We Were Selected in the Miwok Lottery! YIKES!

We found out on Saturday that we made it into Miwok 100K, and I am excited and a bit terrified. Our first 50 miler was Firetrails 50 last October, after a series of pitiful 50K trail run times (at least for me), and was a purely spontaneous desire for adventure and experience. We made it well enough within the cutoff times, though not at all speedily, and I ended up thinking that I could have gone further if necessary (though I was almost too tired to eat at the end! For me, that’s pretty tired!) So, in principle, this 100K shouldn’t be such a scary ordeal. I think part of the scariness is the fact that I’ve seen these hills up there in the Headlands, and they are not to be trifled with. The other aspect is that this isn’t just spontaneous, we’ve signed up 5 months in advance. That’s 5 months to plan, worry and fret! (oh yeah, and prepare!)

It also brings up the question of what other races to include in the 2009 schedule, and how to train for these events. I’d really like to do a regular street marathon (in a time that doesn’t embarrass me too much) and am considering Napa Valley Marathon on March 1st. But is training for a street marathon compatible with training for Miwok? Inquiring minds want to know (at least this inquiring mind does!) Training for a street marathon, as I understand it, involves training to increase running efficiency and maximize fat burning while flirting with your lactate threshold (a little too fast and you pay a painful price, a little too slow and you, well, take a little longer). Training for Miwok though—that’s trails and hills and trails and hills, ad finitum, well up to about 16 hours worth if you’re near the back of the pack as I suspect I will be, figuring out what gear to use and training your feet and everything else for the challenge. They seem like incompatible objectives. Please feel free to jump in here with advice, though probably at this point it’s too late to make much of a difference anyway…

Another race I’d like to include is the Diablo 50 miler, about two weeks before Miwok. Maybe that’s cutting it too close, I don’t know. I think it depends on how aggressive we are about that race—after Firetrails, I had swollen ankles and legs and was up 3 lbs of fluid for most of a week. But it’s possible we are adapting somewhat because the ankle swelling/weight gain seems to have diminished (no excessive weight gain or ankle swelling after last weekend’s 20 miles through El Corte de Madera and Purisima Creek Redwoods Open Space Preserves—and I wore myself out on those hills and have been sore all week).

In addition to training, running and more running, and oh yeah hills, we are motivated to get back onto a weight loss trend, instead of just holding steady like we have since August. I really don’t want to have to lug an extra ten or twenty pounds for the whole 100K distance. And who knows, we might even get faster too! So this is a good motivator to be more disciplined about our diet. The good news is that there was no appreciable weight gain over the holidays because we were able to mostly stick to low carb eating, even for desserts (yummy truffles and pecan pie heavy on the pecans and light on the sugary filling). I am not disciplined about food, and have enjoyed the low carb/paleo diet because I do not have to be disciplined (unless someone is waving carbs in front of my face). I cannot stand being hungry and feeling deprived. Still, something’s gotta give. David is really getting frustrated—he was down to 185 lbs briefly in the summer, but went back up over 190 after we started ultrarunning (now on a downtrend again). And running more only seemed to make the weight go up a little more. Since our last 50K on December 13th we’ve been taking it easier, taking more rest days and putting in easier distances mostly, shallower hills, moderate heart rate training. But that hasn’t done anything to help get the weight loss going again either. So now we’re going to try to be more cognizant at least of total calories and cheats and see if the weight won’t come off again. Wish us luck!

USDA Food Pyramid Update

The USDA will be updating its food pyramid again next year. At present there is little or no representation from the low-carb community on the panel charged with creating the update. Dr. Michael Eades is soliciting comments to be passed on to the panel on his Protein Power blog. If you are interested in contributing, go to his website and provide a comment. I have reproduced below a comment that I posted there.

Let’s see… populations that have found low-carb diets to have significant health and performance benefits: overweight and obese, diabetic, epileptic, persons at high risk for heart disease, models, actors, endurance athletes (have I missed any?); populations that have problems with low-carb diets: none (unless maybe you count those whose problems are in the form of poor acceptance by family, friends, and coworkers…) But it’s “unproven,” isn’t it? Well, we’d all like to see more extensive data on larger populations. But surely, the obvious failure of current dietary recommendations which HAVE been tested extensively and shown to be seriously flawed, suggests that we need a new approach. Low-carb diets which have shown such clear benefits for so many populations are so clearly superior to the current food pyramid, that we are due for some class-action lawsuits (against the USDA, individual panelists, other medical societies, food industry lobbyists, pharmaceutical companies?) for so blatantly putting self-interests above public health!

My personal story: mid-50s, low-carb for one year after a lifetime of high-carb diets. Used to tolerate high-carb diet well and be able to eat large meals without gaining weight. Weight crept up over time, then started rising faster. Gradual appearance of symptoms of metabolic syndrome (fasting glucose up, blood pressure up, weight up, etc.) Low-carb diet rapidly reversed problems: lost 30 pounds without calorie restriction, blood pressure and fasting glucose down, improved general health and athletic performance (I took up running ultramarathons and now do so on little or no carbohydrates and feel good during and after the events [and I now comfortably run hilly distances of up to about 20 miles/4 hours on no supplemental food at all]). And no, the high level of exercise did not result in my weight loss and health improvement; rather the health improvement and weight loss ENABLED me to increase my level of exercise. If anything, the weight loss has plateaued and reversed slightly with increasing exercise.

It is clear that there are populations that can tolerate and even thrive on high-carbohydrate diets for a lifetime. But my best estimates from data I’ve seen is that these are a minority—probably well under 20% of the general population, and they probably represent predominantly people with either limited access to food and/or people with a high level of daily physical activity.

My recommended changes to general dietary guidelines: start with a baseline of about 20% carbs, 65% fat, 15% protein. Increase carbs only if weight GAIN is needed. Decrease carbs further for weight loss or other specific health conditions such as diabetes. Increase protein if needed for muscle building/repair (athletes). For most people, this sort of diet is best achieved with a lot of meat, fish, nuts, and vegetables, though details can vary widely depending on availability and any religious, cultural, or specific health/allergy issues. Sugars and simple starches should be used sparingly if at all. These include nutritive sweeteners, most wheat, rice, corn, and other grain products. Fruits should also be limited: most are nutritionally predominantly sugar water. Dairy is more controversial. Personally, I do not limit dairy consumption, although some people find it desirable to limit or cut dairy entirely. Legumes and legume products (such as soy products) should probably be consumed in moderation, and may be left out by personal preference. Within these general guidelines, try to eat a wide variety of food.

I think it is most important to focus first and foremost on getting these macronutrient guidelines established and understood. Micronutrients are clearly also important, and since fat is to be recommended as the major source of calories, it is probably also important to recommend emphasizing or avoiding particular types of fat, but these kinds of recommendations should be given a secondary status to the macronutrient recommendations. The “wide variety of food” recommendation should take care of most micronutrient needs for most people.

Training do’s and don’ts

Just for fun, not that we are any kind of expert runners (ha!), we decided to put in our two cents in the TIaRT forum on training do’s and don’ts (I know it’s Friday already!). Some of these thoughts are pretty empirical and based on practical experience over the years, but similar advice is given on the endurancecorner.com training website.

DO:

• Do eat high quality nutrition—limit simple carbs, especially if you are trying to keep the weight off (in contrast to the previous conventional wisdom, you don’t need to replace all 400 to 500 g of glycogen stores everyday in an ordinary training day! We keep our intake to probably <100g, but the absolute amount is up to you and perhaps governed by the intensity of your training). Get plenty of vitamins and omega -3 fats and sufficient protein using fresh veggies and meats/fish/cheese/nuts, including vitamin supplements if necessary.
• Do get sufficient rest–get enough Z’s, take a day off once in a while or just take a walk instead of feeling like you have to run everyday
• Do alternate hard days with easier days and hard weeks with easier weeks
• Do experiment with hill work, tempo training, track intervals, etc. to see how you’re doing under different conditions, and race once in a while just for the feedback and fun
• Do try crosstraining and/or weight lifting to work on specific muscle and core muscle strengthening
• Do make sure you throw in plenty of Goldilocks days (not too hard, not too easy, just the right amount of effort)
• Do evaluate yourself critically and welcome feedback from others, then work on your deficiencies (don’t just gloat about your strengths)
• Do pay attention to what your muscles and joints are telling you. Sore or tired muscles may need to be warmed up more slowly or rested. Extensive stretching before exercise may be losing favor as a routine practice, but if you have a muscle that is tight or tending to cramp, or other problem areas, do stretch it carefully before and after your run.
• Do start slowly. We often find that we don’t “reach our stride” until about 45 minutes or more into a run. Even under race conditions, be careful not to push too hard too early. Do be patient and consistent
• Do use a plan if you’re into it, but I’ve had success (some years ago anyway) just winging it and doing what it seemed needed doing (long runs some days, easy on others, track work to speed up a bit, crosstraining on the bike)

DON’T:

• Don’t overtrain (back off to really easy once in a while–you’ll know when you need it when your legs are just beat or you start to resent your workouts)
• Don’t push through pain all the time—sometimes it goes away if you’re patient, but sometimes it means you need to lay off the hard/long stuff for a while, maybe do some cross training for a week or two or more
• Don’t get discouraged—as the Tao Te Ching says “sometimes things are easy and sometimes things are hard…”. You can be sure that what is hard today will someday be easier, and then again, what is easy today will be hard someday when you’re injured or sick.
• Don’t worry about what other people think— sure you may look like a dork sometimes, we all do, but you can’t try to look great all the time if it means you’re running a pace far too fast to sustain just to impress others. It can mean the difference between a merely respectable time (ok maybe even a poor time) and not even finishing a race.
• Don’t be afraid of a challenge. If you’re not really ready for the challenge, so what? You’ll know what your baseline novice level is and be able to do better next time. Every race, every challenge, will teach you something different about preparation, psychology and equipment that will come in handy later.

One final thought—from reading other contributions on this topic, it’s clear that there is a wide variety of approaches, from those wanting every training detail spelled out to those (like us) just feeling our way along. We haven’t even figured out what races we’re doing this year yet, so it’s hard to begin a training plan! Right now I’m toying with the idea of a road marathon (Napa Valley? Probably haven’t a prayer of a respectable time [i.e., close to finishing times from my distant past], but we may decide to run it anyway just for a baseline number), and we’re waiting to hear about the lottery for Miwok 100K (what the F--- was I thinking?), and of course there’s Diablo 50-miler and some other killer ultra trail events coming up… We’ll see what happens. In the meantime, we’re putting in some easier mileage and watching to see if the heart rate drops with mostly aerobic training as it supposed to do when you’re improving (it does seem to be happening, if slowly). We’re also putting in some tempo runs and track workouts to train for a faster pace that is sub lactate threshold (LT2, as best I can tell where that is—seems to be about 8:30 pace right now for me and maybe 7:30 pace for David) but this is a pace that neither of us can sustain indefinitely. Running on a track is very different from running on trails, especially hilly ones, so we will probably end up incorporating a lot more hills eventually (sure would have helped at Muir Beach!).

Consumer Reports “Secrets of Thin People”

The February 2009 issue of Consumer Reports features an article called “Dieting on a budget, plus the secrets of thin people, based on our survey of 21,000 readers.” The feature includes some equipment reviews, plus articles on “healthful eating on a budget” and their analysis of their reader survey results.

I often find that I disagree with articles and reviews in Consumer Reports, more so whenever I actually have strong personal knowledge of a product or subject area. Their articles are not, of course, peer-reviewed scientific reports. Nevertheless, and despite the fact that they carefully avoid accepting commercial advertising and sponsorship, they typically conform to current industry norms, assuming, I guess, that their readers are responding to the advertising and product offerings they are exposed to and are merely wanting to choose which of the available highly-promoted products to buy. The same can be said of their financial and medical advice in that their advisors (and authors??) seem to be drawn from the mainstream establishment.

There was a time, a few decades ago, when product reviews often used a home-made recipe or similar non-commercial product as a reference for comparison. Quite often, the commercial products did not compete favorably with the non-commercial version. Such comparisons are very rare nowadays. I suppose it, at least partly, reflects the fact that fewer and fewer people are inclined to make their own anything, even when the results are superior. (Though I will admit that there are at least some real examples where modern manufacturing methods make commercial products that are superior…)

Anyway, I digress. In typical fashion, the results of the survey are presented in a way that contains almost no real data and certainly no statistical analysis. Here's what I think are the real “data”:

Survey date: 2007; 21,632 respondents; 66% “overweight” including 22% “obese”

• 16% “never overweight”
• 15% “successful losers” (defined as weighing at least 10% less than at their heaviest and keeping the weight off for at least 3 years)
• 42% “failed dieters”
• 27% other

“more than half” of successful losers did so without the aid of a commercial diet program (defined as a particular medical treatment, book, or pills)

The data get pretty thin after that! The report claims that “through statistical analyses [not presented], we were able to identify six key behaviors that correlated most strongly with having a healthy body mass index.” The standard threshold of 25 is used for defining “overweight,” even though such arbitrary BMI thresholds are well-known to be misleading due to variability in skeletal frame size and muscle development.

The basic conclusion of the study was that successful losers generally embraced the allegedly good behaviors naturally practiced by the always-thin, typically slightly more so, and “significantly” more so than did the failed dieters. Therefore, the authors conclude, all you need to do to be a successful loser is to “quite literally, live like a thin person.”

The six behaviors (“secrets of the slim”) recommended turn out to be current mainstream party-line recommendations:

	Succ. losers	Always thin	failed dieters
watch portions	62%	57%	42%
limit fat	53	47	35
eat fruits and vegetables	49	49	38
eat whole grains	“consistently opted for”		?
eat at home	weight correlated with number of meals out
“exercise, exercise, exercise”*	32	31	23

*while the authors suggested that vigorous exercise that increased breathing and heart rate for 30 minutes or longer was strongly linked to lower BMI, the survey numbers are for strength training at least once per week

The authors note that going low carb is conspicuously absent from the list and that limiting carbohydrates correlated with higher BMI in the survey, though they did note that such a correlation could be an artifact of the fact that those with higher starting BMI are more likely to try a low carb diet. Despite this admission, they still claim that “the findings do suggest that cutting carbs alone, without other healthful behaviors such as exercise and portion control, might not lead to great results.”

They also reported that three other strategies did not show significant effects: eating small meals, never eating between meals. and including lean protein with most meals.

Surveys like this are notoriously unreliable for establishing any true cause-and-effect relationships. It is easy to bias the questions to support the conclusion you want to reach. The conclusion about the ineffectiveness of low carb diets is a good example. If only a small percentage of the survey population had even tried it, then, of course, such a diet would show low significance overall, and therefore no conclusion whatsoever can really be drawn as to the effectiveness of a low carb diet.

Another aspect of the report is the definition of “successful” dieters as those who’ve achieved a 10% weight loss (and kept it off for at least 3 years). For the 22% of respondents characterized as “obese,” 10% is barely a good starting point. At the end of the article, the authors, in a section labeled “Realistic goals are one key to weight loss,” state, “A 10 percent loss might not sound like much, but it can significantly improve overall health and reduce risk of disease.” True perhaps, but pretty discouraging from a public health point of view, if that’s the best we can hope for! And we clearly now know better. There are countless examples of people who have successfully lost much more weight and kept it off (for example, by carbohydrate restriction for those who have demonstrated sensitivity to carbohydrate consumption), and they’ve done it without resorting to extreme methods such as bariatric surgery or starvation diets.

At best, one can use survey data like this to construct hypotheses that might be worth testing. To base public health recommendations on the results is ridiculous!

I look at the data and draw a rather different set of conclusions:

1. We have a serious weight problem if 5 out of 6 people cannot be identified as always thin!
2. Current recommendations don’t work!
3. Even those mainstream recommendations that maybe seem to help don’t help very much.

And I would tend to characterize most of the six “secrets of the slim” as not secrets at all, but just things that are sometimes associated with the habits of people who successfully control weight, and not things that can fix it. Clearly, you can do all six “right” and not lose weight. Yes, overeating (oversized portions, eating out a lot) can make you fat, but it’s much more important what you eat and how you manage what you eat: control of portion size is realistically about controlling hunger and satiety and not about counting calories.

The reported survey benefits of lower fat, higher fruits, vegetables, and whole grains probably just correlate with respondents who are generally attempting to pursue healthful habits, a population who are more likely to exercise self control at earlier signs of a weight problem anyway. Also, the statistics presented do not make a very convincing case that these particular food choices are significantly beneficial; only about half of each survey group practiced any particular allegedly beneficial choice anyway. Hard evidence of benefits of such dietary recommendations are actually thin to non-existent. Exercise is good for overall health, but it's a poor strategy for weight control. Being completely sedentary is correlated with obesity, but it is not a cause. If anything, it’s the other way around: obesity causes people to lead a sedentary lifestyle.

And indeed, one could make a similar argument about causation with respect to the whole survey: always-thin people tend to eat less and exercise more because their body condition makes them so inclined. They are sated with less food and find exercise easier and more enjoyable. Trying to emulate the effect (eating less and exercising more) to achieve the cause (weighing less) doesn't work very well! The authors’ conclusion that all you need to do to be a successful loser is to “quite literally, live like a thin person” gets cause and effect backwards.

We’re improving! Yea!

Well, it seems as if something is improving, albeit slowly. We just completed the Woodside 50K and were pleased to handily beat the cutoff times and bring in a PR (6:31), especially given the difficulty of this course (see profile) relative to our last 50K PR (Skyline-to-the-Sea, previous PR 7:02). The other amazingly cool thing is that I didn’t fall down during this race (though David took a roll instead, thankfully with no injuries). We’ve also benefited from some eye-opening information from using the Garmin 405. Despite its inevitable inaccuracies, it has helped me come to terms with the unpleasant reality of my basic physical condition, what I’m capable of or not, and being realistic about my current status. This allows for focusing on (or trying to focus on, anyway) effective training. Needless to say, I will not be challenging the winners (newcomer Keith Bechtol who smoked the course in 3:36 and destroyed the previous course record of 4:14), but I did come in only ten minutes behind the previous woman in my age group. David was kind enough to pace and encourage me, even though his heart rate monitor revealed that he was consistently performing at a rate about ten beats per minute below mine—in other words, he could have worked a lot harder and gone a lot faster. Thanks Sweetie!

We started out with the pack and just tried to cruise the initial downhill and subsequent climb, which became steeper eventually. David kept telling me I was pushing too hard, and he was right of course—with a heart rate in the mid 160s, I couldn’t sustain that pace the whole way, but I was going to do my best to meet the first cutoff at Bear Gulch (18.9 km, 2:50). We did fine, running up the hills, and slowing to a walk when necessary, and made it to the first aid station (King’s Mtn) about ten minutes faster than I had estimated. I had added an antioxidant tablet (vitamins A, C, and E) and Nuun (for electrolytes) to my water bottle on the way up. (Apparently all the oxidative stress from running generates free radicals that deplete plasma peroxide neutralizing capacity—See for example, the review “Vitamin C for preventing and treating the common cold,” a review of 29 trials involving some 11,000 participants which, while finding minimal effects in general populations, found significant benefit of Vitamin C supplementation in “persons exposed to brief periods of severe physical exercise and/or cold environments.” See also, “Antioxidant supplementation prevents exercise-induced lipid peroxidation, but not inflammation, in ultramarathon runners.”) I added Conquest to the mix at the aid station and guzzled some Coke (for the caffeine and sugar), and tried to choke down a couple of Cliff blocks. There followed the undulating Skyline Trail, deceptively difficult and seemingly unending, before reaching Bear Gulch aid station in 2:30 (well ahead of the cutoff time—I was so thrilled, since our training runs were not so successful). I used one Gu before this aid station, though it’s unclear whether it did any good. By this time, the speedy 35K runners who started 30 minutes after we did had started to pass us—showing us how it is supposed to be done.

The descent into Wunderlich was an enjoyable respite, even though the trail is rough in places and my quads were starting to complain after we’d descended about 1000 feet. We met the front runners heading back up, smiling and making it look easy, and I just tried to keep it steady and not trip or sprain an ankle or something. I trudged back up the hill munching on my sandwich as best I could (it’s hard to eat solid food when there is no saliva!) and washing it down with my antioxidant/electrolyte supplemented sports drink. I conserved energy and fought off an urge to pull over and sleep, and put in some halfhearted jogging at David’s urging. We made it back to the Bear Gulch aid station (33k) by 4:30, and plunged back onto the Skyline Trail for the return trip. The next descent on the Chinquapin trail was heavenly, but they routed us back up the Dean trail (another slow-to-a-walk stretch) before flying down the road to the finish.

I tried to keep up the pace throughout the race, but after a few hours, my body seemed willing to function only at its solid aerobic level (AKA slow). For example, in the descent into Wunderlich, I averaged something like a 9 min mile pace at a HR of 145–150; while during the descent in Huddart I averaged a HR of 140 at the same pace, at least as far as I can tell from my Garmin data, in contrast to the initial part of the race.

What about nutrition during this race? We started out with a Vespa sample that Peter Defty gave us at the Zombie Runner store opening. I supplemented somewhat with carbs (2 Gu’s total, half a ham sandwich, handful of potato chips, few small cups of Coke, sports drink with sugar). I figure since I was pushing into the glycolytic realm (judging by my generally heavy breathing and high heart rate—at least initially, later on I was too tired for that nonsense and HR stayed mostly below 150), I may well be limited by glycogen depletion and some carb supplementation could help. I don’t know that it does, but I did it anyway. David did the entire race on essentially no carbohydrate, using his home-brew protein shake, this time based on coconut milk instead of cow’s milk; he has become a firm believer in running on fat as fuel. Certainly his energy level was more constant than mine (I really wanted a nap on the way back up Wunderlich), but it’s not clear whether that was because I was pushing my limits harder than he was, or his nutrition was superior. I do know that some food is necessary—I’ve experienced nausea with no food (which could, however, be controlled with just a little chicken broth), but I’m not convinced that Gu’s and sugar are really all that helpful.

So what changed? How did our times get better? Since we’ve been doing ultra runs, the weight loss has stalled. I think that some fat loss is still occurring, and there is increased muscle and blood volume and sometimes even swelling and water retention that accounts for some of the stall. But as there has been no further weight loss, that cannot be the reason for improvement. Since the Firetrails 50 miler and SF One Day, we decided it was time to focus on some basic running skills, and actually “train” on occasion. Having run track as a sprinter in my youth, I knew enough to design some simple intervals to see what various paces feel like. It was a pleasant reminder to feel what a 7- or 8-minute pace is like again, and strangely addictive (I want to keep doing it, even though I can’t keep it up for long, unfortunately). We’ve started timing our runs so we can see what might be working, and are including some fartlek segments and some hill sprints in addition to occasional track workouts. I think the most important improvement has come from running on roads, since trail runs inevitably make me stop to walk, if only to admire a beautiful view, or for hills, while road running provides fewer interruptions, allowing you to work on cadence and breathing and consistency, what I’ve been sadly lacking.
So we’ll keep it up and see where it goes!

Slowing with Age?

We started our current diet 10 months ago in an attempt to regain our health and vitality and lose some of the weight that had crept on over the last few years. We appeared to be developing signs of metabolic syndrome despite our frequent hikes, and it was time for more drastic measures. We love the outdoors and hiking, so it was natural to combine hiking/jogging with the low carb diet we began last January. Initially, we did much the same routes as we’d been doing on our casual hikes for the last two years. We gradually increased the challenge of our outings, trying to find ways to connect different parks, no longer being satisfied with the ~8–11 miles available in most parks. At first, these longer outings seemed long and took a lot of time: 12, 15, 18 miles. I experienced my first nausea during and after an 18-mile run/hike (with a couple of thousand feet of elevation change). That just made me mad and I wanted to tackle it again, this time with a bit of food to see if the nausea could be prevented (it worked). Then on a whim, we did our first 50K (Headlands 50K—cool but very hilly), and got seriously addicted to ultra events and pursuit of improved fitness. The first was slow (8.5 hr), which again made me mad and determined to do better. The second (Stevens Creek 50K—see Mark Tanaka’s race report) was worse for me at least (9.5 hr, but very hot and hilly, very low finish rate), though David tolerated the heat much better and did quite well (~7 hr). The third was getting better, but still unacceptably slow (Skyline-to-the-Sea: 7 hr, and net downhill. See Scott Dunlap’s race report). Our fourth ultra was the Firetrails 50-miler which took 12 hours (at least, not a slower pace than previous races; see Jean Pommier’s race report ). Undeterred, a couple of weeks later I ran 49 miles (again in 12 hours at the SF One Day—another painful story).

So why so slow? I’m 52 years old, and seem to have lost much of whatever speed I ever had (a middle of the pack sprinter in high school and college). I was on track for a 3:20 marathon before a calf injury slowed me down—PR of 3:27), now 25 years ago. Just how slow must I be now? Is it possible for a person to regain the health and vigor they had when they were younger? This is the grand experiment, and may fail badly, but that’s the question. Can I get back what I once had? Can I get better? Do I have to be resigned to being old and slow? Can I improve my health while I do it?

So it seems it’s time for some more serious training. We’ve started doing small interval workouts on the track (a few 200s, 400s and 800s) and some tempo runs, just to try to jog the memory of those quiescent fast twitch muscles (no pun intended). I was dismayed to realize that I’ve lost all sprint speed, and running up on my toes feels like I’m going to spazz out and fall on my face. Just doing 400s at an 8-minute-mile pace seems fast at this point. I’m hoping that will change, but how to improve?

Recently, I came across a link to a blog I haven’t discovered before, with an interview with Dr. Maffetone about training for endurance events that was quite interesting. He’s the inventor of the 180 rule (basically subtract your age from 180 to calculate your maximum aerobic heart rate [HR]). According to this method, you train at a level that achieves the desired HR, and you naturally speed up even though you maintain this level of effort, as you train your body to use fat as fuel. In the interview, he describes how he discovered this method basically by measuring respiratory quotients to determine at what HR fat burning occurred as opposed to carbohydrate burning. According to Dr. Maffetone, anaerobic training can be implemented after base aerobic training, in interval workouts or races, then followed by more base training.

I was intrigued and read some of the other advice on his website (sign up for a free membership). His nutrition advice really surprised me as well—another low carber of sorts! He advocates cutting out all refined carbohydrates, much the same advice of the cardiologist Dr. William Davis who is working hard with his patients to prevent and reverse their atherosclerotic disease.

It’s possible that we’ve already achieved a good grounding in aerobic (fat burning) ability, and that now would be a good time to work on speed. Maybe a good test would be to run a regular road marathon to at least get a good baseline number on my starting point. We’ll have to see how it goes…

Carbohydrate Needs of the Endurance Athlete

There is increasing recognition among endurance athletes that at least some fat and protein consumption is beneficial for athletic activity extending beyond about 3 hours. Further, most athletes understand that increased protein consumption post-event is valuable for speeding recovery and reducing discomfort in the following day or two. But most still insist that you
absolutely need plenty of carbohydrates before, during, and after the activity to achieve peak performance, to avoid “crashing” or “bonking,” and to recover quickly. Aid stations are typically stocked almost exclusively with carbohydrates, especially sugars (jelly beans, cookies, M&Ms) and simple starches (potatoes, potato chips, pretzels, gels), with the addition of some limited fats and protein only in the longest events. I’d come to increasingly suspect that this advice is probably wrong, and especially wrong for anyone who has adopted a low-carbohydrate diet and made the physiological adaptation to fat-burning to fuel exercise. I can now add my own anecdotal experience.

I have been restricting my average carbohydrate intake to an estimated 20% or so of calories for about 10 months now. At the same time I have been increasing my exercise level and capability substantially, to the point where I have now completed several 50K running events and one 50-mile event. At first, running seemed harder without the usual high level of carbohydrate intake, but over a few weeks it got steadily easier until fairly suddenly it was much easier. I was able to run uphill again (which I hadn't been able to do for a while); I found my routine breathing rate during comfortable sustained running had slowed by at least a third; I could easily go longer without any food intake besides water.

Nevertheless, for my first 50K event, I consumed more like a 50% carbohydrate meal the night before, and consumed the usual assortment of provided aid station food, avoiding only the simple sugars. The running went well enough, though my weight jumped a few pounds the next day and took three or four days to return to “normal.”

Since then I have been steadily cutting back on carbohydrate supplementation during the run. I did the 50-miler on mostly protein and fat with only a modest amount of carbs thrown in. Then I tried a strict low-carb 50K run, using only a “protein shake” (my own brew of whey protein, soy protein, milk, cocoa, almond meal, and walnut oil) for the entire distance. It worked great! I had steady energy throughout the event (no ups and downs) and was still feeling strong at the end to the point where I did not participate in the post-event food and was happily running around on the beach where the event ended. (The day-after weight gain still occurred; apparently that's not a carbohydrate effect.) So my conclusion is that all this carbohydrate is not needed for successful endurance!

There’s still a question of peak performance. Do you need the carbs and the associated blood glucose spike to do your absolute best? Can you go faster with carbs than without? Does it matter if you’re planning short events (sprints, strength events, etc.) rather than longer endurance events? I don’t know, but I’m increasingly favoring the hypothesis that you don’t actually need much carbohydrate at all once your body is adapted to using fat as its primary fuel.

There are at least a handful of papers related to this topic. These papers all support the idea that only limited amounts of carbohydrates are necessary or even desirable for endurance athletes. See, for example:

Larson-Meyer et al., “Effect of dietary fat on serum and intramyocellular lipids and running performance,” Med Sci Sports Exerc. 2008 May;40(5):892–902 reports 3-day crossover trials of endurance trained runners with low fat (10% fat LFAT) or medium fat (35% fat MFAT), and concludes that “despite approximately 30% lower IMCL [intramyocellular lipids] 0.220±0.032% LFAT, 0.316±0.049% MFAT; P = 0.045) and approximately 22% higher muscle glycogen stores at the start of performance testing (P = 0.10), 10-km performance time was not significantly different following the two diet treatments.” Lipid profiles suggestive of cardiovascular disease were associated with the high-carbohydrate-low-fat diet, and the authors concluded that “even short-term consumption of a low-fat diet may unfavorably alter serum lipids, even in healthy, endurance-trained runners.” (Note that this study did not allow time for adaptation to the different diets, so glycogen and lipid levels in the muscle cells are due only to the acute diets tested);

Vogt et al., “Effects of dietary fat on muscle substrates, metabolism, and performance in athletes,” Med Sci Sports Exerc. 2003 Jun;35(6):952–60, which studied the effect on trained athetes of a high-fat (53% fat) or high-carbohydrate diets (17% fat) for 5 weeks in a randomized crossover design, found that maximal power and vO₂-max during an incremental exercise test to exhaustion were not different between the two diet periods, total work output during a 20-min all-out time trial (298±6 vs 297±7 W) on a bicycle ergometer as well as half-marathon running time (80 min 12 s ± 86 s vs 80 min 24 s ± 82 s) were not different between HF and LF. Blood lactate concentrations and respiratory exchange ratios (RER) were significantly lower after HF than after LF at rest and during all submaximal exercise loads. The authors concluded that “muscle glycogen stores were maintained after a 5-wk high-fat diet period whereas IMCL content was more than doubled. Endurance performance capacity was maintained at moderate to high-exercise intensities with a significantly larger contribution of lipids to total energy turnover”;

Lambert et al., “High-fat diet versus habitual diet prior to carbohydrate loading: effects of exercise metabolism and cycling performance,” Int J Sport Nutr Exerc Metab. 2001 Jun;11(2):209–25. No changes were observed in circulating glucose, lactate, free fatty acid (FFA), and b-hydroxybutyrate concentrations during exercise. However, mean serum glycerol concentrations were significantly higher [indicating mobilization of fat stores with glycerol release] in the HFD-CHO trial. The HFD-CHO diet increased total fat oxidation and reduced total CHO oxidation but did not alter plasma glucose oxidation during exercise. By contrast, the estimated rates of muscle glycogen and lactate oxidation were lower after the HFD-CHO diet. The HFD-CHO treatment was also associated with improved time trial times (29.5±2.9 min vs. 30.9±3.4 min)[150 min cycling at 70% vO₂-max followed by a 20 km time trial] for HFD-CHO and CTL-CHO. They conclude that “high-fat feeding for 10 days prior to CHO-loading was associated with an increased reliance on fat, a decreased reliance on muscle glycogen, and improved time trial performance after prolonged exercise”;

Leddy et al., “Effect of a high or a low fat diet on cardiovascular risk factors in male and female runners,” Med Sci Sports Exerc. 1997 Jan;29(1):17-25, which notes that “restricting fat intake may compromise endurance performance and that increasing fat intake may improve endurance performance,” and concludes that “a 42% fat diet maintained favorable CHD risk factors in female and male runners whereas a 16% fat diet lowered Apo A1 and HDL-C and raised the TC/HDL-C ratio”;

Horvath et al., “The effects of varying dietary fat on performance and metabolism in trained male and female runners,” J Am Coll Nutr. 2000 Feb;19(1):52–60, which concludes that “runners on a low fat diet consume fewer calories and have reduced endurance performance than on a medium or high fat diet [and] a high fat diet, providing sufficient total calories, does not compromise anaerobic power.”