In starvation or ketosis, protein should have NO EFFECT on blood glucose level, not RAISE it.

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

Another penny drops: Why severe hyperinsulinamia can occur with a small increase in exogenous carbohydrate intake.

This blog post is a result of Vim's comments in the previous blog post. A penny suddenly dropped!

From http://bja.oxfordjournals.org/content/85/1/69.full

Insulin has a Chalonic (inhibitory) action on blood glucose level (via the liver, muscle mass & fat mass), blood FFA level (via fat mass) and blood ketone body level (via the liver).

As mentioned in the comments, GHB has a stimulant effect - up to a certain level of blood GHB. Beyond that level, there's a powerful sedative effect. This is because at low levels of exogenous ketone body input, insulin secretion increases slightly to reduce hepatic ketogenesis.

At a certain level of exogenous ketone body input, hepatic ketogenesis falls to zero and cannot be reduced any further. Any slight increase beyond this point in exogenous ketone body input, results in a large increase in insulin secretion, as the pancreas increases Ketone body-Stimulated Insulin Secretion to maximum in a (failed) attempt to reduce blood ketone body level.

Exactly the same thing happens with exogenous carbohydrate or BHB input.

At a certain level of exogenous carbohydrate input, hepatic glucogenesis falls to zero and cannot be reduced any further. Any slight increase beyond this point in exogenous carbohydrate input, results in a large increase in insulin secretion, as the pancreas increases Glucose-Stimulated Insulin Secretion to maximum in a (failed) attempt to reduce blood glucose level.