Gluconeogenesis from Reader
Fat burning hormones only work when insulin is at normal levels.
It seems to me taking honey/fructose just before bed will raise insulin and delay the release of these fat burning hormones until things are back to normal.
This I would have thought would be particularly true for someone who already has their blood sugar under control through low carbing.
You may well be talking about people who are on a normal high carb diet whose blood sugars are unstable by the time they go to bed. But during the night when more blood sugar is needed it is the job of the liver to make some more. It does this by a process called gluconeogenesis when most of the fat burning will take place. But this process only kicks off when the body needs to make more blood sugar and there are no carbs or stored glycogen to burn. So feeding a high sugar snack to a body which already has stable blood sugar will only delay this process.
With high carb dieters it may well help but I suspect not with low carbers.
This is one take on recovery biology I would like to see how you would react to this in favour of the hibernation diet?
RegardsOliver
posted by Hibernation Diet Blogger @ 11:40 AM
1 Comments:
Oliver,
Thank you for raising these important questions. I have highlighted my replies.
"Fat burning hormones only work when insulin is at normal levels."
Insulin is suppressed during exercise and yet we do burn fat during exercise, although it is only a small portion of total metabolism.
Therefore it is incorrect to state that insulin must be at normal level to allow fat burning to take place.
Insulin is a fat storage hormone and also promotes fat synthesis, hence syndrome X, which is caused by hyperinsulinism, and results in insulin resistance, obesity and heart disease.
"It seems to me taking honey/fructose just before bed will raise insulin and delay the
release of these fat burning hormones until things are back to normal."
Fructose is taken up by the liver and fructose will allow glucose uptake also, via translocation of the glucose enzyme (glucokinase).
Both will be converted to glucose and glycogen, thus providing good liver glycogen plenitude or the 8 hours of the night fast.
Therefore little of the fructose/glucose from honey will escape the portal circulation.
The small amount of glucose that does appear in the general circulation will cause a small insulin spike, entirely beneficial, insulin promotes sleep via tryptophan, serotonin and melaonin.
The melatonin then inhibits insulin, preventing a fall in blood glucose.
This gorgeous cycle (honey, insulin, melatonin cycle) is exactly what is required to promote recovery (fat burning ) biology.
Melatonin acts to stabilise blood glucose during the night fast by restraining insulin.
Melatonin also promotes release of growth hormone, a key recovery and fat burning hormone.
"I would have thought would be particularly true for someone who already has their blood sugar under control through low carbing."
Low carbing, is a vague term and if it ignores the liver glycogen store will result in chronic overproduction of the adrenals causing a variety of adrenal driven conditions, osteoporosis, diabetes 2, infertility, memory loss, depression, heart disease - all cortisol and adrenaline driven.
"You may well be talking
about people who are on a normal high carb diet whose blood sugars are unstable by the time they go to bed."
A normal high carb diet is also too vague a term.
Often a high carb diet high in refined sugars will activate fat synthesis via hyperinsulinism.
This results in the sugars being converted to fats, leading to poor formation of liver glycogen and also, as in low carb diets, resulting in chronic activation of the adrenals.
"But during the night when more blood sugar is needed it is the job of the liver to make some more. It does this by a process called gluconeogenesis when most of the fat burning will take place."
Gluconeogenesis (which does not use fat) is the normal recycling of glucose fragments (lactate, pyruvate and glycerol) but also is the emergency fuel supply for the brain, when liver glycogen is low, during exercise or during the night fast.
If liver glycogen is low at bedtime the brain is in mortal danger (the liver must deliver 10 grams of glucose every hour (6.5 to the brain, 3.5 to the kidneys and red blood cells) - liver capacity is 75 grams amd most people go to bed with a depleted liver for reasons above).
If the liver is not fuelled the brain (hypothalamus) activates the adrenals and cortisol degrades muscle to make glucose for the brain - this is gluconeogenesis.
During gluconeogenesis the adrenal hormones suppress the recovery hormones and fat burning is halted.
This is exactly what happens here in the west when we eat an early evening meal and we go to bed with a depleted liver, we activate stress, and not recovery biology.
It is a commonly held myth that the body can use fats during gluconeogenesis, but myth it is.
The only spare fuel for the brain is degraded muscle protein and this requires activation of the adrenals.
"But this process only kicks off when the body needs to make more blood sugar and there are no carbs or stored glycogen to burn."
If the brain were daft enough to wait for the liver to empty its glycogen store before activating adrenal biology millions would die during the night.
The brain carries 30 seconds worth of glucose at any time and is in a crisis both during the night fast and during exercise if the liver is not optimally fuelled.
Few athletes fuel their livers optimally for exercise or recovery, which is why we meet the adrenal driven diseaes in the athletic and post athletic community.
Athletes simply provide us with a speeded up version of what happens incrementally in the wider population.
The brain does and must look ahead and looking at 8 hours of the night fast with a depleted liver is bad news, recovery biology is shut down and the adrenals activated
"So feeding a high sugar
snack to a body which already has stable blood sugar will only delay this process."
Stable blood glucose is too vague a term.
The liver glycogen store may be low but blood glucose normal or in some cases even high.
If you take a measure of blood glucose at that point you will learn nothing of the underlying biology.
During exercise blood glucose may be stable as a result of muscle degradation but the picture may be false. Blood glucose is a useful tool but is a poor indicator of the underlying biology. For instance an athlete who fails to take her honey prior to bed will not recover. She will be in stress biology during the night fast. If her stress hormones are efficient, and trained athletes do possess such potential, her blood glucose may be high in the morning, at the expense of degraded muscle. When she rises, she may feel like Superwoman, and go off on a training run, a foolish enterprise indeed. Her liver is depleted. She will flood her body with more stress hormones to degrade more muscle and keep her brain going.
"With high carb dieters it may well help but I suspect not with low carbers.
This is one take on recovery biology I would like to see how you would react to this in favour of the hibernation diet?"
Low carb dieters can leave their livers in a constant state of depletion (especially if they ignore the liver fuelling foods, fruits, vegetables and honey, as is frequently the case).
They will degrade muscle and bone, and be at risk of all the adrenal driven diseases.
High carbohydrate intake, as is the case here in the west, results in hyperinsulinism and syndrome X.
They are also in a state of overactivation of the adrenals and turn all their carbs into fat via insulin.
Their liver glycogen store is permanently depleted store and they are equally at risk of all the adrenal driven diseases.
The important point in all of this is that if fat could be converted to glucose and used in the brain no person on the planet could be obese, because the brain, with its super-metabolic rate would burn fat for 24 hours a day.
But then as a species we would have no reserves during starvation and we would have perished millions of years ago.
You might carry 100 kilos of fat, but not one gram may be used in the brain.
Thank you for raising these important questions.
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