Javier Gonzalez Profile picture
Physiologist interested in human fuel use Views my own (obv) #nutrition | #exercise | #carbohydrate | #metabolism | #cycling | #science
Seanmo413 Profile picture 1 subscribed
Mar 31, 2023 10 tweets 4 min read
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
Feb 23, 2023 14 tweets 6 min read
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
Dec 8, 2022 8 tweets 4 min read
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
Nov 30, 2022 12 tweets 7 min read
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
Nov 3, 2022 11 tweets 6 min read
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
Oct 22, 2022 12 tweets 7 min read
Why do some people "backload" carbs?

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

A 🧵 1/12

#exercise #carbs #lowcarb #lchf Image "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 Image
Oct 16, 2022 10 tweets 4 min read
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…
Oct 11, 2022 8 tweets 4 min read
Do doses of fat respond the same way as glucose?

A 🧵 1/8

#metabolism #fat #nutrition #diet 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
Oct 7, 2022 5 tweets 2 min read
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
Oct 3, 2022 8 tweets 4 min read
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/
Oct 2, 2022 8 tweets 3 min read
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)
Sep 28, 2022 7 tweets 2 min read
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
Sep 5, 2022 9 tweets 4 min read
Thanks for the guesses.

A: Exercise!

Group 1: Trained
Group 2: Untrained

Thread 🧵 1/9

#exercise #glucose #metabolism 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
Aug 31, 2022 13 tweets 6 min read
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
Aug 19, 2022 9 tweets 4 min read
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