From Blood Sugar is Stable:-
In a healthy person, BG (blood glucose) is held at a fairly constant value with slowly-varying glucose inputs (except after high-GL meals, which produce rapidly-varying glucose inputs) by a NFB (negative feed-back) loop. See Blood Glucose, Insulin & Diabetes.
When protein is eaten, this produces a glucagon response from pancreatic alpha cells, which tries to raise blood glucose level by stimulating the liver to convert liver glycogen plus water to glucose. Protein also produces an insulin response from pancreatic beta cells, which tries to lower blood glucose level by a) increasing glucose uptake from the blood and b) inhibiting HPG (hepatic glucose production). The net result is no change in BG level.
In extended fasting or on VLC (very low carbohydrate)/ketogenic diets, there's no liver glycogen left after ~1 day.
∴ The glucagon response has no effect on HGP.
The insulin response still has an effect, until physiological IR* develops.
∴ Blood glucose tries to decrease, but the HPAA keeps it steady by raising cortisol level.
RE How eating sugar & starch can lower your insulin needs: Blood glucose level on a VLC/ketogenic diet can be RAISED, due to the BG NFB HPAA (hypothalamic pituitary adrenal axis) loop not having a precise set point with the cortisol/adrenaline response (hyperglycaemia is not fatal, whereas hypoglycaemia can be fatal, as the brain always needs some glucose to function (~50%E from glucose)).
So, how come people on LCHF (low carbohydrate, high fat) diets can have normal or slightly low BG levels?
1. Luck. The BG NFB HPAA loop isn't very precise.
2. Excessive intake of Booze. Ethanol inhibits HGP (dunno about RGP (renal glucose production)).
3. Insufficient intake of Protein. This deprives the liver & kidneys of glucogenic amino acids (Alanine & Glutamine are the 2 main ones), forcing BG down and making the HPAA run open-loop and raise cortisol level. There's another source of Alanine & Glutamine available - Lean Body Mass. Uh-oh!
Consuming more protein on extended fasting or a VLC/ketogenic diet can result in higher BG level for three reasons.
1. It allows the HPAA to run closed-loop, as it's supposed to.
2. The lack of a 1st phase insulin response in people with IR/IGT/Met Syn/T2DM* results in a temporary BG level spike with the intake of rapidly-absorbed proteins e.g. whey. There's an unopposed glucagon response, until the 2nd phase insulin response begins.
See http://care.diabetesjournals.org/content/early/2015/11/29/dc15-0750.abstract
*Long-term drastic carbohydrate restriction kills the 1st phase insulin response! See http://carbsanity.blogspot.co.uk/2013/10/insulin-secretion-in-progression-of.html
P.S. This only applies to people who have sufficient liver glycogen, due to them eating some (50 to 100g/day, say) carbohydrate.
3. Hepatic Insulin Resistance results in the insulin response inadequately suppressing Hepatic Glucose Production. As 50g of protein (an 8oz steak, say) yields ~25g of glucose from glucogenic amino acids, there's an increase in the amount of glucose entering circulation, which raises BG level.
See http://bja.oxfordjournals.org/content/85/1/69.long
Nutritional Ketosis etiketine sahip kayıtlar gösteriliyor. Tüm kayıtları göster
Nutritional Ketosis etiketine sahip kayıtlar gösteriliyor. Tüm kayıtları göster
11 Aralık 2015 Cuma
In starvation or ketosis, protein should have NO EFFECT on blood glucose level, not RAISE it.
Etiketler:
Benign Dietary Ketosis,
Blood glucose,
Glucagon,
Hepatic glucogenesis,
Insulin,
Insulin Resistance,
Ketogenic diet,
Nutritional Ketosis,
Protein,
Renal glucogenesis,
Starvation
11 Temmuz 2014 Cuma
15 Haziran 2014 Pazar
I'm NOT a lipophobe, I'm a very naughty boy!
First, postprandial triglycerides again. From Fasting Compared With Nonfasting Triglycerides and Risk of Cardiovascular Events in Women, here's a plot of HR for future CHD vs TG's at various times after eating.
Notice how the HR falls with increasing time from last meal. As TG's ≥12 hours after eating are a surrogate for Insulin Resistance (IR) and the HR is only 1.04 (95% CI 0.79 - 1.38), this strongly suggests that IR is not a significant factor.
It's been suggested that IR might increase PP TG's in the 2 - 4 hour period due to impaired clearance. According to Fig. 3B in Extended effects of evening meal carbohydrate-to-fat ratio on fasting and postprandial substrate metabolism, TG clearance in healthy men doesn't significantly start until after 4 hours has elapsed. Therefore, an impairment in TG clearance isn't going to make a significant difference to TG level in the 2 - 4 hour period.
Second, the reason why I'm having to repeat myself is due to Cholesterol: Do chylomicrons clog your arteries? (2), where I've been called "my resident lipophobe". As I drink Gold Top milk (5.2g of fat/100mL) and eat pork including belly slices (you know, those strips of pork with a lot of fat on them), I'm being attacked for something that I'm not.
What I'm criticising is dietary extremism. Eating fats in foods is fine by me, but eating sticks of Kerrygold butter and/or dumping loads of butter and/or MCT oil into coffee to achieve "Nutritional Ketosis" is not a good idea. Anyway, here's an amusing spoof on Bulletproof coffee.
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Hazard ratio (HR) and 95% confidence interval (CI) for highest vs lowest tertiles of triglyceride level (see Table 3 for values), adjusted for age, blood pressure, smoking, hormone use, levels of total and high-density lipoprotein cholesterol, diabetes mellitus, body mass index, and high-sensitivity C-reactive protein level. |
Notice how the HR falls with increasing time from last meal. As TG's ≥12 hours after eating are a surrogate for Insulin Resistance (IR) and the HR is only 1.04 (95% CI 0.79 - 1.38), this strongly suggests that IR is not a significant factor.
It's been suggested that IR might increase PP TG's in the 2 - 4 hour period due to impaired clearance. According to Fig. 3B in Extended effects of evening meal carbohydrate-to-fat ratio on fasting and postprandial substrate metabolism, TG clearance in healthy men doesn't significantly start until after 4 hours has elapsed. Therefore, an impairment in TG clearance isn't going to make a significant difference to TG level in the 2 - 4 hour period.
Second, the reason why I'm having to repeat myself is due to Cholesterol: Do chylomicrons clog your arteries? (2), where I've been called "my resident lipophobe". As I drink Gold Top milk (5.2g of fat/100mL) and eat pork including belly slices (you know, those strips of pork with a lot of fat on them), I'm being attacked for something that I'm not.
What I'm criticising is dietary extremism. Eating fats in foods is fine by me, but eating sticks of Kerrygold butter and/or dumping loads of butter and/or MCT oil into coffee to achieve "Nutritional Ketosis" is not a good idea. Anyway, here's an amusing spoof on Bulletproof coffee.
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