Thread by @angryhacademic

for those who missed my @aberdeen_ucu talk today on #sugar, #breakfast, #health & #appetite, a wee thread on the fascinating properties of sugar...
full talk (poor sound qual) can be found here:

1/21

#sugar is demonised in the media, literally described as "evil". myths include: its addictive, causes cravings, makes you hungry, makes you overeat, makes you gain weight.

current #publichealth guidelines target reducing sugar
2/21

#breakfast is touted the "most important" meal of the day. what does "important" mean?

breakfast is the highest #sugar meal of the day so a good meal to target to reduce total sugar.

breakfast = complex to define, but broadly breaks the overnight fast (break-fast) 3/21

your body has circadian rhythms, most obvious = sleep/wake cycle. cells/organs also have circadian rhythms. related to sugar, (biological) morning ingestion of sugar gives a quicker and lower #bloodsugar response, and a quicker #insulin response pnas.org/content/112/17… 4/21

this means #sugar is being cleared from the blood quicker, i.e. insulin is more efficient at getting glucose out of circulation and into cells. this is good.

so if we are going to eat sugar, probably eating it in the morning is least detrimental to #health 5/21

sweet taste receptors may also have a circadian (diurnal) rhythm = taste sweetness more intensely in the morning vs evening. so any #health or #appetite effects (good or bad) of sweet taste might be amplified in the morning

pubmed.ncbi.nlm.nih.gov/18633111/ 5/21

when you taste sweetness, you get a cephalic phase #insulin response; basal insulin can double (for ~10 min), helping to mitigate post-ingestive high #bloodsugar

pubmed.ncbi.nlm.nih.gov/6364839/

early insulin responses = healthier blood sugar regulation

pubmed.ncbi.nlm.nih.gov/11063282/ 6/21

contrary to media rhetoric, #insulin is a satiety hormone

ncbi.nlm.nih.gov/pmc/articles/P…

stronger glucose/insulin responses = greater (acute) satiety
pubmed.ncbi.nlm.nih.gov/11477506/
pubmed.ncbi.nlm.nih.gov/12399274/

so maybe: morning = ↑ sweet taste = ↑ insulin = ↑ satiety? 7/21

sweet taste receptors are found in many cells across the body.

in the brain, they help regulate appetite, and this gets disrupted with #obesity
pubmed.ncbi.nlm.nih.gov/27388805/ 8/21

in the gut, sweet taste receptors are found on L cells which secrete GLP-1 when stimulated

ncbi.nlm.nih.gov/pmc/articles/P…

GLP-1 is a satiety hormone (makes you feel full), an incretin hormone (stimulates insulin), and reduces food reward (so you don't *want* to eat more) 9/21

in the pancreas, sweet taste receptors aid in #insulin secretion

pubmed.ncbi.nlm.nih.gov/19352508/

and stimulation of these receptors may help prevent pancreatic beta cell (the cells that produce insulin) death

ncbi.nlm.nih.gov/pmc/articles/P… 10/21

therefore, having some sugar likely helps overall in pancreatic health, appropriate #insulin secretion, and feeling full. these effects *might* be even stronger in the morning but that's quite an inference at this stage. 11/21

the idea that #sugar makes your #bloodsugar spike and crash is also worth debunking. figure 2 (in link) shows what happens when we feed 75 g of pure liquid glucose within 5 minutes to participants after an overnight fast (i.e. empty stomach):
journals.physiology.org/doi/full/10.11… 12/21

this is over a 2 h time period - no rapid spike, no crash. insulin & glucose show a well controlled homeostatic response

to put this in context: 2 cans of coke = ~75 g sugar. ~50 % of this sugar is #fructose (doesnt effect #bloodsugar). 13/21

so to get ~75 g GLUCOSE = ~4 cans of coke

in a breakfast context - of 101 UK breakfast cereals i looked at, @KelloggCompany Frosties had the highest #sugar (37 % by weight). if you had a large portion (50 g) + 250 mL semi skimmed milk = ~30 g sugar 14/21

(total carbohydrates = ~56 g). still nowhere near the 75 g glucose.

also consider:
1. ~half the sugar will be fructose = doesn't affect your #bloodsugar
2. the sugars are in a food matrix = slower digestion, some won't get absorbed, etc 15/21

so it would be surprising if your large sugary cereal gave you a rapid spike and crash when we can't even achieve that with 75 g pure liquid glucose

(in healthy adults) 16/21

considering this, it's unsurprising that:
1. #carbohydrate and #sugar are inversely associated with #obesity
onlinelibrary.wiley.com/doi/epdf/10.11…
2. when people cut out sugar and lose #weight, they have just cut total calories (ie. nothing magic about sugar)
bmj.com/content/346/bm… 17/21

3. there's no associated between #carbs, #sugar, #insulin resistance, and #diabetes
pubmed.ncbi.nlm.nih.gov/19207533/

to top it off, my research showed 3 wk plain vs sweet (same calorie, 30 % by weight sugar) #breakfast had NO DIFFERENCE in:

onlinelibrary.wiley.com/doi/full/10.10…
18/21

❌body mass
❌energy intake
❌physical activity
❌fasted biomarkers of health (glucose, TAG etc)
❌fasted appetite hormones (GLP-1, FGF21)
❌psychological approach to food
❌cravings
❌liking of plain or sweet porridge
❌*post-breakfast sugar intake*
19/21

we did find:
✅after sweet breakfast a REDUCTION for sweet desire (back to baseline levels by lunch (as predicted by sensory specific satiety)

20/21

overall, my take on all this is that if you enjoy #sugar then moderate consumption is ay okay in healthy adults.

if you need to lose weight, targeting any nutrient or meal can do the trick; for some this might be cutting #breakfast or #sugar 21/21

PS. thanks to everyone who attended today, hope you found it interesting. next talk is in 2 week on #hydration and i shall debut the new theory i've been working on!

tweets 17 and 18 have relevant links @mrc314 @AmandaZZ100

preempting based on experience - before critiquing, please consider if this evidence showed eg low carb was ok, would you accept it as good enough evidence?