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The Science of Ketogenic Exercise

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{{Skeleton}}Introduction/Summary.There is remarkably little scientific research available around exercise while on a ketogenic diet[[Ketogenic Diet]]. The only useful research I found was a single study by Phinney in 1983. This section While this is a brief review fascinating study, it has few subjects, it has not been confirmed with other studies and the results of the available study are somewhat ambiguous. I've included some other studiesthat are on [[Non-Ketogenic Low Carbohydrate Diets]]. __NOTOC__* =Phinney-'s Study of Elite Cyclists=A classic study was performed in 1983. This study looked at by Stephen Phinney on the effect of four weeks on a [[Ketogenic Diet]] on 5 elite cyclists, and found that on average their endurance was maintained<ref name="Phinney-1983"/>. However, this average represents two subjects that dramatically improved their endurance, one that didn't change and two subjects that had dramatically reduced endurance. One of the subjects that had reduced performance was [[Overtraining| Overtrained]], and if their results are excluded the average is a 13% improvement. ** The diet was 15% of calories from protein, 85% from fat, with less than 20g of carbohydrate.** Subjects were performed [[VO2max |V̇O₂max]] and endurance tests before and after the [[Ketogenic Diet]]. * The five subjects had an endurance time of 147 minutes on the normal diet and 151 minutes on the [[Ketogenic Diet]]. However, the individual responses are rather different. ** Two subjects dramatically increased their endurance time on the [[Ketogenic Diet]], one by 57% and another by 30%. ** One subject had an almost identical endurance time. ** Two subjects had a dramatic decrease in their endurance, one by 36% and another by 28%. The subject that decreased their performance by 36% had complained of overtraining and had reduced his training level the month before the trial. * Of the five subjects (see table below for details):** JP: Endurance improved by 57% and had much lower final muscle [[Glycogen]] levels on the [[Ketogenic Diet]] than the normal diet (41.5 compared with 59.2). ** IK: Endurance improved by 30% and had similar final Glycogen levels on normal and Ketogenic Diets. ** MK: Endurance was the similar (2% improvement) and had higher final Glycogen levels on the Ketogenic Diets. ** BK: Endurance reduced by 28% and had higher final glycogen levels after the ketogenic endurance test than the normal diet (38.1 compared with 58.4).** WB: Endurance reduced by 36%.*** WB was Overtrained and reduced training volume from 300 miles/week to 100 miles/week.*** WB had higher final glycogen levels after the ketogenic endurance test than the normal diet.*** WB had higher VO₂ on the Ketogenic Diet. * Unlike typical fat metabolism, the oxygen cost of calories was not different on the [[Ketogenic Diet]]. *** There are some similar observations from other non-exercise studiesThis is a huge deal, as the big problem with burning fat is that it requires more Oxygen to produce the same amount of energy. However Phinney provides no details of the power outputs. ** The RQ on the VO2max test dropped from 1.04 to 0.9, and on the endurance test from 0.83 to 0.72, indicating a shift in substrate metabolism. However, because Ketone metabolism can produce RQ values that vary significantly, it's not possible to estimate what fuel is being metabolized<ref name="Schutz-1980"/>. (The conversion of fat to Ketones consumes Oxygen without producing Carbon dioxide, the metabolism of Ketones has an RQ of 1.0, with the overall RQ matching that of Fat<ref name="Schutz-1980"/>.)** The endurance test did not include any fuel, just water. It is likely that the endurance test would have had a better result in the control condition with carbohydrate supplementation. ** Blood glucose during the endurance test was similar after the [[Ketogenic Diet]] to before, but the rise and fall were somewhat reduced. At no point did blood glucose drop to the point of hypoglycemia. Blood glucose provided an estimated 28% of calories on the normal diet and 9% of calories on the [[Ketogenic Diet]]. ** Blood levels of the [[Ketones| Ketone]] 3-hydroxybutyrate(BOHB), which indicates ketogenisis, were insignificant on the normal diet and elevated (1.28 mmol/L) on the [[Ketogenic Diet]].** Muscle glycogen [[Glycogen]] levels where higher before the endurance test on the normal diet than on the [[Ketogenic Diet]] (143 and 53 respectively). Both tests had similar muscle glycogen levels after the endurance tests. It is interesting to see that muscle glycogen levels were replenished somewhat on the [[Ketogenic Diet]], even though the subjects continued normal training for the four weeks. ** The five subjects had an endurance time {| class="wikitable"! ! Endurace-1! Endurance-2! Change! Glycogen Pre-1! Glycogen Post-1! Drop in Glycogen! Glycogen Pre-2! Glycogen Post-2! Drop in Glycogen! Change in final levels! Difference in drop! VO2-1! VO2-2! Change|-| JP| 148| 223| style="background-color: #63BE7B;" |51%| 144.8| 59.2| style="background-color: #AED480;" |-59%| 81.7| 41.5| style="background-color: #F8696B;" |-49%| style="background-color: #F8696B;" |-30%| style="background-color: #63BE7B;" |-10%| 3.30| 3.20| style="background-color: #FDC77D;" |-3%|-| IK| 100| 130| style="background-color: #A5D17F;" |30%| 179.7| 62.9| style="background-color: #FFEB84;" |-65%| 67.5| 63.5| style="background-color: #63BE7B;" |-6%| style="background-color: #FEDF81;" |1%| style="background-color: #F8696B;" |-59%| 3.10| 2.97| style="background-color: #F8696B;" |-4%|-| MK| 178| 181| style="background-color: #FFEB84;" |2%| 142.8| 46.6| style="background-color: #FA9272;" |-67%| 65.1| 57.6| style="background-color: #8CCA7E;" |-12%| style="background-color: #C1DA81;" |24%| style="background-color: #F97F6F;" |-56%| 3.09| 3.01| style="background-color: #FFEB84;" |-3%|-| BK| 169| 121| style="background-color: #F98470;" |-28%| 120.8| 38.1| style="background-color: #F8696B;" |-68%| 80.7| 58.4| style="background-color: #FEE883;" |-28%| style="background-color: #63BE7B;" |53%| style="background-color: #FFEB84;" |-41%| 3.79| 3.97| style="background-color: #B6D680;" |5%|-| WB| 140| 89| style="background-color: #F8696B;" |-36%| 124.9| 57.8| style="background-color: #63BE7B;" |-54%| 82.6| 60.1| style="background-color: #FFEB84;" |-27%| style="background-color: #FFEB84;" |4%| style="background-color: #B7D780;" |-26%| 2.61| 2.95| style="background-color: #63BE7B;" |13%|-| Average| | | 4%| | | -63%| 75.5| | -24%| 10%| -38%| | | 2%|-| Exclude WB| | | 13%| | | -65%| 73.8| | -24%| 12%| -41%| | | -1%|}=Other studies=There are a few other studies that are of 147 minutes on interest, though they do not directly deal with exercise capacity and the Ketogenic Diet. ==Non-Ketogenic Low Carbohydrate Diet (NKLCD) and Exercise==A 1994 study looked at the normal effect of a low carbohydrate diet on cycling performance<ref name="Lambert-1994"/>. This study explicitly avoiding being ketogenic, providing calories from 67% fat, 7% carbohydrate and 151 minutes on the 25% protein, with a control condition of 70% carbohydrate. The exercise test protocol was rather unusual; a maximum strength test was followed by a [[High Intensity Interval Training| Wingate test]], then a high intensity (85% [[VO2max|V̇O₂max]]) endurance test to exhaustion, a 20 minute rest, then a moderate intensity (50% [[Ketogenic DietVO2max|V̇O₂max]]) endurance test to exhaustion. The high fat and high carbohydrate conditions were not statistically different except for the moderate intensity test where the low carbohydrate condition produced significantly better endurance (80 minutes rather than 43.) However, while the high intensity exhaustion test was not significantly different, the low carbohydrate condition was only 8.3 minutes rather than 12.5. This is not statistically significant, but it does suggest the high carbohydrate condition could have been far more tiring than the low carbohydrate condition. There have also been other studies showing that a rest period between exercise bouts can produce low blood glucose<ref name="Russell-2014"/>, so this study might be the result of the individual responses are rather differentunusual structure. *** Two ==Exercise capacity in obese subjects undergoing Protein Sparing Modified Fast==An earlier study by Phinney looked at untrained, obese subjects that were treated using a Protein Sparing Modified Fast (PSMF) that provided 500-750 Calories/Day<ref name="Phinney-1980"/>. Because a PSMF requires medical supervision, the subjects dramatically were in admitted to a medical facility for the 8 week study. Using a treadmill walking test to exhaustion showed that endurance dropped to 80% of baseline after one week, but after [[Ketoadaptation]] their capacity increased to 155%. This is a fascinating study, but the nature of the subjects, their endurance time on weight loss, and the difference between the [[PSMF and a Ketogenic Diet]], one by 57% all make it hard to draw general conclusions. ==Post-exercise ketosis in post-prandial exercise- effect of glucose and alanine==A study of 33 trained endurance runners on a low carbohydrate diet looked at the effect of glucose and another by 30%alanine (an amino acid)<ref name="Koeslag-1985"/>. The subject whose endurance improved by 57% had much lower final muscle glycogen levels diet was not ketogenic as their blood BOHB was only 0.23 and they were on the diet for only 48 hours before the tests (no [[Ketogenic DietKetoadaptation]] than the normal diet ). This study showed that 50g (41.5 compared with 59200 Calories) of Glucose before or immediately after a 90 minute half-marathon distance run did not impact blood ketone levels.(Taking 50g 2hours after exercise will cause a dramatic drop in ketone levels). *** One subject had an almost identical endurance timeHowever, the alanine reduced ketone levels when taken before or after the run. *** Two subjects had ==The effects of a dramatic decrease ketogenic diet on exercise metabolism and physical performance in their enduranceoff-road cyclists==This study looks promising, but sadly it does not appear to actually use the Ketogenic Diet<ref name="ZajacPoprzecki2014"/>. The diet the study used consisted of 70% fat, one by 3615% protein and another by 2815%carbohydrates, and provided an average of 2,865 Calories, which works out to ~145g of carbohydrate per day, a level generally considered far too high to be Ketogenic. In addition, while the [[Ketone Levels]] increased, the level of BOHB only rose to 0.15 mmol/L. The subject that decreased their performance by 36% had complained recommended minimum level to be considered Ketogenic is 0.2 mmol/L (BOHB+AcAc)<ref name="Robinson-1980"/>, though other researchers recommend a BOHB level of overtraining and 0.5<ref name="Phinney-2011-p31"/>. While the study was not Ketogenic, it had reduced his training level the month before subjects on the triallow carbohydrate diet for four weeks to allow adaptation. **** The subject that low carbohydrate diet reduced their body fat, which explained some improved performance by 28% has metrics. The low carbohydrate diet also resulted in a higher final glycogen levels after the ketogenic endurance test than the normal diet (38.1 compared with 58.4)oxygen requirement.

{{KetoSeeAlso}}

=References=

<references>

<ref name="ZajacPoprzecki2014">Adam Zajac, Stanisław Poprzecki, Adam Maszczyk, Miłosz Czuba, Małgorzata Michalczyk, Grzegorz Zydek, The Effects of a Ketogenic Diet on Exercise Metabolism and Physical Performance in Off-Road Cyclists, Nutrients, volume 6, issue 7, 2014, pages 2493–2508, ISSN [http://www.worldcat.org/issn/2072-6643 2072-6643], doi [http://dx.doi.org/10.3390/nu6072493 10.3390/nu6072493]</ref>

<ref name="Koeslag-1985">JH. Koeslag, LI. Levinrad, JD. Lochner, AA. Sive, Post-exercise ketosis in post-prandial exercise: effect of glucose and alanine ingestion in humans., J Physiol, volume 358, pages 395-403, Jan 1985, PMID [http://www.ncbi.nlm.nih.gov/pubmed/3884775 3884775]</ref>

<ref name="Robinson-1980"> AM. Robinson, DH. Williamson, Physiological roles of ketone bodies as substrates and signals in mammalian tissues., Physiol Rev, volume 60, issue 1, pages 143-87, Jan 1980, PMID [http://www.ncbi.nlm.nih.gov/pubmed/6986618 6986618]</ref>

<ref name="Phinney-1983">SD. Phinney, BR. Bistrian, WJ. Evans, E. Gervino, GL. Blackburn, The human metabolic response to chronic ketosis without caloric restriction: preservation of submaximal exercise capability with reduced carbohydrate oxidation., Metabolism, volume 32, issue 8, pages 769-76, Aug 1983, PMID [http://www.ncbi.nlm.nih.gov/pubmed/6865776 6865776]</ref>

<ref name="Russell-2014">M. Russell, D. Benton, M. Kingsley, Carbohydrate ingestion before and during soccer match play and blood glucose and lactate concentrations., J Athl Train, volume 49, issue 4, pages 447-53, doi [http://dx.doi.org/10.4085/1062-6050-49.3.12 10.4085/1062-6050-49.3.12], PMID [http://www.ncbi.nlm.nih.gov/pubmed/24933430 24933430]</ref>

<ref name="Phinney-1980">SD. Phinney, ES. Horton, EA. Sims, JS. Hanson, E. Danforth, BM. LaGrange, Capacity for moderate exercise in obese subjects after adaptation to a hypocaloric, ketogenic diet., J Clin Invest, volume 66, issue 5, pages 1152-61, Nov 1980, doi [http://dx.doi.org/10.1172/JCI109945 10.1172/JCI109945], PMID [http://www.ncbi.nlm.nih.gov/pubmed/7000826 7000826]</ref>

<ref name="Schutz-1980">Y. Schutz, E. Ravussin, Respiratory quotients lower than 0.70 in ketogenic diets., Am J Clin Nutr, volume 33, issue 6, pages 1317-9, Jun 1980, PMID [http://www.ncbi.nlm.nih.gov/pubmed/7386422 7386422]</ref>

<ref name="Lambert-1994">EV. Lambert, DP. Speechly, SC. Dennis, TD. Noakes, Enhanced endurance in trained cyclists during moderate intensity exercise following 2 weeks adaptation to a high fat diet., Eur J Appl Physiol Occup Physiol, volume 69, issue 4, pages 287-93, 1994, PMID [http://www.ncbi.nlm.nih.gov/pubmed/7851362 7851362]</ref>

<ref name="Phinney-2011-p31">Phd Stephen D. Phinney MD, Rd Jeff S. Volek Phd, [http://www.amazon.com/The-Art-Science-Carbohydrate-Living/dp/0983490708 The Art and Science of Low Carbohydrate Living: An Expert Guide to Making the Life-saving Benefits of Carbohydrate Restriction Sustainable and Enjoyable], 2011, publisher Beyond Obesity LLC, isbn 978-0-9834907-0-8, Page 31</ref>

</references>

[[Category:Nutrition]][[Category:Science]]

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