If you want to fast, do it the best possible way (Don’t fight Cortisol)

#Keto_coach_Jack ‘s Sciency Thoughts

#PublicServiceAnnouncement – This post is about fasting and a new method of fasting. If what you are currently doing is working for you and you are happy, please don’t change it. If you want to try something different that may suit you better and may yield better results, please keep reading.

Fasting: Could there be a better way?

One of the most talked about topics in the keto world today is fasting or intermittent fasting (IF). There are definitely some well documented benefits to fasting, but there is more to the story than meets the eye and it is not a simple one-size-fits-all approach. I will get to the possible better way but you’ll have to be patient. I like to be detailed. Patience is a virtue.

In order to bring this all into context, I have to talk about a very important hormone and it’s one that often gets a bad rap. I’m talking about cortisol. People call it the stress hormone and, because it’s associated with stress, they assume it’s bad. It is actually very vital and when it doesn’t work properly it can put you in real danger.

One of cortisol’s primary purposes is to get a burst of energy into the system when it is needed, like when you’re being chased by a bear or getting through a very tough workout. This is sometimes referred to as the “fight or flight” response. How it accomplishes this, at least in the keto adapted person, is by telling the liver to pump glucose into the blood through gluconeogenesis (creation of new glucose either from glycerol from fat or from amino acids from protein). Now that I have brought cortisol into the fold, I will get into the whole mess of how it links to fasting and how we may be able to do it better. Remember how I said patience is a virtue? You need it with me. I’m long winded.

OK. Here is the meat of it all: Cortisol has a natural rhythm and response. It spikes at given times and for a certain reason. At least, for a hormonally balanced individual it does. The first time of day it spikes is as soon as you wake up. It does this to help you wake up and have energy to start your day, and then tapers off and becomes lowest at night so you can go to sleep. If cortisol spikes first thing in the morning, this means we have higher blood sugar in the morning. If we have higher blood sugar we also will have higher insulin.

Fasting is characterized by having consistently low blood sugar and therefore low insulin. If we fast from 7pm until noon the next day, when cortisol spikes in the morning (and then spikes blood sugar and insulin), technically we are physiologically breaking the fast when we wake up and not actually fasting for a full 17 hours as intended.

If your blood sugar and, in turn, insulin is spiked in the morning anyway, wouldn’t it be pertinent to take advantage of that natural spike by eating a nice breakfast and having the insulin clear all of the energy at the same time? You aren’t technically fasting anymore anyway, so eating at this time will be taking advantage of the already high insulin response and could open up a better way to fast. If your natural cortisol rhythm is high in the morning and tapers off throughout the day, maybe it would be better to fast from the afternoon until the natural cortisol spike in the morning. Hormonally speaking, this seems like the most metabolically sound method. Would this not better manage insulin and therefore make for a better fasting experience? I think so.

So here is my theory:

The typical fasting method is fasting from say 7pm until 12pm the next day. This is 17 hours, but if you wake at 7am, you are spiking your cortisol and thus insulin and therefore are physiologically breaking your fast. Essentially you are fasting from 7pm until 7am. This is only 12 hours rather than the 17 that was originally intended.

#keto_coach_Jack ’s approach would be this:

Fast from 2pm until you wake up the following day. Say that is 7am. Providing you don’t work out or get chased by a bear in that time frame, you will have a full 17 hour fast. Eat when you wake up and take advantage of that already spiked insulin.

#IfitAintBrokeDontFixit – Again, if you are happy with the traditional way you are fasting, keep doing it! If you are curious to see if there may be a better way for you, please feel free to try this. Am I guaranteeing that this will work wonders? There are no guarantees. Its just my sciency thoughts.


If you would like help with your Ketogenic Diet you can sign up for personal coaching with Coach Jack. For more information, to read client testimonials or to get in touch with Jack visit:

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54 Replies to “If you want to fast, do it the best possible way (Don’t fight Cortisol)”

  1. I respectfully disagree that our bodies are physiologically breaking the fast. I feel the keto community misinterprets the word fast in a couple ways.

    Fasting is to refrain from food consumption. If what you explain is true, people could not go on extended day fasts. Yes our hormones are designed to wake us up and use what our bodies already have in them to do so, and yes it is beneficial to break an overnight fast by eating soon after waking, but the body process is not a physiologic breaking of a fast. If you don’t eat, you don’t break the fast.

    Also, a lot of people in the keto community as a whole discuss an egg fast to break a stall. It is not an egg fast. It is an egg challenge. If it was an egg fast, people should abstain from eating eggs.

    1. I am glad you respectfully disagree. That is your prerogative. The community misinterprets many things. I am not the typical part of the community and I can 100% assure you that I am not misinterpreting this. You are talking theology and I am talking human physiology.

      The theological definition of fasting is to refrain from eating. This is the human definition like the religious definition of fasting. This is not the physiological function of fasting.

      Just not eating is not what actually causes a fast to have its metabolic effects. The reason for the fast works the way it does is hormonal and the major driver is insulin. Read and watch the work of Dr. Fung. He explains it pretty clearly. Not eating surely keeps insulin low. Until the cortisol spike of the dawn effect. This is a very powerful response that raises blood sugar fairly dramatically. What happens when blood sugar rises? Insulin response. When you get an insulin response you stop allowing fat to be released from fat stores.

      Fasting by physiological definition – state of low insulin allowing fat to be released from fat stores

      Dawn effect raises insulin stopping fat from being released – Fast broken by definition.

      By your human perspective you disagree as you see fasting as just not eating but it is much more than that, it is a hormonal response and that response does not care if you believe it or not.

      You can still go on a multi-day fast. It just isn’t actually more than a 24 hour fast. It is multiple 24 hour fasts and technically these people are losing small amounts of lean mass every morning when their cortisol prompts gluconeogenesis. They would likely have the identical effects of the multi-day fast, in regards to fat loss, if they would consume 20g protein and 60g of fat each morning for breakfast but they would have a net zero lean mass loss since 20g protein in the breakfast will replace the 20g we turnover daily from the GNG.

      Even Dr. Fung says you can have fat during a fast as it doesn’t spike insulin.

      Yes we understand an egg fast is not really a egg fast and a water fast is not a water fast and a fat fast is not really a fat fast. We clearly understand this basic definition. It is a simple term that is used to describe a restrictive plan that includes eating only one thing and is called this for simplicity terms. You are not stating some amazing finding that nobody knows. This is common knowledge an EVERYONE understands this.

      What is easier to understand:

      “I am doing an egg fast”


      “I am doing an egg challenge”

      Nobody would know what the hell you are talking about if you said I am doing an egg challenge then an entire conversation would ensue. When you say “egg fast” everyone understands. Life is not about being 100% literally accurate. It is about getting a message across.

      1. I’ve been doing Keto approximately 4 weeks.
        The instructions I’ve been given and follow is:
        Bullet Proof coffee upon rising in the am. Then don’t eat until you are hungry. Drink another BPC at the first sign of hunger. Then eat a ketogenic meal the next time you have hunger pangs.
        Bullet Proof Coffee (BPC)
        1 tbsp butter
        2 tbsp coconut oil
        2 tbsp heavy cream 35%
        1 cup of coffee with caffeine
        Dash of Stevia

        I find I have a ‘fuzzy’ head or minor headache for several hours most of the morning.
        Do you think I would feel better if I had breakfast?

        1. You would 100% feel better. We are wired to eat in the morning. I would also increase your intake of the vital electrolytes. 1-1.5 tsp of sea salt per day split into 3-4 doses. 400mg magnesium per day taken at night before bed is ideal. 200mg chelated potassium to start with and see how you feel.

          1. Thank you for your response.
            I plan on implementing your suggestions.

            I’m a newbie and haven’t worked my way through a lot of info. Would you direct me to a link that speaks to meal plans?

          2. I dont believe in meal plans. They teach you how to eat what someone tells you to eat. You need to learn how to build out your own meals plans rather than someone telling you what to eat.

            Give a man a fish and he eats for a day. Teach a man to fish and he eats forever.

        2. I have something tovsay.. wenever i took stevia i had a heavy head and fussy day thruout. Wen i cut stevia completely now i am ok.. so get rid of stevia and see coz i read stevia has side effects on some..

      2. Well sometimes it would be better to state things properly. A fast is a fast. Period. Anything you eat or drink that puts metabolism to work is ending a fast. I am no genius. In fact I am a slow learner. So I thing we could all make the little effort it takes and say challenge instead of fasting, because it is WRONG to say it otherwise. In fact the few people that differenciate one word from thenother actually may get confused when reading this big mistakes. So let’s upgrade ourselves into a better understanding of what it os intended to communicate and let’s get that message across as it shouls, by people understanding the difference.

        1. There are different definitions and meaning of fasts.

          Theological definition – Consuming nothing at all. This is usually for religion.

          Metabolic definition – low insulin levels allowing glucagon to be high which prompts release of fatty acids and ketone prodution

          I use the metabolic definition and is the only thing I care about. I could not care less about the theological term fast. The only thing I care about is the biochemical function of a fast and how that relates to metabolism and weight loss. In this way of fasting you keep insulin low and lose weight because of it. This is can be maintained with eating fat only because it has no impact on insulin levels and is broken by anything that raises insulin such as a cortisol spike.

  2. Wow! Jack! That is one of the most clarifying posts I have ever read. Even your response to the first post. Thank you so much. What you are saying makes so much sense to me. Keep it up please.

    1. I am glad you enjoyed it. I try to make everything make as much sense as possible. If people cannot relate to it, it probably wont have any impact right. 🙂

      1. I’m going to try to implement this new strategy, thanks for the info.

        I know you’re more focused on Keto that fasting but I’d love to read your explanation of the different mechanisms involved in energy restriction vs fasting and how they contrast.

        1. Energy restriction causes the body to energy restrict. Very straight forward. I don’t think extended periods of fasting are any different from long term caloric restriction.

          In caloric restriction the body learns a budget and works with it. It knows a limited amount of food is coming in and learns how to work with it so it can save fat stores for a true actual absense of incoming energy.

          In short term fasting, like 24 hours, the body dies exactly as would be expected and takes the deficit from fat. Now if you make this fast 7 days, by day 7 you are going to see some reduction in metabolic rate I am sure. The body is going to see that there is a energy shortage and is not going to want to keep expending at the same rate. If it did there would be real danger of running out of fuel and dying. This is only logical. The body is very smart and very good at energy management. It is not going to keep ripping through 2500 cals of fat a day if it sees a pattern of none coming in. The main goal of the body is life and preservation of it. In order to protect the longevity it will not just utilize all of its fat stores at a constant rate. That would mean a faster death.

          This is why I think more frequent shorter fasting periods are fat more beneficial than longer term fasts.

          1. Phinney and Volek are brilliant. They still have the trappings of scientists which tends to make them lose commons sense. There is very little actual human data that shows the levels of lean mass loss that they are stating. You cannot directly correlate nitrogen loss to lean tissue loss. it has actually been shown that the actual turnover of protein per day is roughly 20g in the average male. That would not equate to a lb a day as they suggest. I’ve done 5 day fasts before and measure lean mass daily via advanced BIA measure and it showed little to no lean mass loss on any of the times I did this. The largest loss I saw was was 0.6lbs after 5 days. I do believe Dr. Jason Fung would have similar data as he has done extended fasts with thousands of people.

            What they are missing is the fact that we do store amino acids. We also recycle 60-70% of the amino acids that we require daily leaving only 30-40% to replenish the turnover. These can come from the amino acid pools leaving very little to come from lean mass. We also have an amazing ability to convert various amino acids from one form to another if we dont have one in the system that we need. There are many mechanisms at play to prevent the type of lean mass losses they are inferring. I would love to see Jason Fung’s rebuttle to this. I am sure he would rip it apart. he would not fast people for 21 days if they lost 1/4 of lean mass a day. After 30 days the total weight loss in a person would be 1/2 lb per day so he is saying that 1/4 lb of that is lean mass and 1/4 lb is fat. That is highly unlikely.

            I do agree that longer than a 24 hour fast has draw backs. There is more to the story than lean tissue loss. There is adrenal fatigue and vitamin/mineral deficiencies to account for. I think those are the more serious issues than lean tissue losses. I am alos in complete agreement that the base metabolic rate would drop after consecutive days of fasting. I dont see how it couldn’t.

            Just an example of how they cannot be right:

            The longest fast in medical history is 382 days. This man ate nothing for over a year. If their thought was right, he would have lost 10 lbs of lean tissue in the first 30 days then 1/4 lb per day every day after that.

            That would work out to a total of 98lbs of lean tissue lost.

            This man weighed 456 lbs on day one. He would have like had a lean mass weight, being generous, of 180lbs. According to Phinney and Volek he would have been left with 80lbs of lean mass at the end of this. Not bloodly likely. His ending weight was 180lbs and 5 years post he was still 196lbs. If he was actually reduced to 80lbs of lean mass he would not have been able to hold his 180 lbs upright from frailty. they don’t specifically talk about the lean mass losses in the study but it only stands to reason they would have noted this as a result if it was as dramatic as Phinney tries to say.

            382 day fast

            In this study they speak of the downregulation of Gluconeogenesis and how lean mass is preserved while fasting.

            Effects of long term fasting

            Here is some data from Jason Fung on fasting and lean tissue loss.

            Fung on muscle loss

  3. Hi Jack would this woe work well with someone who is a type 2 diabetic?? Ive been doing mostly 16/8 fasts a few times a wk with the rest sometimes an hr or two more or less the rest of the time. Ive started this because of being diabetic, but I want to get it right so as not to mess my metabolism up even more than it already is.

    1. I work with several Type 2s and they have all been able to successfully get their blood glucose to a normal range and even been able to reduce their medications with the help of their doctors. This is the best possible woe for a type 2.

  4. Jack, I am hypothyroid and I take synthetic T4 when I first wake and then synthetic T3 a half hour later. I’ve been instructed by my doctors to wait to eat until a half hour after taking my meds. I have been curious how this effects my ability to take advantage of eating during the natural spike if I have to wait an hour to eat in the morning?

    1. YOu have to do what you have to do. Just take your meds as soon as you get up and eat as soon as you can after.

  5. Is fasting from 2pm to 7am the same as the “breakfast to breakfast” fast?
    Do you eat your TDEE before beginning the fast?

    1. Is it light out before 2pm where you live? If not, no it is the opposite of a breakfast to breakfast fast. Light sets your circadian rhythm which prompts digestion and prompts a release of cortisol to wake you up for the day. A breakfast to breakfast fast takes place from morning cortisol spike to morning cortisol spike only. At no other time does a fast matter.

  6. A couple of quick questions: How long is the natural spike every morning, on average? Regardless of fasting, is the bottom line you are not using the ketone metabolic pathway (losing fat) during this spike?

    1. The spike is different for everyone.

      You are making and using glucose during this spike and it is coming from lean mass and a bit of glycerol from fat. You will not be using ketones during this period.

  7. What will a fasted crossfit workout do to cortisol and insulin. I wake at 5:00 am. Train at 6:00 till 7:00. Then usually eat at 9:00-9:30 ish

    1. It will do the same thing as a non fasted crossfit workout if you are low carb. Likely if you arent low carb you may get a similar result depending on how much carbs you have had and what the workout is.

      If you are low carb wether fasted or not You hit it hard and the workouts are typically glycolytic, they need glucose, so the blood sugar drops causing cortisol to spike to get glucagon going. Gluconeogenesis ramps up and blood sugar rises to meet the need. After the workout is done it takes time for the process to ramp down and you will have high blood glucose. This will spike insulin to clear it and it will be loaded into muscles as glycogen. Your body will use these for fuel for the better part of the day but insulin will drop quickly and you will go back to fat release as well.

  8. In my situation, I work 7pm-7am and have gotten used to staying up all night and sleeping during the day. I usually wake up about 4pm. Would the dawn effect still happen for me in the morning sometime or would it happen when I wake up in the evening? 🤔

    1. That is hard to say. It is primarily connected to the dialy light dark cycles but staying up all night may have an impact on this. There are cortisol pattern tests you can have done to determine this.

  9. So following the logic in the above post and other references to natural day light, if I wake up at 4:30 AM even if I am exposed to LED lighting when I arrived at work at 6 AM, cortisol release wouldn’t really occur for me until sunrise?

    1. It depends on the light. As far as I know it is UV exposure that activates the receptors in the eyes to start the clock.

  10. Very helpful. As a long-time obese woman, I have been following Dr Fung’s recommendations for lowering insulin through fasting, and have found it easy – a ten day extended fast in January for example. I drink bone broth and coffee during fasts. I feel great. But there has been little or no weight loss. I get that lowering insulin permanently is a long term goal, as is repairing damaged metabolism by eating my full TDEE. I am gaining weight eating my full TDEE (been doing it for five days now) and registering very low ketone levels, compared to when I fast. Is it too soon to try building a fast into the TDEE approach?

    1. you have to give your metabolism a chance to repair. You should not consider doing ay changes until you have stopped gaining weight and potentially until you have started losing at TDEE..

      What if you gain on TDEE

  11. Fair enough and thank you.

    Also, based upon what you have written about fat loss being primarily about glycogen release rather than CICO, then if I followed the CS Keto regimen strictly at TDEE, compared to IF (whether on a 16/8 regimen or 2-3x 24 hour fasts per week) in conjunction with CS Keto to TDEE during the 8 hour feedings periods or on the non-fasting days, would I lose weight at the same pace?

    Trying to figure out if I should just ditch fasting for a while or not.

    Main aim is to get to 170-180. I’m 5’ 10” 230, very similar body build to you (plenty of muscle under all my excess fat).

    1. That is impossible to know. Everyone reacts slightly differently based on their level of metabolic damage.

  12. I loved your article and the fact that you took much time and detail to explain the process. I am wanting to learn from your experience and knowledge to find answers to my personal weight loss dilemmas.

    I have been very curious about the morning phenomena/Somogyi effect as I feel this was a big part of my diabetes while pregnant. I would wake up at 7 am with blood sugar levels over 130 with my last meal being at 7pm. A nutritionist told me to eat something before bed such as an apple, a small bowl of ice cream or peanut butter crackers right before going to sleep. Whenever I followed this advice, I would wake up with blood sugar at 80-90. This would show that I was spiking at night and having something before bed sustained my body.

    Currently, I’m 46 yrs of age trying to loose weight through keto from a weight gain increased from steroid treatments. I don’t have a gall bladder and I’m no longer diabetic, but didn’t lose weight other than 15 lbs water weight the first 3 months doing strick keto… No cheating, no sugar subs…etc. I was fasting 4-5 days a week 7pm-1pm. It s becoming discouraging, but I enjoyed the other benefits of keto and kept going (off pain meds, better sleep, more energy).

    I then remembered my time being pregnant and changed up my fasting times from 10pm – 3/4pm. My last food being a snack at bedtime like I did when pregnant (except keto-usually a serving pecans with MCT oil and a spray of HWC). This seems to have broken my stall and after 4 days I dropped 6 lbs after almost a 3 month stall. Since continuing this I’m losing 1-1.5 lbs/week.

    My question is, should I continue doing this or change the times as you have suggested? An I doing something right/wrong or is this weight loss coincidental? I want to loose weight the healthiest way possible. I have read some studies that support a snack before bed for those who spike in early morning hours….. But none were doing Keto.

    I also seem to spike in my past when I am exercising such as running…. I get shakes and become nauseous if I don’t eat a carb and protein before exercising. I’m currently not doing any exercise other than walking while on keto… due to some physical injuries (steroid treatment for broken ankle and torn labrum in shoulder).

    Thank you in advance for your time and thoughts. Our bodies seem to be it’s own unique chemistry set. Trying to absorb all this new information and tweak it to our own bodies can be overwhelming with so many different variables. Thanks again.

    1. If what you are doing is working for you tehn keep doing it until it doesnt. The optimal process for fasting is not skipping breakfst. Eating with the correct circadian rhytym has immense benefits to everything from weight loss to insulin sensitivity. Exercising can be a huge confounder with weight loss. I never recommend any type of intense exercise when losing weight. Walking or very light cardio keeping heart rate to below 120 bpm for fat loss then after you have lost hte weight high intensity has many otehr benefits but will not hinder losses.

  13. So what would be a proper “eating window” for those of us that work nights and sleep during the day?

    I work 6pm-6am, so I generally sleep from 7/8am-2/3pm.

    Thank you!

    1. I would eat at 7/8 then again at 2/3 and maybe again at 6/7 then no more.

      1. I’m usually awake from about 3pm-7am. So should I wait until 7/8 pm to initially eat? Thank you!

  14. Hey Jack—quick Q: is a b2b fast from
    Dawn or upon waking? Thank you

  15. Thanks for this article. It makes perfect sense. I do have a question though. I currently do a clean whole food kept I eat TDEE (no deficit) , and 5%C 35%P 60%F. I do an 18:6 (skipping breakfast). I have lost 50 lbs and feel great. I have stalled now for 8 weeks and I am thinking of trying this to break the stall. (I don’t want to give up dairy- maybe I should).. But back to the question. Why is it that I really just don’t want to eat when I wake up. I have no natural motivation to eat.. so extending the fast is super easy. Not eating after 2 is really hard. Why is this. It shouldn’t matter the time of day for the difficulty level for me… it it mental or is there science going on here? Thanks again for your article! its great.

    1. It is a defect of keto (low leptin levels) and weight loss in general as well as a habit from habitually not eating breakfast. Eating should be done with circadian rhythm. This how we are designed and there are many studies coming out now that show simply by eating at dawn and stopping by dusk we can better control weight with no difference in overall calories. Also there has been one study showing that people that ate a bigger breakfast and consecutively smaller meals had better BMIs than those that skipped breakfast or even ate just a small breakfast.

      As you start eating breakfast and stop eating later you will find you are hungry for breakfast as you should be.

  16. Its like you read my mind! You seem to know so much about this, like you wrote the book in it or
    something. I think that you could do with some pics to drive
    the message home a little bit, but other than that, this is fantastic
    blog. A fantastic read. I’ll certainly be back.

  17. Your posts have been *so* helpful for understanding this whole process!! I have two questions:

    1) You mention that “unless we’re working out at night,” because cortisol spikes. But the same would be true of high-stress stuff happening after 2pm, right? Because as an ADHD single parent of two ADHD (one has other issues too) kids and business owner, stress… happens a lot. I’m hoping much of it subsides as my health improves, but… back to IF… would that interfere with it?

    2) I’ve seen some people in my kickboxing group talk about drinking BCAAs before kickboxing. It sounds like it’s helped them, but I wanted to check with you for any possible negative effects for keto or IF?

    Fwiw, I have 90-100 lbs to lose; my BF is over 50%.

    1. 1. Stress is going to interfere with everything wether fasting or not. It is probably worse for those trying to fast. When eating if you have a cortisol spike it will slow digestion and use the food you are eating as fuel for gluconeogenesis. If you are fasting it is going to use lean mass as fuel for GNG.
      2. Most of them have sweeteners in them so I wouldn’t touch them but I have yet to see any actual evidence that they do anything. Only anecdotal and likely placebo effect. I personally have tried every supplement on the market over the years and seen no benefit to any of these things. You get all the amino acids you need from eating protein with meals.

  18. When I go in to have blood drawn for a “fasting blood glucose”, I’m told to not have anything to eat or drink after midnight the night before until my blood is drawn. If I don’t get into the office until 9:00 or later… are you saying that my test results will actually be off due to the dawn affect? Or do you think they take that into account?

    1. Dawn effect is generally from 20 minutes after you wake until 1.5 hours after that. It may skew your fasting blood glucose numbers if you are tested in that window.

  19. This is the right site for anybody who hopes to understand
    this topic. You know a whole lot its almost hard to argue with
    you (not that I really will need to…HaHa).
    You definitely put a brand new spin on a subject that’s been discussed for decades.
    Great stuff, just great!

  20. Hi Jack
    I have adrenal insufficiency so I have suffered for years with my adrenal glands having run out of its stores of cittisol
    After 8 years being ill I was been put on hydrocortisone and I gained weight whilst waiting as I was so knackered I ate and all carbs!! .. Since starting keto in Nov (3rd time lucky after doing prior research) I now take the minimum dose I can which is 10mg at 6 am and 5 at around 2pm as I feel it has helped me stabilise.
    I tend not to be hungry in the morning so have a coffee with cream or a BPC.
    What you say about fasting later in the day does make sense…. I will never EVER do a long term fast. Even 24 hrs as I’d just have to replace more cortisol as it would be too stressful on my body so basically pointless.

    I know you’re not a doctor but I wonder what your thoughts on my doing this would be… I guess until I try I won’t know eh?
    Thanks for reading

    1. My thoughts on not eating breakfast? Well for you it may be different since you are dosing your own cortisol and could technically control your cortisol curve. I can’t really say for sure but typically we are most insulin sensitive in the morning due to the overnight fast but so it is always the best time to eat regardless simply for sheer ease of nutrient absorption. Then again, if you don’t dose cortisol first thing in the am you are not likely having the glucose spike that people with normal cortsiol response have so it may not apply to you.

      That is a tough question to answer.

  21. Jack, if given an option: fast or not to fast for optimal results? (20 lb weight loss and fat loss being the goal for man 240lbs at 5’10” who works out)

    1. My option would be never fast. So far by far the best way I’ve found to get super lean is by overfeeding with mostly fat 80% or higher and returning to maintenance calories. I typically do 4000-5000 cals for 2-3 weeks then return to 2500 and have gone from 215 to 195 in the past year. In the year before that I was fasting at least 3 days out of every week and lost nothing in a year. Started the year of fasting at 214 and ended the year at 215 so I actually gained.

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