Many pre-diabetic, diabetic, and insulin resistant people have used the low carbohydrate diet to successfully manage their blood glucose levels.  It just plain works.  FACT (P<0.05).

However, a small subset of this population fails to achieve normal fasting glucose.  This is likely due, in part, to a type of circadian mismatch induced by aberrant meal timing and excess exposure to artificial light at night.  For an extensive list of citations supporting the former, see “Afternoon Diabetes;” stay tuned for evidence of the latter.  In brief, a combination of delaying food intake for as long as possible after waking in the morning (“skipping breakfast”) and consuming most calories at night = no bueno.  These behaviors can also promote a circadian mismatch and phase delay.  Hint: eat when the sun is up; sleep when it is down.




Two more pieces of evidence:

Exhibit A. Influence of night-time protein and carbohydrate intake on appetite and cardiometabolic risk in sedentary overweight and obese women (2014)


In this study, the participants were asked to have a late-night snack about an hour before bedtime, consisting of ~30g whey protein, casein, or carbohydrate.


After doing this for just a few days, they all required significantly more insulin to maintain normal fasting glucose:


glucose insulin HOMA-IR


Avoiding carbs at night (both protein groups) seems to do slightly better regarding energy expenditure, but this doesn’t negate the impact on insulin resistance imo:


whey casein carbs



Elevated insulin levels are seen in the pre-diabetic state and generally precede impaired fasting glucose… pseudo-Dawn Phenomenon?




Exhibit B. Impact of bedtime snack composition on prevention of nocturnal hypoglycemia in adults with type 1 diabetes undergoing intensive insulin management using lispro insulin before meals (2003)


Admittedly, the context of this study is very different, and not at all looking at the impact of skipping breakfast + late night eating on fasting blood glucose… but it sort-of-did, albeit indirectly.


The bedtime snacks:


bedtime snacks


Focus on the grey areas:


hyperglycemic episodes


Grey area = impaired fasting glucose.  Regardless of baseline fasting blood glucose (<7 mM, 7-10 mM, or >10 mM), and meal composition, eating late at night resulted in fasting hyperglycemia… consistent in two wildly different patient populations (obese/overweight women in the first study; type 1 diabetics in this study).  Ergo, this more likely reflects a bona fide circadian phenomenon.  Best advice?  Dawn is a good time to phe-NOMNOMNOM, or break your fast.  Cut down on food intake at night and I bet you’ll be hungry for it.  “Cut down” =/= skipping dinner; just keep it light and preferably prior to sunset.



Part 2. Does coffee count as breakfast?


Imo, a fast is broken with calories… but this is my opinion, and whether it’s BCAAsprimal coffee (with egg yolk), bulletproof coffee (with butter or MCTs), or regular coffee (with cream) hasn’t been fleshed out experimentally.  Until that is done, I don’t see anything wrong with bacon and eggs.  Or a hearty kale & mushroom omelette (hahaha “kale,” which I think tastes pretty nasty IRL).  Or whatever, just don’t avoiding eating for as long as possible after waking only to binge at night: the available evidence does not support this strategy (see above, and here).

Ymmv?  Perhaps, but it’s not scientific (or logical): if skipping BF & having late dinners is how our ancestors actually ate, it may have been the most efficient way to accumulate fat mass, in order to survive periods of famine.  (But that’s all speculation.)

At night, have a light dinner, avoid artificial light, and sleep well.  That’s all I got.

Oh yeah one more thing: some LC advocates think LC makes circadian rhythms irrelevant, or perhaps none of this applies in the context of a low insulin, ketoadapted state.  That is wrong given that many still have elevated fasting blood glucose levels… and it’s a silly notion: circadian rhythms always apply, because we’re humans, who evolved on Earth.


calories proper



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  • Gerard Pinzone

    Eat only during the day and never at night? I picked a bad time to convert to Islam.

  • Michelle

    Interesting, I have switched my IF to be early in the day, ending no later than about 3 ish, first meal early and quite large and my FBG has been 73! Not the 95 ish before. I eat a ketogenic diet, have for almost two years, since switching timing, better numbers. Other things probably play into it too, but this was pretty dramatic.

    I usually eat a large meal, about 2/3 my macros at 10 am and then finish up with the last of my protein and some veg by 3 pm. I like to have 4-5 hours between meals too.

    I really can’t eat earlier, or I would, as I workout from about 8-9:45 am. Now, if there is a family function, something special going on, i am not ‘bound’ to this eating pattern, it is just my norm. And, if i happen to be somewhere for ‘dinner’ that has only junk to eat, i can choose to just fast until the next day, because i already ate 2/3 of my macros anyway, i won’t die

    I have not eaten at night for years, i think this eating and ending earlier may have been the missing link for me. A disclaimer, i did do a 14 day fast in March that I believe dramatically slashed my insulin and got thing going in the right direction. BUT, I still had somewhat higher FBG, until changing to eating early and not later. I was eating, before switching timing, between 2 pm and 5 pm. Just switched everying earlier

    • Martin

      Michelle, I thought about adopting the pattern your write about, starting early and esp. finishing early by 3pm. My problem though is: It is very easy for me not to eat in the morning till early afternoon, I feel great mentally and energy-wise. But if I do not eat in the afternoon/evening I don’t do so great, I get hungry, irritated, almost anxious. Did you have to go through an adaptation period?

      • Michelle

        Martin, it is super easy for me not to eat in the morning and being on keto for along time now, I have great energy and mental acuity, BUT, I trusted a good friend, Raymund, and the science he presented and took the leap. It is also hard, as I still have 8 children still at home and do love that we eat dinner together. I know just purpose to sit with them, enjoy conversation and serve them. Much easier to serve when one is not stuffing their face. 😉

        the only real adaptation period was getting myself to eat enough early in the day. I had the same struggle when I first started eating optimal protein, had to almost force it, but once I got there, I know wake up very hungry and can eat very well right after my workout. It was only a few days, though, nothing insurmountable. I highly recommend. I have been noticing a great energy early evening and it is so nice to go to bed empty. Hope that helps. Try it, I bet you will like it.

    • NY

      Hi Michelle,

      What about the length of fasting time between your last meal and breakfast next day? Is it the same at FBG of 73 and FBG of 95?

      • Michelle

        NY, not entirely sure what you are asking, but I no longer have FBG of 95. Even if I eat a later meal for family reasons. It is always about 18-19 hours between my last (small) meal and my break-fast. Pretty much low 70s every day.

    • Thanks for sharing, Michelle!

  • Martin

    I belong to this small subset of population. Long time ago I made this observation that my fasting blood glucose gets lower when I eat breakfast. I am on a very low-carb diet, btw.

    The thing is: I never feel like eating in the morning, I feel full regardless how much I eat the previous night. I can skip breakfast and do well mentally till noon or so and only then have my break-fast. I can do long runs or any other sport without eating. I just feel great skipping breakfast except my fasting blood glucose is not so good, e.g. around 100 this morning, much too much.. So what do I do? MCT/coconut oil with my coffee?

    • dunno, maybe start small, like 1 egg & a piece of bacon?

      “Feeling great” is definitely important, but impaired fasting glucose = no bueno.

      • Andre S. Almeida

        How much should I eat for breakfast

        I am currently eating only protein and fat (eggs, chicken breast and vegetables) for breakfast.

        At lunch I’m eating meat, eggs, vegetables, 1/2 avocado, 1 tablespoon of olive oil and some carbohydrates (100-120g beans).

        Sometimes I eat dinner, sometimes not. What do you recommend?

        I do weight training once a week (as indicated by the book ‘body by science’) and HIIT once a week (running) and I eat a banana after finishing training.

        I also do Carbnite once a week.

    • Nathan

      I have the same problem, whether I am eating low-carb or not. Skipping breakfast is easy, but my fasting glucose definitely goes up when the bulk of my calories are at dinner.

  • NY

    Hi Bill,

    I wonder if in the studies showing late eating as bad and early eating as good, the following 2 variables are controlled/ accounted for:

    1. Number of calories at dinner.
    2. Time gap between dinner and breakfast next day.

    A light dinner will have a less impact on BG after say 12 hours as compared to a big dinner.

    If I eat dinner at 10 PM my fasting BG next day at 10am would be 85. If I had the same dinner at 8PM, my fasting BG next day at 10am would be 78 but this is after 14 hours of fast whereas BG of 85 is after 12 hours of fast. Would also achieve FBG of 78 at 12PM next day with 10PM dinner the night before (14 hours fast).

    • interesting q. For the most part, only morning test time is controlled; late eating is specified as a certain amount of time prior to bedtime (eg, 30min), and bedtime is different for everyone.

      As a rule of thumb, I go by: dinner prior to sunset, breakfast at sunrise, and sleep in between.

  • Larry Rotenberg

    I suffer from t2d and dawn phen is the main symptom even ketogenic so I am switching eating patterns/artifical light and will let you know in a month or so

    • Cool. Look forward to hearing if this helps.

      • This Old Housewife

        I can tell you that zero carb has DEFINITELY worked for Hubby. Dawn Phen is a thing of the past!

    • Larry Rotenberg

      this has crushed dawn phenomena…!!!! blood sugar 5.4 this am….last night 4.7 …. no meds what so ever….pre levels were 7 to 8 in am and 5 to 6 in evening

      • Larry Rotenberg
      • awesome!

        • Larry Rotenberg

          New morning low 4.3.

      • daz

        Congrats Larry,
        So to summarize…
        What changes did you make…?

        • Larry Rotenberg

          Basically on ketogenic diet but dawn phen started about 6 months ago (prior t2d under control)….about 6 weeks ago did a 19 day water fast……then changed eating pattern such that within 30 minutes eat a large meal…3 eggs and 7 oz salmon.plus coconut oil olive oil……usually 6 am…..then around noon ate 7 oz chicken salad and steamed cauliflower broc zuci….plus some pecans and spicy feta …kept the meals same to reduce variables….also 2 hr total walking to/from lunch rest……no supplements vitamins etc….this morning blood glucose 5 or 90……..lowest yet…was between 7 and 9…..i never took metformin etc….next step blood work end of nonth….meters are often wrong by 15 %…..my approach is similar to jack kruse leptin rx….goto his website

  • Tony

    Is there a morning feeding window that’s ideal? Or do I need to keep a turkey leg on the nightstand?

    • this hasn’t been rigorously tested, although I see no reason to delay; as early as is convenient for you?

  • Hahaha 🙂

    Sumo Wrestlers’ Tricks for Getting Big

    1. Don’t eat breakfast. Sumo wrestlers never eat breakfast. This is a great way to slow your metabolism way down and will definitely ensure over eating later in the day.

    2. Exercise on an empty stomach. When you exercise without proper fueling, your metabolism will conserve every
    ounce of energy you have left to get you through the activity. So you end up burning far less calories than you would have had you eaten prior to exercising.

    3. Eat only 1-2 meals each day. Sumo wrestlers get up early, work out and then don’t eat until late in the day. This way they will be starving and will eat anything they can grab
    and in enormous amounts. This ensures a great calorie surplus and maximum weight gain. When you eat a large amount of calories in one sitting, the body will use up what it can and then fill your extra energy reserves for later. When your storage gets full, everything left over is stored directly as fat.


    • “Skipping breakfast and working out instead slows down the wrestler’s metabolism, so sumo wrestlers usually don’t eat until around 11am.”

    • NY

      AWESOME! All three apply to me whenever I attempt IF. Reminds me of Gary Taubes’ chapter on energy conservation in GCBC.

    • Nathan

      I don’t think this is entirely correct.

      1. I skipped breakfast for more than a year and gained no weight. (Wasn’t really trying to gain or lose at the time.) I was almost never hungry, frequently fasted 16-20 hours, and functioned reasonably well. My fasting blood glucose was in the 90’s, which isn’t so great.

      2. I also exercise on an empty stomach, and my metabolism hasn’t slowed down at all. In fact, my daily caloric intake has gone up 25% over the past 3 months and I’ve only gained a tiny bit of weight. (Much less than I’d like.) Fasted cardio is quite popular among weightlifters, bodybuilders, and physique competitors, all of whom are interested in maintaining a high metabolism. I do eat pretty much immediately after resistance training, not for metabolic reasons but for muscle repair.

      3. Now that you’ve convinced me to eat breakfast, I sometimes eat 2500-3500 calories for my post-workout meal. So far, I haven’t gotten fatter. My fasting glucose is back into the 80’s, so I think I’ll keep up with the breakfasts, but I’m still struggling to put on pounds.

      • “My fasting glucose is back into the 80’s, so I think I’ll keep up with the breakfasts, but I’m still struggling to put on pounds.”

        glucose numbers look good; can’t really comment on the ‘struggle to gain weight’ w/o knowing more context….

        • Nathan

          My goal is to put on between 20 and 30 lbs of lean mass. Assuming that 25-50% of total weight gain is likely to be adipose, it’s going to take me a very long time to get there.

          I put in 3-4 hours of barbell-centered resistance training each week. As much volume as I can squeeze into 2-3 workouts, and the weight is progressively increasing. I’m gaining perhaps 1lb/month, but my daily caloric intake has gone from ~2400 (rough guess) to ~3200 (as precise as I can manage) over the past year. I’ve put on roughly 10 pounds. My waist size has been stable to within 1/2″ or so. I’ve experimented with fed and fasted training and I prefer fasted training because I don’t have digestive discomfort (see below). I almost always train early in the morning.

          My satiety levels are through the roof: I frequently feel stuffed from before I’ve finished breakfast until I’m ready for bed. Keeping my caloric intake artificially high like this ranges from uncomfortable to very painful. I prepare most of the foods I eat: eggs, meat, fish, nuts, fruit, vegetables, oats, honey, rice, and potatoes are my main foods. I get 0.8-1.2g protein/lb of body weight. My feeding windows are longer on workout days for all the reasons mentioned so far. I frequently go several weeks without consuming alcohol, so I don’t see it as a major source of calories.

          I started tracking my sleep, and I’m averaging close to 7.5 hours/day, which seems reasonable. There have definitely been periods of sleep deprivation during this time, but I’ve also allowed myself time to try to work off my sleep debts.

          I’ve been managing SIBO-type symptoms for a while now, mostly by intermittent fasting and the occasional dose of raw garlic when my stomach bloats up. Wheat causes mild-to-severe skin problems for me (typically dose-dependent), perhaps due to some intestinal permeability. It would be nice to have the time/money to fully diagnose my digestive problems, but I can at least cope with the mess.

          When I stopped my SAD diet in 2011 I dropped close to 4″ off my stomach, mostly fat. I can definitely put on belly fat, but not so easily with my current food choices. I’ve never been athletic or muscular, so I’m stronger now in my mid-30’s than I was in my teens or 20’s.

          Is that enough context to help?

          • Thomas Hemming Larsen

            Just curious. What are your macros like?

          • Nathan

            I do both high- and low-carb days, so macros vary. My main focus has been keeping my protein intake in a decent range (averaging 120g/day). Carbs range from 400-550g on workout days and 60-200g on non-workout days. Fat can range from 130-250g on workout days to 70-170g on non-workout days. Normally either fat or carbs will dominate at 45-60% of calories on a single day. I try to push into the 55-60% range as often as possible, but I don’t hit it as consistently as I’d like.

      • Dan Ordoins

        Leangains approach. Works for me, skip breakfast, workout fasted, largest meal post workout. If taking in carbs done more so in the post workout meal ( I do a keto diet), and an 8 hour eating window (I do 8-4 hours) which allows for an earlier lighter dinner of good whole foods. Leangains counts calories. I find good in the beginning as an education but not needed when things are in order and context is good.
        I bet context matters. For someone lean or lower in body fat and healthy works wonderful. Someone insulin resistant, over weight and circadian rythm out of whack it go be “no Bueno”.

        • Nathan

          I haven’t read Leangains, I just do what I do mostly of necessity. I started tracking calories due to frustration with slow progress, and also because I’ll have a lot of nice data to analyze when I’m done.

    • Nathan

      I blame the liquid calories and excess semi-empty carbs (beer and rice). I’d probably fatten up on that, just like I did on cereal and milk.

    • Thomas Hemming Larsen

      For a second I thought that it was you saying that. Then I realised the link… 😀

    • TechnoTriticale

      Malcolm Kendrick just posted on carbs & conventional wisdom, and Sumo came up. Turns out they don’t get diabetic – as long as they keep up the training.

      • 2 heavy exercise sessions per day seems to neutralize *some* of the negative impacts of their robust obesity; leaves them with very high muscle mass and relatively high SCAT:VAT ratio.

        Eg, http://bit.ly/1Jrkc1r: “The incidence of diabetes mellitus may increase in retired wrestlers who do not continue physical exercise, if they continue heavy caloric intake*”

        *haven’t seen any long-term follow-up studies (eg, after retirement), but I suspect: no bueno (regardless of continual “heavy caloric intake”)

    • Miodrag Mili?

      Isn’t exercising on a full stomach considered bad ?

    • Dan Gregory

      OMG I just realized I’m on the Sumo protocol: LCHF edition. Shockingly, I’m having trouble getting lean…

  • This Old Housewife

    The above also applies to a zero-carb diet.

  • Colin P. Müller

    I eat one meal a day…a huge dinner around 6 in the evening. I’ve done so every night for the last three years and I’ve dropped from 304 to 157 in the process. No exercise, either. I get great sleep, also. The only supp I take is Carlson’s liquid fish oil with my dinner. (I know..I know…it’s supposedly better to eat fish instead but I’m not a fish fan unless it’s fried)

    • that’s some really great progress. Congrats!

  • Thomas Hemming Larsen

    Would exercise in the afternoon work as ‘damage control’ wrt. to a bigger dinner?

    • Nathan

      In general, exercise of sufficient intensity improves muscle insulin sensitivity, so this sounds likely. I’m not an expert though.

      • Thomas Hemming Larsen

        That’s also my thinking. I’m just not sure how big the circadian element is.

  • Pedro Luis Schütz

    Carbnite am adept done post-exercise (once a week) .This is OK?

  • Amzad Chow

    Hows it going Bill. I have a few questions for you. so I was wondering at what time would insulin sensitivity be the greatest? I know the fast throughout the night during sleep would be enough to induce insulin sensitivity but also that the high cortisol release in the morning may also make us less insulin sensitive. So when would be the ideal time to consume the greatest amount of carbs independent of any physical activity?
    Also what are your opinions on insulin mimetics like Berberine and Alpha Lipoic Acid

    • “So when would be the ideal time to consume the greatest amount of carbs independent of any physical activity?”

      I generally don’t advocate consuming “a great amount of carbs” (at any time of day), but to answer your question, morning. This is when insulin sensitivity is high in skeletal muscle and low in adipose tissue (most favorable nutrient partitioning).

      Berberine & alpha lipoic acid might be helpful in some contexts, but probably not as effective as exercise, for example.

  • Eve

    I had to revisit this post because my results from an annual physical showed my fasted glucose level to be 100, which is prediabetic. I don’t have anything to compare it to, but that number surprised me, because I work out and generally eat lower carb. My BMI is in the normal range, although I’m heavier than I want to be and can’t shed weight. I do eat late at night and tend to have my first meal (not counting coffee with milk) in the late morning or early afternoon. I wonder whether this is a contributing factor.

    • might be worth a go… start with a small dinner, a few hours earlier than usual. Then maybe you’ll be hungry, earlier in the morning than usual.