[Closed] Intermittent fasting, keto and timing of exercise

Isn't this pointless if you're only exercising?

1. Don't do a Keto diet - if you are looking at increasing Ketones in your body, don't do it. Why, I'm a Dad of a Type 1 - Keytones are a killer.

Fat etc isn't bad, sugar isn't good. As are simple carbs.

I've 'lost' 14kgs in the last 3 months due to pain meds for a knackered back (broke it riding to work when an idiot turned right into me - THREE years ago).

I put weight on as I couldn't ride as much. This year I really reduced my carbs and lost about 4kg in 5 months - nice and steady.  Couldn't cope with the pain, went on medication.  That stopped me eating, no appetite.   Not good.  Really haven't done the same miles in the last 3 months, not enough carbs, but I've shed 10kg on top. I'm now getting worried as I can't fuel a ride properly as I can't eat well.

If you are doing a 'silly diet', and that's what it is, you won't be able to ride, that's why I've not ridden as much, as I can't eat the right fuel. It's not a choice for me.

You fuel to ride.  I don't endorse any diet, just watch your carbs (ignore kcals as thats rubbish).  Carbs are key to losing weight - less, but you still need them.  You need them to ride too.

It's why, as a family with a member with Type 1 diabetes, we watch carbs.  Carbs are the key - either for dieting, or fueling a ride.  Complex (brown and whole wheat) carbs are slower release than 'white' carbs.

It's also why Type 2 (not the same disease as Type 1) is on the increase - too much white carbs.

1. Don’t do a Keto diet – if you are looking at increasing Ketones in your body, don’t do it. Why, I’m a Dad of a Type 1 – Keytones are a killer

A common misconception.

T1 diabetics are at risk of Keto Acidosis which is different from being in Ketosis which is the OP's aim

https://www.healthline.com/health/ketosis-vs-ketoacidosis

The problem with the keto diet is that it is the easiest diet to **** up, it works for those that get it right, but that is only a couple of percent of the people who do it. And when you get it wrong it really isn't a healthy diet.

I fast but i dont do it every day.. maybe 3-4 out of seven. And only for about 16-17 hours. I can train in the morning without food no problem, if i was competing or doing a really big ride i probably wouldnt do it fasted but an average 2 hour is no problem.

Keeps me lean and feeling good. 3-4 meals a day everyday is bullshit imo. Theres a lot of good evidence for fasting INTERMITTENTLY. no need to go mililtant on it.

Exercise more/eat less is sensible ?

Having not being able to eat 'properly' for about 3 months, having eaten a 'good balanced diet' before.  Match eating to exercise.

Don't diet.  Eat and exercise. Don't SNACK on foods.

A big 'issue' for us with a T1 Teen - 'oh I'll gobble 6 packets of crisps as a teen - er - you are T1 and need to take insulin - makes the rest of the family how we treat carbs....  thats how we put on weight.

PS My T1 son puts away more than twice the food I do and he does no-where near the exercise I do.  Teens.

Just giving an opinion from a family that has to watch 'food intake' to the fact we weigh it..... we don't do silly fads.

My son's condition has made me drop carbs !

PS diets - some of us need to say age... It's easer sub 35, no kids etc - bloody hard with the rest of the stuff going on...

I do this (eat in an 8 hour window) and it's fine.  One thing I've found, though, is that if I'm exercising, ie going for a proper mountain bike ride with high heart rate as opposed to riding half an hour to work, then if I haven't eaten in the 12 hours beforehand it's fine but if it's within the 12 hour window then it's best to eat before going out.  I think it's because you're not in a properly fasted state until you haven't eaten in about 12 hours.  After 12 hours I guess I'm just burning fat rather than trying to get all my energy from calories.

Did that make any sense?  I'm working nightshift at the moment which is far far more unhealthy and bad for your cognition than any diet could possibly be.

Also, don't go all religious about it.  I tend to not eat between 19:00 and 11:00 but if I'm going out for dinner or if we're having a special breakfast then I just go ahead.  No point in denying yourself if it takes away from social occasions.

Also, anyone know what the record for most consecutive days fasting is?

382 days.  Fasting won't kill you.

Also, anyone know what the record for most consecutive days fasting is?

382 days.  Fasting won’t kill you.

I suggest you read into that study a bit more.

I could read the whole thing again and try to figure out what which particular bit you're referring to.  Or maybe you could elaborate a bit?

Cryptic comments are annoying and don't really contribute much to the thread.

Ok as you failed to mention about the record in detail. The gentleman was morbidly obese, he was monitored under lab conditions to keep an eye on his health and was fed controlled amounts of supplements.

Add to that there are reported cases or fatalities part contributed to fasting and not to mention the potential general health problems due to fasting without adequate monitoring. It’s probably best you don’t make a cryptic statement of the record for fasting followed but no one ever died.

Hands up if anyone decided to fast because I said the record was 382 days.  Anyone?

I don't think you're going to die if you don't eat for 16 hours.  I also don't think you're going to die if you don't eat for 7 days.  21 days?  Maybe speak to your doctor first. If you fast for 382 days I will personally buy you a pie.

Hopefully, with fasting becoming the new fad, people will stop telling me to eat little and often throughout the day 'to keep the digestive system ticking over'.  Also, maybe they'll stop telling me I need to eat within 30 minutes of exercising or 'you won't get any benefit'.

Its only a fad diet if you go through a bunch of different diets. I guess ive been fasting this way for a number of years albeit less frequently.

Also, for me personally its not for losing weight.. i could lie on the couch all day shovelling in ginsters and fray bentos without my weight changing by more than a kilo or two. The idea that you should eat several meals a day is probably quite a recent one.

Your body does lots of positive things if you just stop shovelling stuff into it once in a while.

So where are you getting the fat to burn during exercise? If you want to go longer you still need the fuel so unless you plan to eat some fats you still won't have anything to burn bar reserves - ie losing weight unless you replenish it.

Fat takes more energy to digest than other food sources too.

 but to improve mental cognition and hopefully endurance on the bike.

What needs improving there?

This fasting / timed eating has had an inverse effect in my colleagues cognitive ability.

Obviously subjective but his concentration pre noon is not what it should be.

I do 16 / 8.

I’m quicker on my bike in the mornings before eating.

How does fasting improve mental cognition?

How does fasting improve mental cognition?

You think less about the crap things in life because you spend all your time thinking about burgers and cake !

Literally started a16:8 this morning so we shall see. Had some success with 5:2 awhile back but found it trickier to maintain so we shall see.  I found I could do a weights workout no problems on a fasted day but struggled with cycling or running.

Not sure about the mental benefits but I lost a decent chunk of flab with no real problems.

Your brain consumes 20% of the energy used by the human body. It either gets the energy it needs to function properly or it doesn't. I can't see how fasting would improve cognition. If anything, I'd have thought that fasting could potentially impair cognition, if you don't have sufficient stored energy to fuel your brain during the fasted period.

How does fasting improve mental cognition?

The amount of smugness is only rivaled by vegans, no one human could do both without imploding.

https://www.dummies.com/health/nutrition/weight-loss/improve-brain-function-and-productivity-with-fasting/

<h1>OOPS! THAT PAGE CAN’T BE FOUND.</h1>

The most text our friend has posted 😉 Maybe he is hungry

In other news I didn't have any toast before riding to work this morning, but I did on Tuesday - I feel smugger today

if you don’t have sufficient stored energy to fuel your brain during the fasted period.

The body is pretty clever in that it can convert glucose needed by the brain by non carbohydrate sources in a process called Gluconeogenesis

and the thing about fasting. Everyone fasts. Why do you think it's called 'break'fast?

Fasting can also stimulate the production of new nerve cells from stem cells in the hippocampus.  fasting stimulates the production of ketones, an energy source for neurons, and that it may also increase the number of mitochondria in neurons. Fasting also increases the number of mitochondria in nerve cells, since neurons adapt to the stress of fasting by producing more mitochondria.

A study published in the June 5 issue of Cell Stem Cell by researchers from the University of Southern California showed that cycles of prolonged fasting protect against immune system damage and, moreover, induce immune system regeneration. They concluded that fasting shifts stem cells from a dormant state to a state of self-renewal, triggering stem cell based regeneration of an organ or system (source).

and the thing about fasting. Everyone fasts. Why do you think it’s called ‘break’fast?

So where are you getting the fat to burn during exercise? If you want to go longer you still need the fuel so unless you plan to eat some fats you still won’t have anything to burn bar reserves – ie losing weight unless you replenish it.

Most people can store around 40,000 calories of fat wheras carbohydrate is around 2-2,500. If you become fat adapted you can tap into these 40,000 calories as fuel source. There are stories of ultra marathon runners doing back to back marathons on nothing but water.

I read a study where one runner had become fat adapted up to 85% of his V02max which is pretty incredible

stupid fad diet that is dangerous to your health and is promoted by charlatans.

dangerous why ?

Dangerous.  Being in ketosis damages both brain function and other body systems.  It will also screw up your metabolism leading to yo yo weight gain / loss.

but is an 8/16 diet really going to give ketosis ?

i read about someone who had good results eating 30 bananas a day.

seems about as relevent having looked at papers studying the matter of keto

although i did come across an interesting one warning of the lack of muscle adaptation using Cold water immersion for recovery during training.

Dangerous.  Being in ketosis damages both brain function and other body systems.  It will also screw up your metabolism leading to yo yo weight gain / loss.

Think we better get those mums to stop breastfeeding their babies. It's too dangerous!!!

be good to see some research to back up your wild claims TJ

Dead easy just post a random YouTube video TJ.

It seems there’s a such a bit thing about fasting an a Keto diet. Turns out most on here have found out you don’t eat when sleeping. Who knew?

breastfeeding does not lead to ketosis.

8/16 will not lead to ketosis

If you are ketosis you are in a dangerous metabolic state

I suggest you look into some basic physiology.

High fat / high meat diets contain their own dangers

Lots of pseudo science around this.  Most of it utter bollox.  Have a read round the peer reviewed literature for the dangers including increased risk of cardivascular disease, insulin resistance, non alchol fatty liver disease and that the weight loss effects like with all fad diets are only temporary.

OBJECTIVE: To determine whether ketogenic weight reducing diets have adverse effects on cognitive performance. SUBJECTS: 21 overweight women (mean BMI = 41 kg/m2). DESIGN: Randomized double-blinded study. METHOD: Subjects were randomized to ketogenic or nonketogenic liquid formula very low energy diets, that were comparable in energy and in protein content. Subjects remained on the diet for 28 days and were reevaluated periodically with brief measures of cognitive performance assessing attention and mental flexibility. RESULTS: Weight losses were comparable on the two diets (Mean = 8.1 kg). Performance on attention tasks did not differ as a function of the diet. However, performance on the trail making task, a neuropsychological test that requires higher order mental processing and flexibility, was adversely affected by the ketogenic diet. The worsening in performance was observed primarily between baseline and week one of the ketogenic diet. CONCLUSIONS: Further research is needed to confirm this finding and to determine whether ketogenic diets negatively affect other complex mental tasks, such as problem solving.

https://europepmc.org/abstract/med/8589783/reload=0

And lots of other good peer reviewed evidence of other serious adverse effects from it.

As far as I can see from a literature search there is good evidence its not better for weight loss than a "eat less move more"  There is good evidence for loads of serious adverse effects including increased risk of cardiovascular disease.

I like evidence based approach to health.  The evidence on keto diets is not great but what there is shows positive benefits are few and adverse effects are common.

Much of what people are saying they do on this thread will not put you into ketosis anyway -

Have a wee search around the credible peer reviewed bits of research.  Don't believe a word chalatans say.  Base your actions around the evidence

It is used and does woirk in controlling otherwise intractable epilepsy in children.  However this is associated with increased cardiovascular risk
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<p id="simple-para0015">The ketogenic diet is a high-fat, low-carbohydrate, adequate-protein diet that is used to decrease the frequency of seizures in patients who have refractory epilepsy. Despite its positive effects in some patients, there are potential adverse effects. Two complications related to the ketogenic diet are selenium deficiency, which has been associated with impaired myocardial function, and QT prolongation as documented on electrocardiography. Reported here are two cases of death in a child on the ketogenic diet for seizure control. In case 1, the child who died of complications related to torsade de pointes, with documented QT prolongation; post mortem examination revealed selenium-deficiency cardiomyopathy. In case 2, a child experienced QT prolongation while on the ketogenic diet and later died suddenly at home. Both children exhibited selenium deficiency. These two cases suggest that patients on the ketogenic diet require monitoring of the QT interval by electrocardiography, myocardial function by echocardiography, and selenium levels before and during the ketogenic diet.</p>

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https://www.sciencedirect.com/science/article/pii/S0887899408003998

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The nutrient adequacy of the currently used KD has not been fully evaluated. The nutrient content of KD with usual supplements may not meet Recommended Dietary Allowances (RDA) for selenium and may not provide other trace minerals in adequate amounts. At our center, selenium deficiency was found in 20% of the patients evaluated. Screening for selenium deficiency is suggested if the patient KD regimen does not meet ≥75% of the RDA or if the child is symptomatic. Nutrient supplementation should provide adequate trace elements for children treated with the KD. The KD requires close monitoring of the overall nutritional status.

https://onlinelibrary.wiley.com/doi/abs/10.1046/j.1528-1157.2003.26102.x

Enough?

Much of what people are saying they do on this thread will not put you into ketosis anyway –

They’re skipping breakfast and not eating in the evening. Sounds like they’re well errmmm how do break this to them? Eating less moving more.

I've no idea what ketosis is, but I've been doing 16/8 by the cheaty don't eat breakfast route for a few weeks now and have had positive results. Mentally it's the easiest way to remove a few calories (would have been boiled or scrambled eggs normally, down to 1 slice of toast or Ryvita) for me, and I suspect its this rather than timing thats working - just stay sensible through till 8pm then stop.

Mainly running at present and having less in me helps - plenty of glycogen in there for an hour or so running.

So if I eat my breakfast after 8am and finish my dinner before 4pm, I will get a "fasting effect", but if I eat my breakfast at 7am and finish my dinner at 5pm, nothing special happens?