Tag: Substrate Metabolism

Low Carb High Intensity Interval Training Performance

Here’s a new study that looked at the Low Carb diet and High Intensity Interval Training performance (Lukas Cipryan, Daniel J. Plews, Alessandro Ferretti, Phil B. Maffetone, and Paul B. Laursen. Effects of a 4-Week Very Low-Carbohydrate Diet on High-Intensity Interval Training Responses. J Sports Sci Med. 2018 Jun; 17(2): 259–268.).

The purpose of the study was to examine the effects of altering from habitual mixed Western-based (HD) to a very low-carbohydrate high-fat (VLCHF) diet over a 4-week timecourse on performance and physiological responses during high-intensity interval training (HIIT).

Eighteen moderately trained males (age 23.8 ± 2.1 years) consuming their HD (48 ± 13% carbohydrate, 17 ± 3% protein, 35 ± 9% fat) were assigned to 2 groups. One group was asked to remain on their HD, while the other was asked to switch to a non-standardized VLCHF diet (8 ± 3% carbohydrate, 29 ± 15% protein, 63 ± 13% fat) for 4 weeks.

Participants performed graded exercise tests (GXT) before and after the experiment, and an HIIT session (5x3min, work/rest 2:1, passive recovery, total time 34min) before, and after 2 and 4 weeks. Heart rate (HR), oxygen uptake (V̇O2), respiratory exchange ratio (RER), maximal fat oxidation rates (Fatmax) and blood lactate were measured. Total time to exhaustion (TTE) and maximal V̇O2 (V̇O2max) in the GXT increased in both groups, but between-group changes were trivial (ES ± 90% CI: -0.1 ± 0.3) and small (0.57 ± 0.5), respectively.

Between-group difference in Fatmax change (VLCHF: 0.8 ± 0.3 to 1.1 ± 0.2 g/min; HD: 0.7 ± 0.2 to 0.8 ± 0.2 g/min) was large (1.2±0.9), revealing greater increases in the VLCHF versus HD group. Between-group comparisons of mean changes in V̇O2 and HR during the HIIT sessions were trivial to small, whereas mean RER decreased more in the VLCHF group (-1.5 ± 0.1). Lactate changes between groups were unclear.

Adoption of a VLCHF diet over 4 weeks increased Fatmax and did not adversely affect TTE during the GXT or cardiorespiratory responses to HIIT compared with the HD.

I have a lot of respect for Phil Maffetone and Paul Larson. Both are long time advocates of Low Carb Athletics. Phil Maffetone coached Mark Allen to multiple wins at Kona Ironman (Mark Allen Interview: A look back at working with Phil Maffetone and what it means for today’s triathlete).

 

 

MCT Oil and Athletic Performance

I read a post by a guy in a Facebook group who claims MCT oil increases his athletic performance. I questioned him and he wrote:

However, when the body fat percentage gets low, you need the fats for energy to fuel your workouts. You have to reach steady state of fat in and fat/ketones out. I don’t think I could do my noon workout without my two cups of BPC in the morning. That’s my fuel…

When I asked if it was the MCT oil or the caffeine he replied:

… it’s the fat. Caffeine does not give you the ketones that allow me to lift heavy and do 30-45 mins of elliptical. Although, when I was very fat, my body provided the fat ketones. So in a sense I’m agreeing with you. There comes a time when you need that MCT fat that the liver turns into ketones as a priority.

Unfortunately the science doesn’t back up the claims.

Study #1

Miriam E. Clegg. (2010). Medium-chain triglycerides are advantageous in promoting weight loss although not beneficial to exercise performance. International Journal of Food Sciences and Nutrition, 61:7,653-679.

Results indicate that MCT feeding is ineffective in improving exercise performance and future work should focus on the health benefits and applications of MCT.

Study #2

Damien J. Angus, Mark Hargreaves, Jane Dancey, and Mark A. Febbraio. Effect of carbohydrate or carbohydrate plus medium-chain triglyceride ingestion on cycling time trial performance. Journal of Applied Physiology. Volume 88 Issue 1. January 2000. Pages 113-119 .

These data demonstrate that carbohydrate ingestion during exercise improves 100-km TT performance compared with a sweet placebo, but the addition of MCT does not provide any further performance enhancement.

Study #3

A E Jeukendrup, J J Thielen, A J Wagenmakers, F Brouns, W H Saris; Effect of medium-chain triacylglycerol and carbohydrate ingestion during exercise on substrate utilization and subsequent cycling performance. The American Journal of Clinical Nutrition, Volume 67, Issue 3, 1 March 1998, Pages 397–404.

…ingestion of MCT had a negative effect on performance…

compared with placebo ingestion, MCT ingestion had no effect on total rates of fat or carbohydrate oxidation, nor did it affect exogenous or endogenous carbohydrate utilization. The negative effect of MCT ingestion was associated with increased gastrointestinal complaints (ie, intestinal cramping). These data suggest that large amounts of MCTs (85 g) ingested during prolonged submaximal exercise may provoke gastrointestinal problems leading to decreased exercise performance.

Study #4

Jeukendrup, A. E., A. J. M. Wagenmakers, F. Brouns, D. Halliday and W. H. M. Saris. Effects of carbohydrate (CHO) and fat supplementation on CHO metabolism during prolonged exercise. Metabolism 45(7): 915-921: 1996.

It is concluded that 29 g MCT co-ingested with CHO during 180 minutes of exercise does not influence CHO utilization or glycogen breakdown.

Other Studies

Another study found that MCT Oil increased liver size by adding fat to the liver (MCT Oil and Liver Size).

Ketogenic Ironmen

Nice short study on Keto and Ironman ultra-endurance events (Maunder E, Kilding AE, Plews DJ. Substrate Metabolism During Ironman Triathlon: Different Horses on the Same Courses. Sports Med. 2018 May 18. doi: 10.1007/s40279-018-0938-9.).

Given the finite human capacity for endogenous carbohydrate storage, minimising the endogenous carbohydrate cost associated with performing exercise at competitive intensities should be a goal of Ironman preparation. A range of strategies exist that may help to achieve this goal, including, but not limited to, adoption of a low-carbohydrate diet, exogenous carbohydrate supplementation and periodised training with low carbohydrate availability.

Given the diverse metabolic stimuli evoked by Ironman triathlons at different performance levels, it is proposed that the performance level of the Ironman triathlete is considered when adopting metabolic strategies to minimise the endogenous carbohydrate cost associated with exercise at competitive intensities. Specifically, periodised training with low carbohydrate availability combined with exogenous carbohydrate supplementation during competition might be most appropriate for elite and top-amateur Ironman triathletes who elicit very high rates of energy expenditure.

Conversely, the adoption of a low-carbohydrate or ketogenic diet might be appropriate for some lower performance amateurs (> 12 h), in whom associated high rates of fat oxidation may be almost completely sufficient to match the energy demands required.

Nicely put.

 

BCAAs – Second Experiment

I did a second experiment with BCAAs today. The last one was at a Crossfit competition (CrossFit Competition – Festivus Games). There was so much going on that day that I didn’t get a chance to compare the BCAA effects. I was also using Ketone Supplements that day so I could not isolate any effects.

This morning, before my MAF walk, I decided to try the second serving of BCAAs. They were given to me by athlete Van Wilder. I took them with Creatine in water before leaving the house around 5:30 AM. The product is Optimum Nutrition Essential AmiN.O. Energy. Here’s a picture of the product.

Here is the nutrition label.

These have as much caffeine as a cup of coffee but they are taken in much more quickly than coffee. I definitely noticed a buzz from the caffeine. I also had some strange data from my heart rate monitors. I also had some soreness/pain in my left knee so I took it a bit easier as documented here(Measuring Heart Rate).

I can’t say whether there was an effect beyond the caffeine effect.

In the meanwhile I ordered another product as recommended by Ben Greenfield (Everything You Need To Know About How To Use Amino Acids For Muscle Gain, Appetite Control, Injury Repair, Ketosis And More.) Ben provides some compelling arguments for why BCAAs (Kion Aminos) may be a good choice for fasted workouts with ketogenic athletes.  There are quite a few studies referenced on Ben’s page.

The Other Side

On the other side, Menno Hensellmen has some arguments against BCAAs and refers to this study for his position (Robert R. Wolfe. Branched-chain amino acids and muscle protein synthesis in humans: myth or reality?
Journal of the International Society of Sports Nutrition 2017 14:30).

An extensive search of the literature has revealed no studies in human subjects in which the response of muscle protein synthesis to orally-ingested BCAAs alone was quantified, and only two studies in which the effect of intravenously infused BCAAs alone was assessed. Both of these intravenous infusion studies found that BCAAs decreased muscle protein synthesis as well as protein breakdown, meaning a decrease in muscle protein turnover. The catabolic state in which the rate of muscle protein breakdown exceeded the rate of muscle protein synthesis persisted during BCAA infusion. We conclude that the claim that consumption of dietary BCAAs stimulates muscle protein synthesis or produces an anabolic response in human subjects is unwarranted.

I will report on the BCAAs.

 

Dietary Periodization – Strategic Carbs

Do Strategic Carbs work?

This study took a look at the strategic carbs strategy (Louise Burke. Fat adaptation and glycogen restoration for prolonged cycling—recent studies from the Australian Institute of Sport. Australian Journal of Nutrition and Dietetics, vol. 58, no. 2, 2001, p. S23+). The study looked at:

… a period of exposure to high fat, low CHO intake, followed by the restoration of muscle glycogen stores with a high CHO diet.

Such ‘dietary periodisation’ aims to enhance the capacity of both glycolytic and lipolytic systems to oxidative metabolism during prolonged exercise, by increasing the contribution from fat to substrate metabolism while potentially sparing intact muscle glycogen stores

Here are the results:

The fat adaptation diet caused major changes in fuel utilisation during sub-maximal exercise, with at least some of the adaptations persisting on day seven, even in the face of a plentiful CHO supply. As dramatic as these metabolic changes were, they failed to improve the performance of the cyclists’ time trial.

Together with other research, this study fails to find evidence that fat adaptation strategies offer any benefits for the endurance athlete.

The only remaining question is whether there are any advantages for ultra-endurance athletes who compete in events undertaken at a lower intensity and for longer periods (e.g. four hours or more). For these athletes, fat is the predominant fuel source.

 

Quality of Protein Matters for Muscle Protein Synthesis

A 2012 rat study that shows not all protein is of equal quality when it comes to Muscle Protein Synthesis (Norton LE1, Wilson GJ, Layman DK, Moulton CJ, Garlick PJ. Leucine content of dietary proteins is a determinant of postprandial skeletal muscle protein synthesis in adult rats. Nutr Metab (Lond). 2012 Jul 20;9(1):67. doi: 10.1186/1743-7075-9-67. ).

…only whey and egg groups increased post-prandial plasma Leu and stimulated MPS above food-deprived controls. Likewise, greater phosphorylation of p70 S6 kinase 1 (S6K1) and 4E binding protein-1 (4E-BP1) occurred in whey and egg groups versus wheat and soy groups. Experiment 2 demonstrated that supplementing wheat with Leu to equalize the Leu content of the meal also equalized the rates of MPS.

Protein Before Bed

Here’s an interesting study which indicates that Protein taken before bed stimulates Muscle Protein Synthesis (Tim Snijders, Peter T Res, Joey SJ Smeets, Stephan van Vliet, Janneau van Kranenburg, Kamiel Maase, Arie K Kies, Lex B Verdijk, Luc JC van Loon; Protein Ingestion before Sleep Increases Muscle Mass and Strength Gains during Prolonged Resistance-Type Exercise Training in Healthy Young Men, The Journal of Nutrition, Volume 145, Issue 6, 1 June 2015, Pages 1178–1184).

Methods: Forty-four young men (22 ± 1 y) were randomly assigned to a progressive, 12-wk resistance exercise training program. One group consumed a protein supplement containing 27.5 g of protein, 15 g of carbohydrate, and 0.1 g of fat every night before sleep. The other group received a noncaloric placebo. Muscle hypertrophy was assessed on a whole-body (dual-energy X-ray absorptiometry), limb (computed tomography scan), and muscle fiber (muscle biopsy specimen) level before and after exercise training. Strength was assessed regularly by 1-repetition maximum strength testing.

Results: Muscle strength increased after resistance exercise training to a significantly greater extent in the protein-supplemented (PRO) group than in the placebo-supplemented (PLA) group (+164 ± 11 kg and +130 ± 9 kg, respectively; P < 0.001). In addition, quadriceps muscle cross-sectional area increased in both groups over time (P < 0.001), with a greater increase in the PRO group than in the PLA group (+8.4 ± 1.1 cm2 vs. +4.8 ± 0.8 cm2, respectively; P < 0.05).

Both type I and type II muscle fiber size increased after exercise training (P < 0.001), with a greater increase in type II muscle fiber size in the PRO group (+2319 ± 368 μm2) than in the PLA group (+1017 ± 353 μm2; P < 0.05).

Getting Van Wilder to Boston

The Big Question Remains

How to best fuel Van Wilder’s (Another VO2max Test – Van Wilder) next marathon? It is six weeks away and he’s not far from qualifying for the Boston Marathon. Is it best to shift to a high carb low fat diet for the marathon?

Pace vs Heart Rate Test

We did a test of pace vs heart rate.  The test was done on a track in 800 meter distance increments with speed matched to 10 bpm heart rate steps every 2 laps (of the 400 meter track). We downloaded the average data from the logging application.

We then overlaid the pace vs heart rate data with fat-carb oxidation rates from Van Wilder’s VO2max test. Here’s the resulting curves:

The top curve is running pace. Van Wilder’s fastest pace was almost a 4 minute mile. At that rate, he was have been oxidizing around 22 calories of carbs and 9 calories of fat per minute. The rate is also not sustainable due to the high exertion required.

Van Wilder has to run the marathon in about 3 hours. That’s 26.2 miles/3 hrs = 8.7 mph. That’s 60 min/hr divided by 8.7 miles/hr = 6.9 minutes per mile. That’s a heart rate of 155. That is also around 15 calories per minute from carbs and 12 calories per minute from fat. 15 kCal/min * 60 mins = 900 kCal/hr. If he can feed 360 kCal/hr from carbs that’s a net of 540 lost per hour. In three hours his muscle glycogen will be completely gone (assuming it can all be used).

Probably can’t get there from here – at least at the current performance.

Update 2018-09-14

Van Wilder suffered a hip injury and had to drop out of his qualifying marathon last week. That was the last chance for the season.

 

Athlete Van Wilder – Part 2

In an earlier post, I took a look at Van Wilder (Another VO2max Test – Van Wilder). He was a low carb guy but has bumped up the carbs. quite a bit. The day before the VO2max he ate quite a few carbs.

Let’s look close to see if our VO2max curves are comparable to the Volek FASTER chart. Here’s the FASTER chart:

The HCD (High Carbohydrate Diet) looks like an inverted parabola and can be modeled as a 2^X function. Due to the distorted hump, the LCD (Low Carbohydrate Diet) looks like a higher order polynomial (more than a square = 2nd order). Assuming a 3rd order polynomial would model the curve better. Revisiting the VO2max data for Van Wilder (as a third order polynomial):

Here is my VO2max data (also as a third order polynomial):

My curve looks more shifted to the right similar to the FASTER graph. Both of the graphs have the same 50%-50% calories point at about 80% of VO2max.

Van Wilder’s MFBGS (Maximum Fat Burning Glucose Sparing) point is at around 43% of his VO2max. My own MFBGS is quite a bit higher at around 61% of my VO2max. Does that provide any real advantage? Certainly my 20+ years older doesn’t help me out.

Van Wilder’s MAF Number

Van Wilder is a well trained athlete but he’s constantly injured. He should have a reduced MAF number but let’s assume he’s at the 180 – 35 = 145 heart rate.

Van Wilder’s MFBGS point is at around 118 bpm. At his MAF number he’s well into carbohydrate burning (around 65% fat and 35% carbs).

 

Train Low, Compete High

One popular Low Carb strategy is to train low and compete high. The basic strategy is to do all training in a fat adapted state and then switch to a higher carb state a day or two before competition.  A study took a look at this methodology (Havemann L, West SJ, Goedecke JH, Macdonald IA, St Clair Gibson A, Noakes TD, Lambert EV. Fat adaptation followed by carbohydrate loading compromises high-intensity sprint performance. J Appl Physiol 2006 Jan;100(1):194-202.). The study consisted of six days of High Fat diet to a High Carb diet on the 7th day. The study looked at the performance on the 8th day. The purpose of the carb fueling was to fill glycogen stores before the final tests.

The ingestion of a HFD for 6 days resulted in a shift in substrate metabolism toward a greater reliance on fat and a reduction in CHO oxidation. The increase in fat oxidation in the present study persisted despite 1 day of CHO loading on day 7 as demonstrated by the lower resting RER (0.77  0.02 vs. 0.88  0.05, Fig. 2) and higher circulating FFA (Table 7) during exercise after HFD-CHO compared with HCD-CHO on day 8.

Here’s what was valuable about this 2006 study.

The study is unique in that it is the first study to investigate the effect of high-fat feeding, followed by CHO loading, on endurance exercise, including high-intensity sprints that simulate actual race situations.

In spite of being on a High Carb diet the effects of the High Fat diet persisted. This could be seen in a lower RER value indicating increased fat oxidation. However, the sprint performance was not as good. From the discussion:

It was hypothesized that the potential glycogen-sparing effect of this dietary strategy (3) would be most beneficial for exercise that included high-intensity sprint bouts, where muscle glycogen is the predominant fuel. However, in contrast to our hypothesis, the HFD-CHO strategy actually compromised high-intensity 1-km sprint performance.