Hi Dr. Wilson,
I have found your nutrition book for endurance athletes to be the number one resource for my triathlon nutrition. Thank you so much for all your efforts in this realm. There are a couple of topics that I could use a little more explanation on, if you have a moment.
1) I'm a little confused on the calorie consumption part, while racing or training. In the advanced
nutrition chapter, you write about lean tissue and multiplying it to get the amount of calories you
should consume per hour. So, is it your overall weight X2 or your lean tissue ((i.e. body weight X lean tissue...175 lbs. X .95% (I have 5% body fat))? Could you explain a little more here?
ANSWER: Hi Nick. "Lean" body weight corresponds to your body weight if you have the same body fat levels as the competitive triathletes used in the studies estimating the maximum caloric uptake during intensive training. Thus, at 5% body fat, your full body weight is your "lean" body weight. Normally you would be correct about using 95% of your weight to get the weight of only your lean tissue, but in this case leaness is relative to the individuals in the study, who had roughly the same body fat levels as you do. Most people will not know their exact body fat (I don't know my exact body fat levels) so I simply estimate my "lean" body weight as being 5-10% lower than my current body weight (I do not do nearly as much endurance training as a competitive triathlete and do much more strength training, so my body fat levels are higher than those of the triathletes used in the study).
2) You say on efforts lasting over 3 hours, eat twice as many calories and have the new calories be solid food. What about a half-ironman? That's longer than 3 hours, but less than 3.5 hours on the bike. Wouldn’t stomach upset be an issue on the run?
ANSWER: Anything over the maximum number of calories in the form of rapidly-digesting carbohydrates discussed in your first question (above) should be consumed as solid food since the lean body weight calculation tells you how much rapidly digesting calories can be utilized at high intensity training, and beyond this amount you want calories to enter the body slower. The longer a competition gets, the lower the relative intensity throughout the race, meaning that digestive function is higher and you can absorb more calories into the bloodstream. There is no need to take in extra calories as solid food if your hunger levels do not go out of control during a longer race. But many endurance athletes get so hungry after 3, 4 or 5 hours of racing that they end up eating a couple energy bars all at once, spiking their blood sugar and reducing their performance. If your experience is that hunger like this does not occur for you, there is no reason to eat anything in addition to the base-line (rapidly-digesting) calories. However, if your experience is that you do need to satisfy hunger during a longer race, use solid food (nut butter sandwich, broken up pieces of an energy bar containing some whole grains, etc), consuming it in parts every 15 to 20 minutes starting before your hunger drives you to over-consume at any one time.
3) I'm assuming I should only consume solid food during Ironman (IM) on the first part of the bike, and not the entire time because of the run, so when would I stop eating solid foods and just take in malto?
ANSWER: This is based on your digestive system and how well you hydrate on the bike. If you maintain your normal body weight on the bike (i.e. consume suffient fluid, being careful to not over-drink i.e. never gain weight during training or competition!), you can consume small regular amounts of solid food up until shortly before the run and not likely have any problems. I know triathletes that can eat solid food DURING the run phase, and I know others who's digestive system is so sensitive that they have a hard time with solid food even in the beginning of the bike phase. Let your personal experience be your guide here, meaning note what has worked in past races and during your training bricks, keeping in mind that you can be more bold (eat solid food closer to the start time of the run) when your hydration is on target.
4) Lastly, do you recommend any type of supplement that adds antioxidants, acid-buffers or amino-acids while racing? There are many products out there to add to your malto, but I'm not sure what the scientific benefits of them are. I notice you didn't mention anything about this, so I'm assuming they don't do much.
ANSWER: You are correct about them not doing much. The research is almost entirely mute on the subject in terms of benefits of antioxidants or buffers, and benefits of protein intake during training have been shown to be minimal (see my "protein supplementation" thread). The only conclusion we can draw right now, if you assume that the studies thus far were done by competent labs (which I think is a reasonable assumption), is that the benefits are too small to see. In theory amino acids, acid buffers and antioxidants should all help, but it appears that they provide their significant (measureable) benefits when they come from natural foods during recovery. In other words, cortisol breakdown of muscle to get protein during exercise is not reduced significantly during training with amino acid intake, antioxidant intake during exercise is not of enough variety when taken in supplement form (as opposed to food) to properly combat all the types of free radicals produced during training and that the rate of free radical production is extremely high during intensive training, and that while acid buffers help in theory the relative impact on muscle function is too low to warrant their use. If I ever see anything more supportive of these items I will certainly post it.
5) I have found that GU's drink (with a little added sugar) has the right ratio of complex to simple carbs you talked about, so I've been using it on the bike. Thank you so much for the great advice. I have IM California coming up and am excited to try me new and improved nutritional program (I bonked hardcore at CDA last year). The Clyde Shake is the only breakfast I've ever used that hasn't given me an upset stomach during a race. Thanks! Nick
NICK: Thanks for your feedback!
Comments