For reasons I’m still struggling to understand, the idea of “nutritional ketosis” (NK, to be distinguished from starvation ketosis, SK or diabetic ketoacidosis, DKA) is often discussed and debated in much the same way as religion or politics. Perhaps this can be said of all nutrition, which is a shame. Nevertheless, in my continued defiance of such sensitive topics, I’d like to add another layer of complexity and nuance to this discussion.
The “rule of thumb” for NK is that caloric intake is determined as follows (this excludes a subset of ketogenic diets known as calorie-restricted KD which, as the name suggests, is specifically restricted in calories):
- Carbohydrate (total, not “net”): less than 50 gm/day, but ideally closer to 30 gm/day
- Protein: up to 1 to 1.5 gm/kg, but ideally below about 120 gm/day
- Fat: to satiety
Let me illustrate what this looks like for Joe (left), Jane (middle), and Jeff (right — an example of a calorie restricted KD), three hypothetical people in NK — but each with different caloric requirements.
As a general rule, as caloric requirement increases the proportion of calories derived from carbohydrate and protein decreases (and the contribution of dietary fat increases), even while absolute intake of carbohydrate and protein increases.
Anyone who has bought a blood ketone meter knows how tough it can be to get “into” ketosis by carbohydrate restriction (since everyone asks, I use the Abbott Precision Xtra meter which uses two different strips: one for glucose and one for beta-hydroxybutyrate, or BHB). Most practitioners consider the minimum threshold of NK to be a fasting serum level of BHB above 0.5 mM. I’m a bit more stringent in my practice and like to see fasting BHB levels above 1 mM. To give you a sense of one person’s numbers (mine), over a 6-month stretch in 2013, when I was in NK, my mean (i.e., arithmetic average) morning fasting level was 1.7 mM with a median value of 1.4 mM. The highest morning level during that period was 5.2 mM. (The highest morning level I have ever measured in myself is 5.7 mM.)
But, it took me a long time to get it right, especially since at the outset of my foray into NK I was consuming between 4,000 and 4,400 kcal per day. (My average daily caloric intake for weight stability was about 3,800 kcal per day, which was validated by doubly-labeled water.) I could still easily “fall out” of NK. For example, on my daughter’s 5th birthday she insisted I have some of her tikka masala (contains lots of sugar), naan bread, and mango ice cream. How could I say no to a birthday girl who insisted on going to the nicest Indian restaurant in San Diego? As to be expected, the next day my BHB was 0.2 mM, and it took me 2 days to get back above 1 mM.
Here’s a little secret I’m about to let everyone in on… I like carbohydrates. I love sushi (though I now mostly eat sashimi). I love Indian and Thai food, though I prefer to make curry myself to keep sugar out. I make (and eat) the best hummus this side of the Nile River. I’ve figured out how and when I can eat them to meet the following conditions:
- Stay in NK (except on a few occasions like my daughter’s birthday);
- Increase my anaerobic performance;
- Preserve most (but not all*) of the benefits I enjoyed when I was much more strict about my ketogenic diet.
How, you ask? By learning to calculate my glycogen deficit.
(*) For me, the leanest body composition I achieved as an adult was in strict NK with no attempts to do what I’m about to describe below. Since I’m not a model and nobody cares if my body fat is 7% or 10%, I’m happy to be a little less lean if it gives me the flexibility to increase performance and live a slightly more sane life. At least for now.
PLEASE NOTE: I have never suggested, and can’t imagine I ever will suggest, that a KD is “best” or “right” for everyone. What I describe below may seem extreme, both in the amount of work required and the actual application. I fully acknowledge that (1) this is a highly analytical approach to eating, and (2) that I’m a “freak” (my wife’s words, not mine). I certainly don’t do this often, unless a lot is on the line (e.g., a big ride), but I like having this technique in my armamentarium.
If you’ve watched my presentation from 2013 at the IHMC, then you’re familiar with RQ. Through years of metabolic testing I have a pretty good sense of my RQ at any moment in time – when I’m sleeping, when I’m sitting around (most of the time), when I’m riding my bike at 200 watts, when I’m riding my bike at 400 watts, when I’m lifting weights, etc. This allows me to calculate what proportion of my energy I derive from glycogen and what proportion I derive from fatty acid. Consider the following example:
If I ride my bike at an average of 185 watts (you’ll need a power meter to infer this) for, say, 2 hours, I know my average RQ is between 0.76 and 0.80.
The approximate formula is %CHO = 3.333*RQ – 2.333, which can easily be derived from the observation that %CHO utilized increases linearly from 0% at RQ 0.7 to 100% at RQ 1.0.
Furthermore, I know my VO2 at 185 watts is 2.9 liters per min, which means (using the Weir formula which I presented previously) my energy requirement was about 14 kcal per minute, or 1,680 kcal over 2 hours. Hence, of these 1,680 kcal needed to pedal 185 watts for 120 minutes, 336 to 554 kcal came from glycogen. In other words, I utilized between 84 and 138 gm of glycogen.
(By comparison, several years prior to being in NK, this effort in me would have taken place at a slightly higher VO2 – closer to 3.2 liters per min – and at a much higher RQ – between 0.90 and 0.95 – meaning the exact same work output would have required somewhere between 300 and 400 gm of glycogen! That’s a real state of metabolic inflexibility. Basically, I was entirely dependent on carbohydrates for energy.)
Since the first metabolic priority for ingested carbohydrate is glycogen replenishment, I can, in this setting, consume probably somewhere between 60 and 120 gm of carbohydrate following this ride and stay in ketosis. Why? Because those carbohydrates are prioritized to replenish my glycogen stores AND I am highly insulin sensitive. Note the *AND* in this last sentence. (The especially astute reader will realize some of this glycogen debt will be replenished by protein and glycerol, the latter of which is liberated by lipolysis – see post on fat flux for a primer).
Clearly I didn’t consume this amount of carbohydrate on my daughter’s birthday, so why was I out of ketosis the next day? Because my glycogen debt was not high. Of course, I knew this and didn’t really care. But, if I know my wife wants to go out for sushi one night, and I know she’s going to make me eat a California roll, I can “rig it” such that I show up to dinner with a glycogen debt appropriate enough to enjoy them without significantly interfering with my liver’s BHB production.
Extreme example
At one point, I did two tough bike rides on consecutive days. Each day we rode 110 miles under challenging conditions. Over 6,000 feet of climbing each day and very strong winds, which were either headwinds or cross-winds. On top of this, we rode pretty fast. For the purpose of illustration I recorded everything I did and ate on the second day, which I rode a bit easier than the first day.
The second ride took 6 hours and 5 minutes. My average normalized power output was 225 watts, and arithmetic average power output was 184 watts. Based on mechanical work output, this required about 5,000 kcal. Factoring in the other 18 hours of that day, my total energy expenditure was about 6,800 kcal for the day, obviously not an average day. (A detailed explanation of where the extra 1,800 kcal were expended is beyond what I want to get into now, but it’s basically the energy required to keep me alive – transport ions, contract voluntary and involuntary muscles, etc. — plus move me around, and digest food).
So what did I eat that day?
- Breakfast (pre-ride): 5 scrambled eggs, 2 sausage links, 3 pieces of bacon, coffee with cream.
- In ride nutrition (I spread this out over 6 hours): 14 oz (not a typo) of salted cashews, 2 Quest bars, 1 peach, 1 apple, 6 bottles of Biosteel High Performance Sports Drink, water. (Since I know someone will ask, I did not consume super starch this day since I was craving cashews as my carbohydrate source and was craving more sodium, given the 90+ degree temperature.)
- Late lunch/early dinner (post-ride): 2 oz ham, 3 oz pulled pork, large salad with oil and vinegar dressing, 2 slices of cheddar cheese, 6 mini hamburger patties, 2 tomatoes.
What did this amount to?
- Fat – 351 gm, or 3,160 kcal of fat
- Protein – 245 gm, or 980 kcal of protein
- Carbohydrate – 321 gm, or 1,284 kcal of carbohydrate
(I used package information and Nutritionist Pro software to calculate this.)
Hence, on this day I consumed about 5,400 kcal in total at the following ratio:
- Fat – 58%
- Protein – 18%
- Carbohydrate – 24%
By all conventional wisdom I should not have been in ketosis the next morning, right?
The following morning, my BHB level was 2.2 mM and blood glucose was 5.1 mM.
Teaching point I can’t resist: Following 2 days of significant caloric deficit, about 3,000 kcal in total, I should have in theory lost about a pound (mostly fat, possibly some muscle) which would have been noticed on a scale. Instead, I gained 8 pounds over those 2 days! Sure it was mostly water retention, both from the glycogen (small) and the fluid accumulating in the interstitial space (“thirds space” fluid losses, large) due to a systemic inflammatory response. This happens under extreme conditions of exercise. In fact, the harder I exercise, the more weight I gain, transiently. I am at my absolute lightest following 2 days of travel (i.e., rest). So before freaking out at the sight of the scale, keep in mind that most day-to-day weight movement in our bodies is indeed water movement into and out of the plasma and interstitial space, respectively.
What’s my point?
Context matters! If I ate even one-quarter of that amount of carbohydrate and two-thirds of that protein on a normal day – say, 2.5 hours of riding or 1.5 hour of riding followed by 1 hour of swimming, or a day of travel with no exercise – I would have been out of ketosis for two days or more. (Of course, my appetite on those days would not have allowed me to eat 5,400 kcal without feeling sick, but I won’t get into that until a later post.) But on this day, with these glycogen demands, I was able to maintain the perks of ketosis AND glycolysis simultaneously.
There are days, though, when I overshot my glycogen need and end up with a low BHB and high fasting glucose the following morning. Conversely, there are days I underestimate my glycogen depletion and wake up with very high BHB levels and very low glucose levels (i.e., BHB levels higher than glucose levels, when both measured in mM).
Final thoughts
I felt a bit like I was in unchartered territory because the literature on nutritional ketosis hadn’t really (to my reading) explored this level of extreme activity. In future posts, I may write about other experiences and self-experiments, including my experience with exogenous (i.e., synthetic) ketones (which I did not use on this ride, but have experimented with on other rides – no, this is not “raspberry ketones” or other such gimmicks).
2017: You can read about one of my earliest experiences with exogenous ketones in this post.
Are carbohydrates necessary to produce 225 watts or more for hours on end? Yes. But, the key is knowing how much you need and when to take them. A lower RQ at a given level of intensity means less demand on glycogen. In my experience, working with athletes and non-athletes, most tend to make two errors (for lack of a better word):
- They over-estimate their carbohydrate requirement, and/or
- They forget that no factor influences RQ – and therefore substrate requirement – more than dietary composition during lead up to event (or “life”, which is sort of the ultimate event).
Know your engine, first. Then fuel it appropriately.
You state’the first metabolic priority for ingested carbohydrate is glycogen replenishment’. Does this also apply to glucose generated by hepatic gluconegenisis?
If the glucose being made by GNG is not immediately being used, then yes, glycogen formation should still be top priority (i.e., same as ingested).
Peter,
Maybe you or a reader can help. I’m 63, with no metabolic syndrome markers and under 10% BF. I think being near or in ketosis is a healthy way to live and after a gradual effort lasting around 3 mo. I finally went into ketosis a few days ago. The next day I went on a somewhat hard 45 mile (5500′ climbing, NP of 215w.) ride. I’m going to give Superstarch a try, but my order hasn’t arrived. On this 3 hour ride I nibbled over the course of the middle 90 minutes a fruit/nut bar with 20 gms of carbs and sipped some sports drink with 18 gms of carbs. I felt great at the end but just couldn’t eat enough the rest of the day without overdoing the carbs (I was already at 100 gms) and wound up 900 kcal short of what I should have eaten. The next day I went on what should have been an easy 55 mi./3 hour spin (1500′, NP 190). I did it with an all protein breakfast and just water. I was pretty tired at 2 hours and the final 10 minutes were a real struggle. I ride 150+ miles a week and these two back to back rides were nothing unusual. I realize my carb fueling was off. Here’s my question: Is there is anything in the way I fueled (of didn’t) for this second ride that would have caused extreme muscle soreness in my thighs? I suffer from DOMS no matter what I do, but usually not for 48 hours. This soreness was not noticeable while riding, but started the minute I got off the bike, has not gone away in 24 hours and is extreme, even for me. Are there any reports of excessive muscle soreness during early ketosis that you are aware of? I hope you have time to comment. Thanks for all you do.
“Not sure of your conclusion, but great to see the process.”
LOL! Not only does your blog provide a wealth of useful information but also a wealth of entertainment.
Please don’t ever stop this blog. I absolutely LOVE it. You are a saint 🙂
Monica
I was wondering if you check your blood ketone levels and the time frames to do this.
would I do this in the morning, after intermittent fasting, after eating, before eating, when do I do this?
what are the best times to do this?
thanks
I enjoyed reading your article Ketones and Carbohydrate can they co-exist. Regarding maintaining ketosis. I have a keto ratio calculator on my site at https://www.flexibleketogenic.com/ . If the ratio (based on the Woodyatt formula) is above 2 you can be sure you’re in ketosis. If you over eat carbs you can still maintain the ratio by increasing fat until you reach the desired ratio. This may mean depending on how many carbs you ate that you have a day with a large number of calories, but you won’t lose keto adaptation. The ratio is all important in maintaing ketosis. Try is I’ll be curious what you find.
I just recently discover your blog, and I would like to thank you for all hard work and great posts. I’ve been on NK for two weeks and I’m training everyday at lunch time at work. Before NK I was able to do sprints on around 85%MHR, but while on NK I’m not able to sustain 85% of MHR for long. My question is for ANAREOBIC training when I should eat carbs ? Do you have some basic rules how to use carbs with ANAREOBIC training and when to eat them, before or after training ?
Thanks
Hi Peter,
I read in your post that one day you had Indian dinner on your daughter’s B’day and It took you 2 days to go back into ketosis (>1 mmol). I got a bit surprised that you could get back in such short period. I mean, it took me around two weeks to reach > 1 mmol level when I started my own experiment with Ketosis. How were you able to do that?
Is it because your body was already in the keto adapted state and so it still had preference to burn more fat than carbs ? Also, During fully keto-adapted state, if someone does carb loading, does your body just shifts to burning glycogen totally and you go back to square one ?
Probably because I had already been in ketosis for so long.
I have watched some for your youtube videos and read several articles on your site. I have had past success on a very low carb, high protein diet ({Protein Power by Drs. Eades). But I was afraid to eat fat and thus had to consume tons of protein to eat enough. It worked for years, but then I started adding carbs back, had several kids, and gained a ton of weight. I am just learning about Paleo diets, and so have been doing Protein Power (loosely) and with Paleo foods. Eating 1200 calories a day, 20% fat, 10% carbs, and 70% protein. I’ve lost @ 4 lbs a week. Now that I am reading that Ketosis cannot happen without much lower carbs and much higher fats, I am adding coconut oil, avocado, almond butter, etc. But I am still confused about 2 things, I am hoping you can help with. SOME say protein can be as high as 120-150 g a day, carbs 30 grams, and the rest fat. But if I understand your examples here, I should be eating much less protein and more fat. I am a 40 yo female restricting calories to 1200 net daily, after adding back calories burned 3 days a week weight training. I am really afraid to eat too little protein and too much fat. (1) What are the recommended actual macro %s for someone on a calorie restricted diet to allow for getting into and staying into Ketosis, as there seems to be a wide range of opinions on this? (2) If I raise caloric intake, how much do those macros change? I need to lose 60 lbs. (3) Does it matter if the %s are kept in balance for each and every meal, or is it ok to eat mostly protein in the morning, with lunch having just salad and an avocado (low protein) for example? (4) What is the max amt. of protein I can eat (or %) and stay in Ketosis? Thank you in advance for answering my questions and for your great website!
I have since found a min. protein calculator, keto calculator, and ketostix. So I now understand some of my questions. I still would like to know 2 things if you get a chance to respond (I know your are very busy). (1) Do I need to maintain the keto ratios at each meal, or is each day sufficient? I would presume each meal for optimal insulin regulation. (2) My ketostix stay Mauve, about 4 Mmol, so I believe I am in ketosis. When I use a keto-calculator (on flexibleketogenic website) it gives me a range of 1-1.5 mild ketosis, 1.5-1.9 moderate ketosis, and 2.0+ optimal ketosis. I have been in the mid-range consistently. It there a need to be in the 2+ range or to get to eggplant purple on the ketostix (8 Mmol) in order to be in ideal nutritional ketosis, or is moderate level still fine I am losing weight? I cannot find this info. anywhere and want all the benefits of ketosis. What is your recommendation for target range?
Hi Peter,
I was wondering if what they call “low carb limbo” was a fact or myth. Is it true that you must either be producing ketones for the brain or consuming at least 150g a day of glucose, otherwise your brain won’t have sufficient energy and you will essentially hit a wall?
Thanks,
Sam
Hi,
Fantastic site and great posts!
I have just been “experimenting” with ketosis for about 3 weeks, mainly due to a big jump in blood sugar levels (stable 4.2 in 2011 to steady 5.7 -5.9 in 2012-4) . My exercise levels are not what they were (about 1-1.5hr (post kids) ) vs 3-4hrs pre 2008 ( pre kids, when racing) but these are still well within healthy activity levels. I weigh 62kg more or less and hold about 49kg in lean mass (DEXA)- another “fat” but fit! . At my leanest (virtually starving myself), i weighted in at 53kg but actually my fat mass was relatively high for an athlete at around 15%. My target is about 56-57kg , around 15-17% body fat with blood sugars back to pre kids levels! (3.8- 4mmol)
I have been “experimenting ” for a bout 3 weeks on net carbs 0.5mmol) and secondly, the slightest deviation sends me right back to home base. and it takes days to get back even to 0.4mol. I also notice the type of exercise certainly impacts post exercise ketone levels- very similar to one of your previous blogs)
The other thing becoming apparent is that even with low total carbs < 30gram , as soon as my protein intake exceeds about 60g , ketosis stops! I wonder if some people are also more sensitive to dietary protein requirements than others and how this influences the availability of fat for fuel.
I recently listened to a talk on how,, when left alone, various species choose their dietary protein preferences- Chimps were around 14% of total energy intake, dogs were about 14%, cats were about 50% and humans were about 12%. The important thing was the % of protein remained surprisingly constant across the period of the study (about 1 month from memory), (although different life stages had different % protein preferences) suggesting that it was the % protein in the diet , not the protein content (grams) that was important to the animal.
However, It's actually quite hard to stay around this level (12% protein) on a normal western diet, particularly when in calorie deficit i wonder that in certain subgroups of people with fat mobilization disregulation , this protein set point also plays an important part in the obesity puzzle- ie their protein "tolerance" is on the low end and the excess protein consumed is essentially being converted to glucose and resulting in elevated insulin levels which ultimately inhibit that individuals ability to utilize stored fat- maybe this is why resistance training can sometimes be useful in reducing fat mass , particularly when on a low carb diet, it simply increases the protein requirement and shifts your set point so that your protein utilization is greater -hence reducing the amount of protein available to be broken down into sugars.
I also wonder whether the same phenomena of insulin resistance and obesity that we see in humans is prevalent in companion animals- diabetes is one of the fastest growing pet ailment- possibly fuelled by v high carbohydrate and high protein , relative to their % requirements, despite energy content of the food often being in line with requirements,
Again, just observations and my two cents worth and no research backing! I might try to play around with protein % rather than grams to see if this helps me on my quest.
Keep up the great work!
Thanks for a great set of articles.
A couple of questions:
1. Can ketosis and glucolysis co-exist or they are mutually exclusive? I. e. if ketosis has started, does that mean that energy consumption through carbohydrates has stopped, or these two processes can go in parallel?
2. Does ketosis start only when glycogen stores in the liver are fully depleted? If the priority for the digested carbohydrates is to first top up the glycogen stores and then to be used for direct energy supply, does that mean that in ketosis there is ALWAYS some amount of carbohydrates that can be eaten without taking the person out of ketosis?
1. Yes
2. No
Hello Peter, I watched an excerpt from Dr. Michael Greger M.D.,, who went on to state that the cause of diabetes is saturated fat… He’s promoting a whole plant based diet. Are you familiar with his ’cause’ as he states? And if so, I would love to hear any comments you have on his statements of what he calls ‘science’.
thanking you now, Van
Hello. I’ve been planning on doing my strength powerlifting program and HIT training in the near future.
I believe this follows your NK regime, but my plan is ketones meals with the exception of five TBSP of TwinLabs MCT Fuel (roughly 30g glucose and 22.5g MCT Oil) pre workout . Then followed by 50+ or – g of carbs from sweet potatoes. Then keto meals afterwards all at caloric surplus.
Is that something you recommend and is that similar to your NK example?
I just hope my body fat doesn’t increase so much. I may have to lower the carb intake to prevent that after I conduct this trial.
Thanks.
Do you have any blog or article on starting the keto adaptation….I am struggling with side effects. Thank you
Hi Peter and all readers,
Quick question: Do you know the ATP yield of of BHB per mol of respired 02?
I have read that it is higher than the 120 kcal/mol 02 of glucose, but I cannot find the actual number anywhere……
Thanks a lot if you have the time.
I am an avid crossfitter and believer in ketosis. Last year, at the age of 45, I made the team to go to the northern california regionals with five other twenty something year olds. I weighed 138 pounds and had 17 % body fat at that time. I was encouraged to eat more carbs to be able to manage the increased workload in preparation for the big competition. I did. Over the course of about 8 months, I gained 6% body fat, 20 pounds and only 2 pounds of muscle mass. My diet was primarily Paleo with some starchy veggies, otherwise pretty “clean”. I have been trying to get back into ketosis now for about a month. My carbs are as low as 10-20g a day, and my macro’s are 80% fat, 15% protein, 5% carbs, give or take. Testing my unine, blood and breath and I am generally in small to moderate ketones with these numbers. Highest I’ve been is 2.2mmol blood. I have lost no weight. Actually, I have gained about 2 pounds, depending on what time of the day I weigh myself. My abdomen actually feels bloated most of the time. This is an unusual response for me as I usually drop unnessecary weight easily while in keto. I’m taking all the appropriate and relevant micro-nutrients. Would love any feedback. I train high intensity work outs about 5 times a week for about 2 hours. I have been eating aobut 1600 cals in an attempt to create a calorie deficit. Quite confused.
Hi Barbara,
I just read your post and wanted to share with you my experience as it seems pretty similar. The abdominal bloating that you describe would be something to look into. I had initial success of losing body fat and gaining lean tissue while in nutritional ketosis until I started experiencing abdominal bloating. Like you I started cutting calories but my weight kept fluctuating and I actually gained body fat. I discovered that I was highly intolerant to the whey protein that I was ingesting post workout through food sensitivity testing. I was also sensitive to a few other foods which was eating on a regular basis like sweet potato. After cutting them out I also made sure I had the proper nutrients for digestion and gut barrier repair. You might be interested in this study: https://journals.cambridge.org/download.php?file=%2FBJN%2FBJN108_05%2FS0007114512001213a.pdf&code=7c558bb9cbb56662a22b52fd9ff5084a
It gives an insight on high fat intake, inflammation, metabolism and gut health.
“Would love any feedback. I train high intensity work outs about 5 times a week for about 2 hours. I have been eating aobut 1600 cals in an attempt to create a calorie deficit. Quite confused.” <– This may be the issue. You could try increasing your overall calories to match your output. Forget about dieting for a month and see if eating more makes a difference. You can then reduce your food slower to create a deficit.