Jump to content

The Doctor

Members
  • Posts

    131
  • Joined

  • Last visited

Recent Profile Visitors

The recent visitors block is disabled and is not being shown to other users.

  1. You can start sipping a carbohydrate drink about 20min before the start once you are warmed up. That will prime the stomach and start absorption from the word go. Drink about 200ml total.
  2. Yes. We will be at CWC and ReCycle stands I will be at the CWC stand on Thurs, Fri, Sat afternoons should you want to pop around for any advise.
  3. And I forgot to mention. That last gel is just in case you hit the wall and need emergency supplies.
  4. Best strategy would be 750ml marathon and 750ml carbofuel. Take along 1 bar and 4 gels. Drink the marathon first for 90min then switch. Gels at the end of each hour and 1 in reserve. Bar at halfway point. However, not having trained your gut you might not tolerate the carbohydrate load. In which case it would be better to leave out the bar (which will also be hardest to consume in the bunch). Not sure I'm supposed to tell people to use less of our product but there you have it.
  5. There are really 2 parts to this question that needs answering. 1) Why are you drinking 100g / hr of maltodextrin? Maltodextrin is composed entirely of glucose and max absorption rates in well trained athletes are in the realms of 60g/hr. You are therefore consuming an extra 40g which is just pooling in your GIT and will increase the osmolality, delay fluid absorption and may also cause GI distress (although you don't seem to have any). If you want to consume > 60g/hr you will need to add fructose. 2) Gastric emptying is determined by a complex interaction of fluid osmolality, temperature, composition, volume and other factors. This review will give you a really good overview: http://www.pubpdf.com/pub/24715561/Optimal-composition-of-fluid-replacement-beverages Figure 11 is pertinent, as is the discussion on page 600. To interpret figure 11 look at the % absorbed in 60min. For an 8% solution it is 40% of volume vs 60% of a 4% solution. 40% of 500ml 8% solution = 16g CHO delivered 50% of 500ml 6% solution = 15g CHO delivered 60% of 500ml 4% solution = 12g CHO delivered Although higher CHO concentrations delay gastric emptying, the higher CHO load results in a peak delivery at approximately 8%. Although there are multiple factors that vary this as per the review. 3) Lastly - 500ml x 8% = 40g/hr. Add a gel with 30g and a bar (45g) every 2 hours. You don't need to drink all of the carbs. Solids and gels are absorbed at good rates too.
  6. Bad timing. Gastro the week before the race and then caught a cold on the day. I tried one lap but realised I was doing harm and called it a day.
  7. Current evidence for exogenous ketones as a fuel source is not at all convincing.
  8. Thanks. I appreciate the acknowledgment. As a scientist it is always important to remember that there are absolutely NO scientific facts. There is only scientific consensus. Consensus often changes based on the existing evidence. New evidence -> New consensus. So I keep an open mind and let the data tell us what we currently know to be best practice.
  9. That is a fair interpretation. Just note that you could also do 3 hours of hard riding with a LCHF strategy. However then it would ideally need to be a constant intensity.
  10. That's probably the worst strategy. See above post. Add 2 training sessions each week with carbs and the rest fasted. You will notice a big improvement in races.
  11. The carb / fat question is a very interesting one for which we don't have enough answers yet. We are doing quite a bit of research in this domain at the moment and recently published a paper on this. Link here: https://www.ncbi.nlm.nih.gov/pubmed/26918583 Here is what we know at the moment: During exercise the primary fuel source is carbohydrate. Peak carbohydrate oxidation rates are as high as 8g/min at very high intensities in elite athletes. We used to think that peak fat oxidation rates were always below 1g/min as nobody had ever reported higher than this in any study. Most elite athletes have peak fat oxidation rates of about 0.6g/min When people started banting and also exercising new data emerged that showed that on a LCHF diet, peak fat oxidation rates could reach as high 1.8g/min in a small number of athletes. That is more than twice what we previously thought was possible. This is still quite a few orders of magnitude lower than CHO oxidation rates though. However, that changes our paradigm to some extent with respect to fuelling for endurance sports. A fat oxidation rate of >1.5g/min can sustain an intensity equivalent to approximately 65% of VO2max power. Which is a fairly easonable pace. It is therefore possible to fuel without any carbs for an ultra-endurance event when the pace is not excessively high and is kept constant. A good example would be an age grouper or competitive Ironman athlete on a relatively flat course profile. Things get a little more complicated when you start looking at sports in which the pace varies significantly e.g. road or MTB Habitual LCHF athletes have down regulated CHO absorption rates and also have lower oxidative and glycolytic capacity for CHO. As such, the carbs that they do have stored are not as accessible as they would be in a mixed diet athlete. In addition, they cannot absorb CHO at the same rate as a mixed diet athlete. The study posted above showed that they also do not convert fats or proteins into glucose (gluconeogenesis) at a faster rate than mixed diet athletes. So they are somewhat dependent on fat as a source of energy (or so it seems from our data to date). The upside is that fat is a virtually limitless energy supply and you will therefore never bonk as a LCHF athlete. Many LCHF athletes are completing events like the Ironman on fluids alone. No exogenous fuel! Whether the LCHF diet is a good diet for overall health in the long term is still unclear. So the above points relate solely to performance. The downside is that LCHF can result in greater fatigue in the first few months and may also suppress the immune response. We have unpublished data from ironman athletes that demonstrates higher rates of infections for LCHF athletes than their traditional counterparts. Monitoring fatigue is therefore very important when following a LCHF diet. Adaptation to LCHF as an athlete also takes a few months. It's not something you can switch to overnight. A new strategy that has emerged in recent years is one which attempts to gain some benefit from both fats and CHO. This is know as periodised nutrition. It involves 2-3 fasted exercise sessions each week to stimulate fat oxidation rates. The other 2-3 sessions are down with maximal CHO feeding rates (60-90g/hr) to stimulate the up-regulation of CHO transporters in the gut (training the gut) and to maintain CHO oxidation capacity and glycolysis in the muscle. It also results in a leaner athlete. In races (particularly ultra-distance) the athlete will sometimes fuel with a mix of carbs and fats in the first few hours and then switch to CHO in the last 2 hours. Typical is a Tour De France mountain stage in which the first few climbs are ridden at a lower intensity and then the attacks start to happen on the last climb. With this strategy we can get athletes to achieve fat oxidation rates that are higher than traditional mixed diet athletes but they are still below 1g/min. However, it creates a larger fuel tank while maintaining the ability to perform very high intensity exercise. We are busy writing up data on a LCHF ultra athlete that was tested in LCHF state and again in when using periodised nutrition. The periodised nutrition improved 20km TT power but did not improve 100km TT. So this does confirm our hypothesis to some extent. We will be publishing this data soon. I hope that gives some clarification. We still need to do answer a lot of questions but the science is definitely being conducted and will be published in the coming years.
  12. Sucrose is 50:50 Glucose and fructose So in essence it has the right ingredients but I can't confirm that they are in the right concentration.
Settings My Forum Content My Followed Content Forum Settings Ad Messages My Ads My Favourites My Saved Alerts My Pay Deals Help Logout