others (function)

This means we can distinguish between "label" and naturally occurring molecules, whilst the label behaves similarly to the natural molecule
2/12

Restricting total carbs has a much bigger effect than just restricting sugars in the first 24 hours

Check out our latest study (led by @AaronHengist) on carb and sugar restriction 🧵 (1/11)

doi.org/10.1007/s00394…

#lchf #lowcarb #carbs #highfat #keto #ketogenic #diet #health The main aim was to see if restricting sugars or total carbs alters physical activity levels

This is because previous studies suggested fasting can lower physical activity & this can happen quickly

We wanted to know if this was due to carbs or energy

What did we find?
2/11

Why do some people "backload" carbs?

What does this mean and what is the science behind it?

A 🧵 1/12

#exercise #carbs #lowcarb #lchf "Carb backloading" is the practice of avoiding carbs early in the day and eating them later in the day, usually after some exercise.

Why would this make sense to do?
2/12

There is no evidence that sugar directly causes any negative health effects.

Is this true?

A 🧵
#sugar #health #metabolism
1/10 Latest UK guidelines suggest there is only sufficient evidence that diets high in sugars:

1) cause increased calorie intake
2) are associated with tooth decay

So if calorie intake is not maintained, there are no harmful effects of sugars?

2/10

assets.publishing.service.gov.uk/government/upl…

Do doses of fat respond the same way as glucose?

A 🧵 1/8

#metabolism #fat #nutrition #diet

https://twitter.com/Gonzalez_JT/status/1576495111139053569

This time, the measure of interest is the level of fat in the blood (triacylglycerol; aka TAG)

When fasted, levels of TAG are low (left)

High levels of TAG make the plasma part of blood look cloudy/turgid (right)

2/8

Which fuels do human foetuses use?

This may surprise you... (1/5)🧵 First, how do we even know what the human foetus uses as a fuel?

The amount of carbon dioxide released relative to the amount of oxygen used (aka RER or RQ) is a good marker of fuel use.

But how can this be measured in a human foetus?
2/5

Which of these will produce the biggest blood sugar response?

75 g glucose alone

75 g glucose + 7.5 g fructose?

🧵 1/8 Adding 7.5 g fructose to 75 g glucose reduces the blood glucose response.

Since this is more total carbohydrate ingested with 75 g glucose + 7.5 fructose why is the blood glucose response lower? 2/8

pubmed.ncbi.nlm.nih.gov/11134101/

Q: Which of these would produce biggest the blood sugar response?
(i.e., biggest change in glucose concentration)

Answers below (1/8) 🧵 #glucose #health #metabolism Have a guess here before reading on to find out if you are right... (2/8)

Have a guess what these people did at timepoint 0-300 mins in this study.

The read the 🧵 to find out if you are right... (1/7) A reasonable guess would be that they ate some carbs at 0 min and then stopped eating because glucose dropped to fasting levels by hour 3.

That isn't what they did here...(2/7)

Study 🔗: journals.physiology.org/doi/full/10.11…
Led by @27CJ

Thanks for the guesses.

A: Exercise!

Group 1: Trained
Group 2: Untrained

Thread 🧵 1/9

#exercise #glucose #metabolism

https://twitter.com/gonzalez_jt/status/1566518864132857857

Here is the original figure

Note the remarkable increase in glucose immediately after intense exercise (110% VO2 max)

So whats going on here?
2/9

Great to see this new research out in @IJSNEMJournal led by @timpodlogar

A 🧵 to give a bit more background...

#cycling #LaVuelta22 🍚🍌🚵
1/13 Athletes commonly train almost everyday (and sometimes multiple times a day), so carbohydrate stores are often being depleted and need replenishing.

A goal of a pre-competition breakfast is to keep carbohydrate stores (glycogen) topped up
2/13

I often hear people say venous blood samples are preferable to capillary (fingertip/earlobe) samples.

Why then, do the glycaemic index guidelines make the following recommendation?

pubmed.ncbi.nlm.nih.gov/19079901/

Let’s look a little deeper into this… 🧵 1/9 #glucose #metabolism We will focus here on glucose concentrations.

With glucose tolerance tests or other postprandial tests, a common aim is to understand the ability of the person to maintain relatively stable glucose concentrations.

I.e. the outcome of the integrated response from all organs
2/9