Today’s topic is fat loading. Fat loading! Sounds like a dream come true! I envy the athlete who got to be in the research study for that one. When I first heard this my left brain immediately scoffed and dismissed it, but then my right brain said, “Hey David, fat is the primary source of fuel at lower intensities. Would this help for longer distance races?” So, I took a look at the research.

A 2003 study published in Medicine & Science in Sports & Exercise took 11 athletes and had them take in a high fat diet of 53%, and the other group with a low fat diet of only 17% for 5 weeks. Glycogen content was slightly lower in the high fat athletes, but not considered statistically significant. VO2 max was not statistically different between the two groups. Cycling 20 minutes all out, followed by a half-marathon, showed no statistically significant performance decrease in the high fat diet.

Now, I’d like to point out that I am a firm believer in statistics and margin of error, and something being statistically significant or not statistically significant. But if you were to take the times of the top 5 finishers in a Olympic-distance triathlon, and their times are likely only separated by 1 minute or less, and run a statistical analysis on those 5 times, the result would be that there was no statistically significant difference in their times. But, the fact is 1 person was still faster than the other 4. A race director is not going to buy the argument that the second place guy was within the statistical margin of error, and should therefore share first place. So I’m not trying to dilute the importance of statistical analysis but in this study, VO2, glycogen stores, and performance were all just a bit higher in the low fat vs. high fat, although within the margin of error and so in the scientific world there was no difference between the two groups. Perhaps no benefit from fat loading but there was certainly no disadvantage in this study.

In another study from Australia looked at 7 cyclists that took in either a high carb or high fat diet for 6 days, the high fat diet taking in 4.5 times the amount of fat compared to the high carb diet. The researchers found that although there was no difference in performance, the high fat diet used more fat for fuel, which is exactly what you want to train your body to do, specifically for long-distance events.

Finally a 2003 study from the University of Otago in New Zealand seemed to indicate some possible benefit from fat loading on endurance racing. Again, 7 cyclists took in either high fat or high carb diets over a 14-day period followed by a 15 minute time trial and then a 100k (62 miles) time trial. There was a slight decrease in performance in the high fat group on the 15 minute time trial.  But in the 100k time trail, there was a slight increase in power and performance in the high fat group, although the researchers concluded that it was not statistically significant. As in the Australian study, fat was used more for fuel in the high fat group. The researchers concluded that although the main effects were not statistically significant, there was some evidence for enhanced ultra-endurance cycling performance relative to high-carbohydrate.

My opinion on this is that I am not qualified to have an opinion. Seriously, it tends to go against conventional nutrition strategy but convention has been challenged many times in sports physiology to prove what we thought was wrong. What I do know is that no study has shown any performance improvement in fat loading over short distances and only possible improvements over long distance. However, all the studies I looked at failed to tell me the effect on an athlete’s body composition from the fat loading. Did this increase their overall body fat? I can’t imagine that it would not have had some effect on body composition.

Remember that these tests were performed on stationary bikes, so although the performance gains may have been neutral to slight on a stationary bike, any weight gained would not affect the study. Whereas, when cycling outdoors, where you are forced to accelerate your own mass, a 2-pound gain from fat loading would in fact have a negative effect on your performance. I say the jury is still out on this one, there just isn’t enough conclusive proof to do it. If you do choose to try fat loading remember that in the two studies that showed possible benefit for long distance racing, fat loading only took place for the 6-14 days prior to the time trials. Don’t go out and perform a 6 month fat loading plan.

David Warden is a 3-time USAT All American and Elite Coach with Joe Friel's TrainingBible coaching. His work has been published in Triathlete and USA Triathlon Life magazines. He is the former Vice-Chair of the USAT Rocky Mountain Region, and the host and producer of the #1 triathlon podcast, Tri Talk and part owner of  www.powertri.com.

I have some good news if you are a poor swimmer and do short distance triathlon. This news might shatter the psyche of those of you who have been swimming since you were in grade school. You’ll think me some sort of heretic for sharing this information. But, the legendary physiologist Dave Costill has undertaken a great deal of research on swim training over the last 30 years. In one study his team of scientists followed two groups of swimmers over a 25 week training period. Both groups began with once daily training, but one group moved to twice daily training in weeks 10 to 15, reverting to once daily for the rest of the study period. At no stage of the 25 week training period did this group show enhanced performance or increased aerobic capacity as a result of their extra training. Essentially, it was a waste of time.

In another study, Costill tracked the performance of competitive swimmers over a four-year period, comparing a group averaging 10 kilometers per day with a group averaging 5 kilometers per day. Okay, we need to pause right there. 10K of swimming a day!? In relation to changes in competitive performance time over 100, 200, 500 and 1600 yards improvements in swim times were identical for both groups at around 0.8% per year for all events. Again, even though one group did twice as much training, both groups benefited to the same extent in the long term. Holy cow! Costill went on to find that not only does super swim volume not help, but it can actually hurt you by programming too much of your muscle memory to slowtwitch muscles.

Now, I have a real-life experience that backs this up. I have a “friend” who is a bad swimmer. To protect this bad swimmer’s identity, let’s call him, oh, David. My friend David is decent on the bike and run, but I rarely crack the top 50% in swimming in races. I am, or he is, one of those triathletes who comes out of the water and starts to cry when he sees how few bikes are left on the racks. However, two times in the past 3 years David has done an Ironman, with an Olympic distance 5 weeks later. Both were the same races each year. In both Ironmen races, he was not even in the top 50% on the swim. However, in the Olympic distance race he was in the top 25% one year, and in the top 6% of the swim the next year. Top 6% in the swim? Man, David is a stud. So, how could he go from one of the worst to one of the best in just 5 weeks in both years? Now, the initial reaction you may have is that David is simply better at short distances than long, or that all his distance training for Ironman allowed him to perform better at the shorter distance. However, this is inconsistent with the other sprint and Olympic races that were done during the Ironman training, when volumes were high. In those short races during Ironman training with high swim volume, he still came in the bottom 50%, so it mitigates both of those arguments.

Because he was sick of swimming after the Ironman training, he cut his swim workouts to 3 a week, and the first year no more than 2000 meters a day, and for the second year, no more than 1500 meters a day for those 5 weeks. Those 1500-2000 meters a day were done almost exclusively at Olympic distance race pace. There were not even any drills. This is very similar to Costills findings. David simply dropped his volume and increased intensity.

Now, of course, this data and example would only apply to short distance racing. Costill’s data only measured up results of up to 1600 meter races. Obviously, for Ironman racing, you need to be pushing 4000 meters per workout, but for short distance racing, this has a huge impact on where you can consider spending your time when training.

Happy swimming!!

David Warden is a 3-time USAT All American and Elite Coach with Joe Friel's TrainingBible coaching. His work has been published in Triathlete and USA Triathlon Life magazines. He is the former Vice-Chair of the USAT Rocky Mountain Region, and the host and producer of the #1 triathlon podcast, Tri Talk and part owner of  www.powertri.com.