Your views on 'CARBOHYDRATES'

Sidesteal

Why? They are an imporant part of a heatlhy diet so why does it matter if people think carbs are essential to life?

Because they could then go on to misinform someone else about what they think is an absolute necessity.

grinch031

Carbohydrates are the spawn of satan.

Carbs are in everything you eat more or less. We need carbs for our brain to function. Just be smart about what carbs you eat ie vegetables over highly processed bread.

Carbs FTW!

In the absence of carbs, our brains can run just fine on ketones.

Your brain generally never runs on ketones. It conserves every bit of glucose it can from your body, from the few carbs you actually eat (used directly by the brain) to converting protein to glucose using gluconeogenesis, using either protein you've eaten, or by breaking down muscle tissue to get protein to convert. Only in true starvation will your brain start utilizing ketones for energy.

Can you define "true starvation"?

Yes, that means not eating anything at all. It takes several days of complete fasting (no food at all) in order for your brain to start switching over to ketones. It will continue to use glucose as long as glucose is readily available from carbs or protein, but as soon as food runs out completely, it will conserve glucose for emergency use, and start running on ketones. Even then, it's only about 75% ketones and 25% glucose, the brain will absolutely never run on 100% ketones, as it's incredibly inefficient and seriously compromises cognitive ability. It's pretty much enough to keep you functional, glucose is required for normal full brain function.

What is your source of information for this that the brain won't switch over to ketones unless you stop eating?

tigersword

http://www.ncbi.nlm.nih.gov/pubmed/8263048

There ya go, it takes roughly 3.5 days of starvation before the brain starts burning ketones.

bcattoes

Why? They are an imporant part of a heatlhy diet so why does it matter if people think carbs are essential to life?

Because they could then go on to misinform someone else about what they think is an absolute necessity.

Yes, that's true. But of the misinformation propogated on this site, this is likely the least harmful.

grinch031

http://www.ncbi.nlm.nih.gov/pubmed/8263048

There ya go, it takes roughly 3.5 days of starvation before the brain starts burning ketones.

This doesn't say anything about what happens on a ketogenic diet where you aren't starving.

tigersword

What do you think gluconeogenesis is actually for? Do you think the liver converts protein and fat into glucose just for fun, while forcing the brain to run of ketones? As has been stated many times already in this thread, the body can generate all the glucose it needs from whatever food you eat. The brain is what needs glucose, the rest of the body can run (albeit very inefficiently) on ketones and fat. That's why it takes over 3 days of complete starvation before the brain even starts using ketones, because it's run out of stored food, and exhausted the majority of the glycogen supply, thereby forcing the brain to conserve what little glycogen is left, and use ketones to make up the difference.

grinch031

What do you think gluconeogenesis is actually for? Do you think the liver converts protein and fat into glucose just for fun, while forcing the brain to run of ketones? As has been stated many times already in this thread, the body can generate all the glucose it needs from whatever food you eat. The brain is what needs glucose, the rest of the body can run (albeit very inefficiently) on ketones and fat. That's why it takes over 3 days of complete starvation before the brain even starts using ketones, because it's run out of stored food, and exhausted the majority of the glycogen supply, thereby forcing the brain to conserve what little glycogen is left, and use ketones to make up the difference.

Gluconeogenesis is required to ensure at least 25% of the brain's fuel comes from glucose. And because it takes several days to adapt to a ketogenic diet, gluconeogenesis will convert more protein into glucose until the brain adapts to using ketones. So it makes no difference whether you are in starvation or whether you are simply on a ketogenic diet. What matters is how many carbs and how much protein you eat as to how much gluconeogenesis needs to occur. So if you eat too much protein, then certainly you won't be fueling your brain with ketones.

bcattoes

OMG, I love these carb threads! So much passion and science and misinformation. But all that aside, I really can't imagine why anyone would want to live without carbs, even if a body can function without them.

HardcorePork

OMG, I love these carb threads! So much passion and science and misinformation. But all that aside, I really can't imagine why anyone would want to live without carbs, even if a body can function without them.

I've come to realize that some people NEED a certain amount of fanaticism in order to adhere to their goals. If they cling to a belief with a death grip, it somehow solidifies their commitment to health and wellness. I don't get it...but I have always been thin and LOVED healthy food and exercise. I can't put myself in their shoes...

tigersword

What do you think gluconeogenesis is actually for? Do you think the liver converts protein and fat into glucose just for fun, while forcing the brain to run of ketones? As has been stated many times already in this thread, the body can generate all the glucose it needs from whatever food you eat. The brain is what needs glucose, the rest of the body can run (albeit very inefficiently) on ketones and fat. That's why it takes over 3 days of complete starvation before the brain even starts using ketones, because it's run out of stored food, and exhausted the majority of the glycogen supply, thereby forcing the brain to conserve what little glycogen is left, and use ketones to make up the difference.

Gluconeogenesis is required to ensure at least 25% of the brain's fuel comes from glucose. And because it takes several days to adapt to a ketogenic diet, gluconeogenesis will convert more protein into glucose until the brain adapts to using ketones. So it makes no difference whether you are in starvation or whether you are simply on a ketogenic diet. What matters is how many carbs and how much protein you eat as to how much gluconeogenesis needs to occur. So if you eat too much protein, then certainly you won't be fueling your brain with ketones.

Gluconeogenesis also converts fat into glucose, not just protein, so you'd need to cut back on everything to get gluconeogenesis to not happen.

grinch031

What do you think gluconeogenesis is actually for? Do you think the liver converts protein and fat into glucose just for fun, while forcing the brain to run of ketones? As has been stated many times already in this thread, the body can generate all the glucose it needs from whatever food you eat. The brain is what needs glucose, the rest of the body can run (albeit very inefficiently) on ketones and fat. That's why it takes over 3 days of complete starvation before the brain even starts using ketones, because it's run out of stored food, and exhausted the majority of the glycogen supply, thereby forcing the brain to conserve what little glycogen is left, and use ketones to make up the difference.

Gluconeogenesis is required to ensure at least 25% of the brain's fuel comes from glucose. And because it takes several days to adapt to a ketogenic diet, gluconeogenesis will convert more protein into glucose until the brain adapts to using ketones. So it makes no difference whether you are in starvation or whether you are simply on a ketogenic diet. What matters is how many carbs and how much protein you eat as to how much gluconeogenesis needs to occur. So if you eat too much protein, then certainly you won't be fueling your brain with ketones.

Gluconeogenesis also converts fat into glucose, not just protein, so you'd need to cut back on everything to get gluconeogenesis to not happen.

I can't speak much for fat other than to say its highly inefficient to convert to glucose and the brain is still going to prefer ketones once they are readily available. Carb intake is most important followed by protein intake. There are plenty of endurance athletes on ketogenic diets and if what you say is true, they would all have no muscle left. They intentionally eat only moderate amounts of protein as to keep themselves in ketosis and avoid too much gluconeogenesis.

tigersword

Gluconeogenesis doesn't cancel out ketosis. They are separate metabolic activities. Gluconeogenesis only creates enough glucose to power the brain and control blood glucose, it does not replenish glycogen stores, so the rest of the body is still running on fat and ketones.

davidlbass

Love my carbs. I just count calories.

Wayne092

So.....do I eat spaghetti or not? I really don't know.

grinch031

Gluconeogenesis doesn't cancel out ketosis. They are separate metabolic activities. Gluconeogenesis only creates enough glucose to power the brain and control blood glucose, it does not replenish glycogen stores, so the rest of the body is still running on fat and ketones.

The only thing I'm really trying to suggest you are wrong about is that the brain isn't fueled by ketones when the person consumes adequate calories. Ketones will fulfill up to 75% of the brain's fuel requirements as long as 1) carb intake is low and 2) protein intake is low to moderate. Whether you are in starvation or not doesn't matter.