The purpose of Ketones

robertw486

I'm hoping more of the keto informed crowd will input here. I think I know just enough to be dangerous with assumptions.

But from my understanding most of us have the ability at some point to get the energy from ketones without going really low carb or dietary ketosis. I've been reading up on some of the keto adapted endurance athletes who essentially use the ketone levels much like those of us on a conventional diet might few glycogen levels. And from what I'm reading, they can also somewhat carb load (relative to their diet) and as such pull energy from both systems fairly well on longer events.

And I think some of the differences in RER/RQ at below ketosis diet levels are influenced by ketones, which explains some of the differences person to person.



But I'd like to point out that the "no going back" theory is just scientific woo IMO. Switching from low carb or keto back to a conventional diet would likely replenish glycogen and include some weight shift, but as with any eating type the threat of any long term weight gain, maintenance, or loss still boils down to energy balance. If anyone is claiming keto somehow "breaks" the reality of CICO long term, I'm open to scientific studies stating so.

coreyreichle

lithezebra wrote: »

eric_sg61 wrote: »

GaleHawkins wrote: »

eric_sg61 wrote: »

dpwellman wrote: »

stevencloser wrote: »

During ketosis, the liver has to use the stuff that is necessary to do this for gluconeogenesis though, so it instead creates Ketones out of the Acetyl-CoA. But it looks like the only way Ketones can be used to get energy is to get turned back to Acetyl-CoA, so what exactly are the Ketones good for then if they need to get turned back into what it was before?

That is correct. They're good for when glucose is unavailable. As long as one's liver is healthy and otherwise under-taxed, keytones can be used as energy in a "pinch"

The following applies to otherwise healthy individuals

So why do people (in the pursuit of weight loss) try to force ketosis? Because it has very rapid initial "gains" towards the goal of weight loss, but it still remains a sub-optimal strategy. Firstly, all things being equal, the fat-loss delta between low-carb and low fat diets disappears in 12 to 18 months. That delta is relevant because following long term low-carb, there remains a "no going back" threshold where the re-introduction of carbohydrates to a normal level will very likely lead to rapid fat gain. Secondly, just because your brain and muscles can use keytones doesn't mean that they "want" to. Glucose is always the "preferred" energy source. Mental acuity and muscular endurance suffer when glucose is not available. I'm thinking specifically of a twin study done in UK (I think) that tested that hypothesis and their results support it. Lastly, low-carb diets consequently tend to be high in fat-- of particular concern, saturated fat. Again, as stated previously, carb restriction has very rapid initial results, however long term adherence mortgages future cardiovascular health in pursuit of those results.

It remains that in either strategy, neither the low carb lost weight (excess fat) solely because he was low carb. Nor did the low fat lose weight solely because low-fat, but because of a calorie deficit.

Best bet for long term: fruits, vegetables, some whole grains here and there, and avoid high concentrations of simple sugars and saturated fats.

This is where people who folllow low carb gurus are going to pay a heavy price.

Well at least we know the inputs come from people who had not experienced the keto eating life style.

While I did not go LCHF to lose weight the weight loss was an accident that took place. After keto cured my cravings the weight came off without having to count calories in my case.

Plenty of people have tried low carb/keto and paid the piper
https://www.facebook.com/180degreehealth/posts/1193989860629357

That's an opinion piece, offering no citations, not only an opinion piece, but one intended to sell books. Do you have peer-reviewed studies that support the assertion that months or years of not eating carbs will cause "insomnia, low energy levels, depression, dry skin, constipation, sexual apathy, and so on?"

Dude is selling books on how to raise your metabolic rate: http://www.amazon.com/Matt-Stone/e/B001KIM1IA/?_encoding=UTF8&camp=1789&creative=390957&linkCode=ur2&tag=180degr-20

There are numerous studies. One such is here: http://www.nature.com/pr/journal/v55/n3/full/pr200478a.html

It comes from the fact that while our brains can function on ketones (And, often do at night), it's not the optimal fuel: Glucose is. Your brain can function suboptimally for a while, and ketone burning has some neuroprotective effect, especially during hypoxia. But, if you want optimal function, you need to provide optimal fuel.

Ketosis also causes athletic performance to suffer. Initially, during the transition to ketosis adaptation, many individuals suffer from "keto flu", in which you feel like you have the flu, and all athletic performance tanks. Eventually, you return to "somewhat" normal performance, minus the sprinting capacity.

So, for endurance athletes, looking to win races, ketosis is probably not the best idea. Yes, I know one marathon runner won a couple of marathons, and he does keto. I get it, one runner was able to pull it off. However, for most individuals, carb loading the day before is the way to go, and providing a more tuned macro set is advisable.

yarwell

Ketones are used by the brain and other parts of the body as a fuel when available, and uptake generally rises with concentration in the blood.

Ketones co-exist with glucose, at least in the living. Keto dieters have fasting blood glucose levels similar to healthy carb eaters but their daily average or AUC will be lower. Even the therapeutic applications of keto aim for G/K ratios close to 1 but higher levels up to 10 are seen in dieters.

There's some evidence that long term fasted keto - adapted people can run lower blood glucose without symptoms of hypoglycaemia.

I'm not clear what the control mechanism is, but ketone production seems to require low levels of liver glycogen and reduced supply of competing substrates like protein / amino acids.

lisawinning4losing

10 proven health benefits of low carb and ketogenic diets (with citations).

https://authoritynutrition.com/10-benefits-of-low-carb-ketogenic-diets/

For anyone who's curious. I've noticed that in the LCHF group, there are a lot of people who are there not just for weight loss but for medical reasons, who have had a lot of success. It's just one option that's available to people. It might not be right for everyone, but it works well for some.