Carb Back-Loading, take II

I recently had the pleasure of speaking with John Kiefer and his crew about Carb Back-Loading proper; we discussed the protocol and many other hormonal effects associated with this pattern of nutrient & exercise timing.  Interesting stuff; plenty of fodder for future blog posts…

Brief refresher: skeletal muscle insulin sensitivity is higher in the morning than in the evening.  Exercise boosts insulin sensitivity selectively in muscle, which is relatively more important in the evening.  Thus, an evening carb-load may benefit from exercise to effectively partition the energy influx into skeletal muscle [and away from adipose tissue].

Summary of Part 1 of my CBL review: studies on nutrient timing sans exercise aren’t entirely consistent, in part, due to reciprocal regulation of insulin sensitivity in skeletal muscle and adipose tissue.  That is, excess energy from an evening carb-load, without the exercise-induced, skeletal muscle-specific boost in insulin sensitivity, may be biased less toward muscle growth and more toward fat storage, because unlike skeletal muscle, the sensitivity of adipose tissue to insulin appears to improve as the day progresses… and without exercise to offset this, as in the studies discussed below, this may lead to suboptimal results.

*one thing Kiefer stressed, and I agree, is that the effects of any given intervention may be population-specific.  For example, he pointed out that diurnal insulin sensitivity is less robust in obese and aged populations.  So if two findings aren’t in full agreement, click the link to the study and check this first… context matters!



Tl;dr: I think high intensity exercise and possibly the time of day it’s performed, and regular bouts of fasting, are important factors that mediate the efficacy of CBL and similar protocols.

To get into this follow-up to Carb Back-Loading and the Circadian Regulation of Metabolism, here’s a quote from “Logic does not apply, Part 2: Breakfast,” an article written by John Kiefer (circa 2010… so whether or not this is still his stance, it’s a good platform to delve into the circadian regulation of nutrient partitioning.)

“If what I assume from the facts is true, then skipping breakfast and eating more food at the end of the day rather than the beginning should lead to more fat loss when trying to lose weight, especially if eating breakfast impairs fat burning for the entire day.

So what happened when researchers studied two groups, one that ate most of their calories in the beginning of the day, to simulate the no-eating-after-seven routine, and the other that skipped breakfast and ate most of their meals in the latter half of the day? Damn if I shouldn’t be embarrassed: the group that ate most of their calories early in the day, including a big breakfast, lost more weight than the other group65.

Hold on: there’s more to this story. The researchers also looked at body composition before and after. The morning group lost more weight but lost a lot more muscle and a lot less fat. The night group lost almost exclusively fat and preserved muscle65-69. Who knew, maybe there is something to this science stuff after all?”

Jacobs H, Thompson M, Halberg E, Halberg F, Fraeber C, Levine H, Haus E.  Relative body weight loss on limited free-choice meal consumed as breakfast rather than as dinner.  Chronobiologia 1975;2(suppl 1): 33.

Hirsh E, Halberg F, Goetz FC, Cressey D,  Wendt H, Sothern R, Haus E, Stoney P, Minors D, Rosen G, Hill B, Hilleren M, Garet K.  Body weight change during 1 week on a single daily 2000-calorie meal consumed as breakfast (B) or dinner (D).  Chronobiologia 1975;2(suppl 1): 31-32.

Halberg F.  Some aspects of the chronobiology of nutrition: more work is needed on “when to eat”.  J Nutr. 1989 Mar;119(3):333-43. Review. 

Sensi S, Capani F.  Chronobiological aspects of weight loss in obesity: effects of different meal timing regimens.  Chronobiol Int. 1987;4(2):251-61. 

Study Details

disclaimer: these four studies do not comment directly on nutrient partitioning

Jacobs 1975: 3 weeks, ad lib, all food either for breakfast or dinner

Hirsh 1975: 1 week, 2000 kcals/d, all food either for breakfast or dinner

Both studies showed the same thing: the breakfast-only group lost more weight than the dinner-only group.  In the ad lib study, an easy explanation is that the breakfast group wasn’t as hungry and simply ate less (which actually happened).  However, the isocaloric study showed that when forced to eat the whole 2000 Calories, the breakfast-group lost more weight despite eating just as much as the dinner-group:

Jacobs and Hirsh

The Halberg paper is a rather nice discussion of circadian rhythms and chronobiology, but doesn’t touch on body comp.  And the Sensi paper reported 2 studies, one lasting 3 days and the other 18, with meals given either multiple times per day, only at breakfast, or only at dinner.  No differences in body weight, but higher fat oxidation after dinner (this may have translated to more fat loss had the study gone longer).

Part II

Presumably, one of the better chronic feeding studies to show superior body comp results with big dinners over big breakfast is Keim 1997.  The group given 70% of their calories for dinner group experienced greater fat loss and better preservation of lean mass than those given 70% of their calories for breakfast.  However, this study suffered from some design flaws:  it was an unbalanced crossover with no washout period.

Speculation on how the flaws in study design may have impacted the results: the ratio of fat to lean mass loss is higher at the beginning of a diet… and there were more participants in the PM group for the first 6 weeks.  After 6 weeks of hard dieting, loss of lean mass increases… at this point in the study, the group with more participants was switched to AM (with no washout period).  Ergo, more fat loss with PM feeding; more muscle loss with AM feeding.

In a better executed study, Lombardo and colleagues (2014) gave participants either 70% or 55% of the day’s calories earlier in the day and found the opposite: those assigned to bigger breakfasts lost less muscle and more fat than those assigned to bigger dinners.

In another crossover study that suffered from an inadequate washout period (only 5 days), Nonino-Borges showed no difference in the preservation of muscle, but more fat loss in the group given big breakfasts compared to: 1) big dinners; and 2) 5 small meals throughout the day… the results are in agreement with Lombardo, but that doesn’t make this study design any less bollixed.

The next best support for big dinners is Sofer 2012.  This was a pretty good study; they compared a regular calorie restricted diet with an identical one where carbs were given only at dinner.  And this study DID show more fat loss and less muscle loss in the dinner group.  However, the control group in this study was not “breakfast-only,” but rather “carbs 3x per day.”  Therefore, a more appropriate interpretation of the intervention group is “carbs 1x/d.”  In that sense, it could be concluded that yes, carbs restricted to one meal per day might give better results than multiple carb-meals, but this interpretation doesn’t specify which meal (breakfast or dinner).

There is one other study of relevance: Alves 2014.  The participants were assigned to receive most of their carbs with lunch and protein with dinner, or vice versa, and had a control group with macronutrients evenly spaced out.  THIS is what Sofer should’ve done!  The results showed that carbs with lunch and protein with dinner preserved muscle better than any other group.  Nutrient timing had no impact on fat loss in this study.

Collectively, these studies suggest 1 carb meal is better than multiple carb meals (Sofer and Alves), and earlier carb meals are better than later carb meals (Lombardo and Alves) [in the context of no heavy resistance exercise sessions in the evening].  The studies by Keim and Nonino-Borges cancel each other out 🙂

Summary of Part II

Two bollixed crossovers:
Keim 1997: better results with big dinners.
Nonino-Borges 2007: better results with big breakfasts.

Tie-breaker: Lombard0 2014 -> better results with big breakfasts.

Carb frequency and timing:
Sofer 2012: 1 carb meal is better than 3.
Alves 2014: confirmed Sofer, and showed better results with carbs for lunch and protein for dinner than vice versa.

These aren’t isolated findings: Jakubowicz 2013 and Kahleova 2014 show it as well, but  similar to Jacobs and Hirsh, body composition wasn’t reported, and as such don’t influence the conversation on nutrient partitioning.  I’d also like to stress: 1) these studies are heavily nuanced; and 2) exercise may very well mediate many aspects of this pattern of nutrient timing, and it wasn’t included in these studies.  As mentioned in part 1 and the original text, exercise may be important to bolster PM insulin sensitivity selectively in skeletal muscle, to better manage a PM carb-load…  theoretically, PM exercise would provide greater benefits to a PM carb-load than to an AM carb-load (aka “damage control”),  which I believe may have considerably improved the outcomes in the groups assigned to big dinners or PM carbs.

Part III: Speculation on the mechanism

Sensitivity of adipose tissue to the anabolic effects of insulin increases as the day progresses. 

in contrast to the above, these are acute feeding studies

Zimmet 1974 showed greater suppression of free fatty acids after carbs administered in the evening than in the morning.

Gibson 1975 showed greater suppression of free fatty acids after an insulin injection administered in the evening than in the morning.

Singer 1985 showed, in a 3 meal per day paradigm, that free fatty acids are suppressed more so after dinner than after breakfast or lunch.  Ruge 2009 confirmed this in a similar paradigm… although CBL et al. isn’t exactly a “3 meal per day paradigm,” which introduces variables that may or may not be at play otherwise… indeed, the regular bouts of intermittent fasting most likely contribute to the efficacy of CBL and similar protocols (as does heavy resistance exercise… context matters).

What does suppression of free fatty acids mean?  It reflects increased uptake and decreased release of fatty acids from adipose tissue.  This is a surrogate for fat accumulation and reduced fat oxidation.   The latter was demonstrated by Sacks 1999, who showed that after a morning meal, free fatty acids came back significantly higher than after an evening meal, and this correlated with a faster recovery of ketone bodies (a more specific marker of increased fat oxidation).  Get back into ‘fat-burning mode’ sooner, possibly because of increased sympathetic nervous system activation and energy expenditure while you’re awake during the day… this may not have been the case if an evening exercise session was performed (#context).

FFA and ketones

In agreement with previous studies, insulin secretion was higher after breakfast.  Despite this, fat oxidation increased sooner after the breakfast meal (as evidenced by increased ketones).

Note: the duration of “fasting” can be prolonged by skipping breakfast OR skipping dinner… circadian biology appears to favor the latter.  And the neuroendocrinological response to feeding is highly context-dependent ~ all bets are off if high-intensity resistance exercise is thrown into the mix (especially in the evening, when skeletal muscle insulin sensitivity is reduced).


I don’t think nutrient & exercise timing is going to have a quantitatively huge impact on body composition if diet and sleep quality are crap (unless you like big dinners, in which case PM exercise might be helpful).  Also, adherence is a strong factor… ymmv (context matters).

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  • Most people naturally become hungry late in the day for a reason. The sleep period induces repair/growth of lean tissues and that requires food. Fatigue and lack of desire to be active , even overt sleep is normal after eating a lot of food for a reason as well. Food and attending endocrine response will regulate/inhibit an excessive HPA that would promote muscle loss and fat retention as well as possibly amplifying GH/igf1 & melatonin effects during rest. Insulin may suppress GH but it is required for igf1 (to build muscle) and insulin->serotonin->melatonin->GH in general. OTOH nothing will amp HPA/cortisol like not eating/food deprivation. Poor quality sleep, higher blood sugar, reduced glucose oxidation, reduced fat oxidation greater accumulation in adipocytes etc etc etc.

    Another factor is breakfast foods are horrible nutrition whereas dinner foods are meat and vegetation and root tubers which are much more nutritious. Even though the P/F/C ratios are similar I doubt the foods were. Protein from cereal and milk is not like protein from steak. Carbs from pancakes are not like carbs from potatoes. Butter fat is not like whatever the hell kind of fat is in pop tarts. People crave simple foods at breakfast because people have poor appetites at breakfast. Breakfast is the summer of eating windows (poor appetite, light food) whereas dinner is the fall (higher appetite, circdian intent to sequester nutrition to promote restful sleep and physiological repair).

    Dieters tend to binge at night because the metabolic effects of fasting/hunger are stronger thus harder to resist in evening. The drop in HPA/cortisol promotes hunger and fatigue second to declining IR and FFA (as you stated, reduced IR in adipose and naturally higher hunger from the decline in early day energy mobilization). Oprah’s various pop psychologists will tell you this is caused by “eating your feelings”, but thats because they make stuff up and have absolutely no biological education.

    OTOH, very overfed people can’t eat upon waking, because their superior leptin/insulin inhibits ghrelin and fat storage to total food aversion. Lean/slim healthy people have a better appetite for breakfast than the obese for this reason.

    In general I’ve found eating in the evening and avoiding eating in the day works best. Not only does this tend to promote greater lean mass/superior fat loss but it’s way easier to avoid carbs and such things by eating at night (as carbs are mostly early day food, meat is later day food).

    Side note, I wonder if they controlled for factors like early day use of stimulants? Almost everyone drinks coffee or tea in morning whereas at night they do not, if anything they take SNS inhibiting sedatives. Drinking a cup of coffee with breakfast alone could count for observations like earlier rise of FFA after breakfast relative to dinner.

    • Good point about P/F/C
      …come to think of it this is pretty hard to design for a long-term diet intervention… eg, Keim’s AM group ate more typical breakfast foods overall simply because they were assigned to get 70% of their calories in the morning (I think this is pretty much exactly what you described).

      Sofer reported full meal plans; Lombardo & Alves only P/F/C and vague dietary descriptions

      However, some of the acute studies used pure glucose or insulin in fasted patients, administered in either the AM or PM…

      And in the Sacks study (earlier rise in FFA after breakfast), participants had nothing to eat or drink except water for 5 hours prior to the test. I speculated increased EE and SNS in the AM condition because they said “Patients were confined to a hospital room but not to bed rest.”

  • Thomas Hemming Larsen

    Your last section says it all and is also what I’ve concluded (not that my layman evaluation of CBL means much).
    If diet and sleep quality are indeed good – is nutrient and exercise timing really that important as long as you have your carbs peri-workout so that they are (at least more) selectively used by skeletal muscle.

    • Kiefer mentioned a study by a couple of athlete-scientists which showed no impact of nutrient timing on physical performance. But I BET those guys still drink protein shakes and slam ze carbz in the post-workout “anabolic window”

  • This Old Housewife

    Question: what if you don’t exercise at the same time every day?

    Hubby sometimes works out in the mornings before work, and he sometimes goes swimming after work–the determinant is the weather. The pool he swims at is in a metal building, and the faintest rumble of thunder shuts the pool down for fear of lightning strikes. If there’s rain in the next day’s forecast, he goes to the office gym and works out in the mornings instead of swimming.

    What I’ve done (for better or worse) is to split the calories and the (low) carbs–since his pancreas seemingly requires a 12-hour window to clear excess blood sugar, I pack a “lunch” that he eats for breakfast at work, with a small baggy of pork rinds for mid-day hunger (carbs are in the form of celery sticks or a pickle).

    Dinner is mostly meat, maybe 1 veggie, maybe not. Once weekly, he gets the potato salad treatment. He does not work out after dinner.

    Should I rearrange his meals, the composition of those meals, when he works out, or should this be another Hubby-hacking experiment?

    Whatever it takes to keep him off insulin, I’ll do it. If I could donate part of my own pancreas, I’d do it.

    • I don’t know!
      I guess the only meal timing thing I would consider is to schedule more exercise after the high carb meals, to help acutely manage BG.
      Need more Hubby-Hacking 🙂

      • This Old Housewife

        There ARE no high carb meals, unless you count the potato salad therapy.

  • This Old Housewife

    Have you seen this?

    I stumbled across it at a site talking about Dr. John Rollo’s diet for diabetics (back in 1797–this blows my mind!)–apparently, he’s the ORIGINAL low-carb diet inventor, and Atkins seems to have copied his work. I’m also blown away by the fact that diabetes was discovered as far back as the Egyptians–this makes sense, since their culture revolved around grains.

    ~Here I go looking things up again~

    So tell me again why there’s so much controversy surrounding LC diets and ketosis in general? There’s more science behind it than vegetarianism or veganism for improving health–there was more science behind it than Ancel Keys had time on this planet!

    • I tend to ignore the controversy & politics of nutrition… it’s rarely very interesting 🙂

      I do enjoy reading about the history of nutrition, like John Rollo et al.

      • This Old Housewife

        As for Hubby-hacking, I may have found the Cliff’s Notes version by reading the older stuff (200 or more years old)–seems I’ve been retracing the footsteps of some of these researchers. So more reading for me, and less experimenting from scratch. This stuff is FASCINATING! It may be old hat to you guys, but to see it for myself makes me want to see more if it (diabetes porn?). It also makes me want to order the hard copies and send them directly to my doctor, but I know she won’t be bothered to read them–we have pills for that now, right?

        Anybody know where I can get my hands on opium extract? 🙂

        • opium extract… single-blind hubby hack? JUST KIDDING 🙂

    • *sigh* – it’s been known FOREVER that prior to the discovery/profitibility of insulin that the traditional “cure” to diabetes was an almost all meat mostly fat diet.

      Scroll down to the bottom of this:


      I’ve got a ton of stuff BEFORE science got completely bought out that should be required reading. If researchers actually read the stuff that came long before them there’d be so much less wasted time and dumb arguments.

      In “Lectures on Dietetics” from 1922:

      “As it is possible to live on meat and fat alone without carbohydrates, it was natural to exclude this latter group of food-stuff from the diabetic diet. This was, indeed, done by the earliest observers who had knowledge of the nature of diabetes (Rollo, 1796), and this diet was adhered to with slight modifications until the present time.”
      In “Diet and the Genesis of Diabetes Mellitus” from 1947:

      “When DOBSON had shown in 1770 that the sweet taste of the urine in diabetes, first pointed out by WILLIS 100 years earlier, was due to the presence of sugar, investigations began into the origin of this sugar.

      After it was found that starch was converted to sugar in the intestines, the suspicion arose that diabetes was due to a too rapid digestion of starch to sugar; on this theoretical basis ROLLO (1796) began to treat diabetics with animal diet.

      The guiding principle in the modern pre-insulin methods of treatment was to spare the disturbed carbohydrate metabolism by reducing the carbohydrate content of the food.
      During this period the patients usually received fairly abundant quantities of a diet poor in carbohydrates, and rich in proteins and fat (NAUNYN himself sometimes permitted up to 500 g of meat a day).”


      In “The use of a high fat diet in the treatment of diabetes mellitus” from 1920:

      “The dilemma [ hyperglycaemia or low energy ] can be avoided if the diabetic can safely be given enough calories to maintain metabolic equilibrium, without producing hyperglycemia or acidosis.

      Since carbohydrate cannot be used .. we have dared to ignore the belief concerning the danger of fat in the diet of diabetics, and have investigated in the clinic the effect of a diet whose energy comes largely from fat.”


      Etc etc.

      Does my head in that the people who should know this stuff through the education provided to them are simply unaware of it.


      • This Old Housewife

        In “Lectures on Dietetics” from 1922:
        Reading it now–very interesting.

        Read a few older works too. In one of them, it says that fat should not be restricted, and in one by EP Joslin, it says to omit meat, feed primarily a veg diet, then reintroduce meat carefully. Today, the Joslin Center still follows with the Ornish-type diet, keeping fat low as well as protein.

        The you’ve got the Egyptians doing COMPLETELY the wrong thing by treating with grains, honey, and beer. Sheesh!

        I’m sorry, but for a common housewife to actually see such stuff is mind-boggling…especially in what we’ve totally forgotten over the centuries. Instead of reinventing the wheel each time a drug is developed, wouldn’t looking into these old texts actually SIMPLIFY the research process?

  • Whey Back-Loading™

    9 month exercise study, participants got either whey, soy, or carb supplements: by the end of the study, the soy group was eating more kcals, protein, & carbs than the carb-group, but gained less muscle & more fat.

    Whey protein group gained the most muscle and lost the most fat.

  • alan2102

    I’m trying to square this stuff (items cited below, plus some items cited in the post above) with my current bias in favor of IF with an emphasis on nighttime eating.

    Maybe it comes down to the imponderables of biochemical and psychological individuality and predisposition. Is it easier (for you) to fast all day and eat only at night? Or the opposite? Or does the nibbling pattern work best to control total intake (for YOU) — and is the reduction of total intake sufficient to overcome the fat-storing impact of the insulin spikes? The tea leaves of all the published research can only take us so far; then we have to start experimenting and see what works, for us as individuals.
    J. Nutr. 134:104-111, January 2004
    The Time of Day of Food Intake Influences Overall Intake in Humans
    “The proportion of intake in the morning was negatively correlated with overall intake (r = -0.13, P < 0.01), whereas the proportion ingested late in the evening was positively correlated with overall intake (r = 0.14, P < 0.01)….
    The results suggest that…intake in the morning is particularly satiating and can reduce the total amount ingested for the day, and that intake in the late night lacks satiating value and can result in greater overall daily intake."
    Am J Epidemiol 2003; 158:85-92.
    Association between Eating Patterns and Obesity in a Free-living US Adult Population
    "Results indicate that a greater number of eating episodes each day was associated with a lower risk of obesity (odds ratio for four or more eating episodes vs. three or fewer = 0.55, 95% confidence interval: 0.33, 0.91). In contrast, skipping breakfast was associated with increased prevalence of obesity (odds ratio = 4.5, 95% confidence interval: 1.57, 12.90)"


    • I can’t argue with “personal experimentation.”

      Scientifically speaking, however, please note that most of the studies in this blog are randomized intervention trials. The two you cited are observational / epidemiology. Apples & oranges… I’m not surprised they come to different conclusions.

      • alan2102

        They were consistent with a couple of the studies you cited — Nonino-Borges, and Lombard. Yes, right, observational. But supportive of (consistent with) the other stuff; that’s the point.

        • Hi Alan, good point. Thanks.
          Also, I agree with your take on observational studies – they serve a critical role as part of the scientific method.

  • Kiefer recently wrote about the Alves study:

    I hate stats as much as anyone, but the CarbNite group (NCDP) lost a significant amount of fat-free mass. This didn’t happen in those who abstained from carbs at night (DCNP). And fat mass declined by a [statistically] similar amount in both groups.

  • Also, don’t discount the undoubtedly important role of prolonged fasting daily. Very small eating window.

  • Breakfast Downgraded From ‘Most Important Meal of the Day’ to ‘Meal’

  • Here’s what went down in the Alves study (carbs with lunch or dinner): fat mass significantly declined in ALL 3 GROUPS. Muscle mass significantly declined in the control and Carb Back-Loading group, but not in those who abstained from carbs at night.

    Alves study:

    Adel aka Prof. Dr. Andro thought the control group won:

    Kiefer thought the CBL group won:

    As far as body composition is concerned, I think the low carb high protein dinner group won.

  • 4precious

    Hello Bill,
    Found your site after reading about you on Kiefer’s blog. Good stuff – thanks for reporting.

    But now I’m pretty confused. Kiefer is a big “work out later in the day” guy but you’re saying muscle sensitivity to insulin DECREASES throughout the day while fats sensitivity “INCREASES”. So it sounds like working out and eating earlier is the way to go. I have no idea how he came up with the opposite so I guess this is maybe a question for him.

    From a practical standpoint I always think about meal timing as “solving the 4 hour problem”. (i.e. trying not to eat) If you eat dinner at 6 or 7 you then have a long time before bed while fighting the urge to snack. Or skip breakfast and be a bit hungry but know the calories are coming. I prefer skipping breakfast and eating a late dinner but your data on insulin points to the opposite being more optimal if I understand it correctly. (And in the end you say all of this is probably not a big swinger)


    PS Do you know Dr. Peter Attia? He’s down in your neck of the woods and seems like it would be good if you guys were talking.

    • Kiefer and I agree on way more things than we disagree (eg, podcast:

      That said, in the original CBL model, I don’t think the circadian regulation of adipose tissue insulin sensitivity was taken into account. He had other reasons for setting it up around a PM carb-load (in both of our views, adherence is likely much more important than timing).

      My take is that exercising & skewing more total food intake earlier in the day is more “optimal,” whereas doing it in the evening is more “damage control” (… but neither will work if it doesn’t work with your lifestyle (imo, skipping breakfast and exercising after work is far more convenient for most people).

      As to your “4 hour problem,” when I say “skewing more total food intake earlier in the day,” this could almost be applied solely to insulinogenic foods (ie, carbs)… so a fattier dinner might solve your “4 hour problem” without causing an insulin spike at a time when adipose insulin sensitivity is at its peak.

      But I honestly think nutrient & exercise timing is a small piece of a very large puzzle. If one way works better for you, go for it, otherwise, don’t kill yourself trying to make it work.

  • Pingback: Interesting: meal timing vs circadian rhythm | Mark's Daily Apple Health and Fitness Forum page()

  • Dr. Lagakos,

    My name is Joe Flaherty and I’m a self proclaimed nutrition nut (almost to a point of fault). I’m absolutely enamored with your work, so keep it up! I had the pleasure of listening to the Body.IO podcast that you were featured on and will go back and relisten for further clarity… but I’m all about self experimentation, and I think one is in order based off of your findings.

    About a year and a half ago, I dove into CBL headfirst and saw some GREAT results. It actually dovetailed off of the end of a run of using IF with an 8 hr feeding window between 11 am and 7 pm.

    Over the course of 71 days, I went from 176 lbs down to 166 lbs, my waistline went from 33.25″ to 31.75″ and my strength went through the roof. All of these changes happened quickly and held for those 10 weeks; I could finally, finally, FINALLY see my abs in the mirror! Before trying that diet, I had tried almost everything in the book to try and get to that level, but nothing had ever worked as well or as rapidly as CBL.

    Now, this may sound like a ringing endorsement for CBL, and for 10 weeks, it really was. Trust me, I was spreading the word like gospel about how to shift carb intake. But a waterfall of life stressors (i.e. working three jobs, reinjuring my back, moving, etc.) opened the door for me to view my backloads as a way to relieve that mounting stress. I am a fat kid at heart, after all.

    Since then, I’ve really been lost in my diet endeavors. I’ve bounced around between CBL, CNS (which also working eerily well the first time around, allowing me to lose 30 lbs in 50 days, but didn’t work so well when I tried it successive times) and full on ketogenic dieting with marginal results.

    One of my biggest blocks is paralysis by analysis; sometimes I believe ignorance is bliss, ergo the awesome success I had with CBL and CNS the first time around and the piss poor results I had as a follow up. Overanalyzing and tinkering with every new finding was my downfall!

    But I truly believe your findings in your Afternoon Diabetes post is a change worth implementing. Since reading CBL, the idea that insulin sensitivity for BOTH tissues decreases during the day had basically become fact in my world; your findings show that while muscular sensitivity follows that pattern, adipose sensitivity is reversed. This is mind blowing for me. Essentially, in the morning, the body already creates the state that CBL is trying to construct (high muscular insulin sensitivity/low adipose insulin sensitivity)… without having to do a single thing.

    Add in the GLUT 4 translocation brought about by heavy resistance training, and I can clearly see why you posit that shifting the CBL guidelines to the AM would be way more optimal than the “damage control” route of a nighttime carb feeding.

    As you say, context is everything, and maybe PM exercise is that big game changer. But it can’t be THAT drastically different from AM exercise to think that this AM CBL wouldn’t be worth a shot.

    On top of that, “CBL Proper” didn’t fit my lifestyle all that great. I’m a morning person and love to workout fasted for some reason. I was just so scared by the CBL logic to not workout and then carb load in the morning, figuring I’d be doing myself a big disservice.

    Your findings give me reason to believe that shifting CBL to the morning is exactly the thing I need to get back to that level I used to be at. After all, both you and Kiefer agree that adherence is the biggest factor, and this would help me adhere better.

    Tl;dr version – I’m going to be trying out CBLagakos (I’m going to have to trademark that)

    AM: Fasted training, clean carb load (white potatoes) with insulin spiking goodies (whey isolate, leucine), followed by a little cold thermogenesis

    Rest of the day: Ketogenic diet

    I’d reason that restricting carb intake to 1x/day in any regard would have benefits, and shifting this load to the morning would have benefits across the board. Hell, blasting music and blue light from the gym may serve me much better in the AM, and staying away from carbs later in the day may even allow me to sleep better at night.

    I wanted to let you know that I’d be trying this version of CBL out on myself in hopes of returning to my CBL glory days. I have a fitness/nutrition blog of my own that I may restart, and if/when I do, I’d be happy to shoot you a link with my progress on this diet protocol.

    I am so grateful for people like you that dig for a more optimal way to partition calories and manage body composition. I love to geek out on this stuff as well, but your understanding of the topic is far greater than mine. So THANK YOU (x1000) for bringing these findings to light, and keep on digging! I’ll be right by your side digging in the same ditch, albeit with a smaller shovel 😉

    My best,

    Joe Flaherty

    • EPIC!!! 🙂

      “in the morning, the body already creates the state that CBL is trying to construct (high muscular insulin sensitivity/low adipose insulin sensitivity)… without having to do a single thing.”

      “without having to do a single thing.”

      EXACTLY. CBL proper is excellent damage control… But AM calories & exercise might be optimal… but like you mentioned, it has to work for your lifestyle.

      • Which I’m very eager to find out!

        As far as body comp goes, I’d have to believe that the differing insulin sensitivities in the morning have to be the biggest consideration. But the more I mull it over, I do remember a few other reasons Kiefer advocates sliding the carb load backwards in the day. It mostly has to do with cortisol and GH release in the morning aiding with fat burning. Since they both peak in the AM, it would seem to make sense to allow them to “do their thing” so to speak in a low BG state. But on a grand scale, just HOW BIG of an impact is that cortisol and GH spike having on lypolysis? And by having no carbs later in the day and allowing a lesser level of those hormones to impact fat burning, are they THAT MUCH less effective? I can’t image it being orders of magnitude less efficient…

        Far from me to slight Kiefer, as I’ve been avidly following his work for years now. But your position on timing the carb load, and also your references to back up your claim, really have me questioning his logic.

        Again, that’s why I’m so excited to tackle this experiment!

        • “It mostly has to do with cortisol and GH release in the morning aiding with fat burning.”

          These aren’t *great* reasons, imo (ie, you can spin ’em either way). GH actually peaks shortly after you fall asleep, and it’s lipolytic effects are going to be blunted if you’re swimming in insulin. And what better way to offset the potentially proteolytic effects of an AM cortisol peak than with a bolus of protein 🙂

          • A good reason to do it later in the day (CBL proper), imo, is that skipping breakfast is much easier for most people, and I think “intermittent fasting” is definitely a big reason why people have success with this program… regardless of when the fasting window is.

          • Really appreciate all of the responses Bill, some great things to help ease my conscious as I go against the CBL dogma that has been ingrained in my head for so long.

            “you can spin ’em either way”

            I wish data wasn’t that easy to spin! No disrespect to Kiefer, but next time I get my hands on a diet book with references, I have to do a little more due diligence vetting out the info before diving in. I’m so glad there are people like you who actually take the time to challenge some of the notions intelligently in search of a more optimal way.

            As far as GH goes, I’m definitely with you on the idea of nighttime release being > daytime release in terms of body comp effects. I’m under the impression that physiological doses of GH won’t do much in terms of muscle gain/fat loss, and that hormonal release at night would at least go towards facilitating recovery.

            As for cortisol, I never really considered the flip side of that peak in the morning. I was always under the impression that letting it roam free without insulin would be very catabolic for fat tissue, which it probably is… but I never considered how blunting that peak would be beneficial, especially following an AM workout.

            I will admit, skipping breakfast is easy to do, and I still do it to some extent with a fasted workout in the AM. Speaking of fasted workouts, I was wondering if you have any information on that protocol being effective for muscle growth? I know you are a big proponent of pre workout protein (which is another subtle change I may tinker with in the future), but Kiefer uses this citation ( ) to basically state that a fasted training session followed by a protein/carb/leucine shake “doubles the anabolic response of a regular, pre-fed training session.”

            I’m going to brush back over that study, but do you see any merit to this?

          • fasted vs. fed vs. alternating.
            I think, in some contexts, no big difference between fasted & fed exercise, in the long-term.

            In that Deldicque paper, a lot of MPS markers were mixed, some higher for the breakfast group (particularly those sampled prior to exercise), others higher for the fasted group (post-workout)… the data are really all over the place!

            That said, this study doesn’t shift my views that fed/fasted doesn’t really matter. Both have advantages!

          • This is awesome! So glad you can interpret this stuff because I sure couldn’t!

            Definitely see the differing benefits/reasons for training fed or fasted. For my scenario, would the postworkout protein/carb/leucine mix cover me? Do you think a whey isolate shake on the way to the gym would optimize things? Or is the postworkout bolus enough for growth purposes?

            Sorry to be so specific!

          • I honestly don’t think it’ll make *that* much of a difference. Pre, peri, or post. If #1 goal is anabolism, do all 3! 🙂

            I’d just make sure the “pre” was immediately prior – like you said: “on the way to the gym”

          • Haha that method might make me very anabolic but my wallet very catabolic! Something to consider though.

            I went on a research tear again in hopes of solidifying your theory that adipose tissue gets more sensitive as the day goes on, and I found this gem of a study…


            BUT… after perusing through, I couldn’t really get a definitive answer to what I was looking for. Some of the graphs indicated adipose tissue followed the same pattern as muscle, while some data seemed to show the exact opposite trend (i.e. the one you propose).

            Would you mind making a molehill out of this mountain for me? 😉

          • Wait a second, I think I found something!

            From “Downregulation of Fatty Acid Trafficking in Obese Individuals” ( )

            “In order to estimate the relative quantity of the meal fat that was stored in adipose tissue, the fat content of each meal was divided by the calculated whole-body net fat storage during the three consecutive 5-h meal periods. In lean males, there was progressive increase in the deposition of meal fat into adipose tissue with each meal (13, 35, and 47%, first to third meal, respectively, P < 0.001)"

            IN LEAN MALES! Context matters! Please tell me I just proved your point!

          • awesome find!

          • *Some* rhythms in adipose might follow skeletal muscle, but the one I’ve been going on about, insulin sensitivity, doesn’t…. figure 8 confirms this; did I miss something that shows otherwise?

          • That’s what I was thinking but I couldn’t be too sure. I’m actually aggregating this info and am going to send it along to Kiefer himself to see what he thinks. I hope he gets back to me!

          • That’s an interesting study, and it goes to show you that even “fasted vs. fed” isn’t an accurate dichotomy. They essentially carb-loaded 90 minutes prior to exercise… now THAT’S what I call “fed” exercise.

            In my protein pre-workout Rx, you’re basically taking a protein-rich meal on your way to the gym, so the amino acids are peaking while your muscles are contracting. Not exactly “fed,” as above, but not technically fasting either.

          • Lastly, as to the Deldicque study, the data are all over the place! Some MPS markers were better for breakfast group, others better for fasted group.

            And at different times… it looks like (for some markers) the breakfast group was more anabolic after breakfast, prior to exercise, whereas the fasting group was more anabolic after the post-workout protein shake… makes me wonder about net 24 hour totals…

            In my opinion, this study alone doesn’t make a compelling case for fasted exercise.

            Tl;dr: I don’t think fasted vs fed is a game changer! 🙂

        • “I can’t image it being orders of magnitude less efficient…”

          agree 100%. Small piece of a big puzzle.

          That said, I’m a fan of Kiefer’s work. For one, it’s novel. Also, I think the original concept of CBL, including high intensity resistance exercise to offset PM muscle IR, in the context of damage control is great!

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  • Summary, of sorts:

    1. Eat more calories in AM (eg, ~60-70% AM / 30-40% PM)

    2. Exercise around meal time.

    3. If exercising in PM, then still probably better to skew more calories in AM, but less so than if exercising in AM (eg, ~50-60% AM / 40-50% PM)

    4. If eating carbs in PM, then should probably exercise in PM to offset damage. From a nutrient partitioning perspective, this is theoretically the least optimal.

    In other words, what is your evening priority? if it’s exercise, then similar rules apply. BUT IF it’s carbs, then should exercise in PM.

  • Thomas Hemming Larsen

    I just heard a Q&A with Jacob Wilson who said that you’re temporarily insulin resistant after weight training. Wouldn’t that destroy the idea of having high carb meals right after weight training as they would do even more harm?

    • that statement is a bit confused.

      Heavy training-induced muscle damage will cause IR the following days, like DOMS… and part of the enhanced exercise-induced glucose uptake into muscle is not mediated by insulin: muscle contraction stimulates GLUT4 translocation.

      • Thomas Hemming Larsen

        Thanks for clarifying Bill.

  • John Hanson

    My personal basal testing says the opposite: we are most sensitive to insulin in the afternoons and least sensitive in the mornings.

    Most diabetics are aware of the Dawn Phenomenon (DP). This is the effect of early morning hormone releases which decrease our insulin sensitivity. Every pumper knows they need to increase their dawn basal rates and lowering of afternoon rates. Many often feel sleep in the afternoons. I always attributed it as an effect of low blood sugar which my BG testing bore out.


      I too experience Dawn Phenomenon and PubMed is filled with references to DP.

      When I say that I experience DP I have years of data showing that, for the same meal, I need more insulin in the morning than I do in the afternoon, to control my blood sugar.
      For this reason I decided a few months ago to eat one meal per day in the afternoon. My total insulin needs have dropped markedly though I eat the same number of calories and macronutrients.
      For all my life, I was a big proponent of breakfast and never skipped it. Careful examination of my blood glucose data convinced me to change my ways.

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