May 25 2023 xx
The low-carb lowdown: It increases risk of death
An impressive new nutrition study reports on mortality risks/benefits of a low-carb diet vs a low-fat diet. The investigation tracked more than 371,000 adults (ages 50-71) over a followup period of 23.5 years. During that time, 165,000 of the subjects died. That’s a nice, big number to dive into.
The two contrasting diets have mainly been researched in terms of weight loss, where both have been found successful in different studies with different subject groups. But these studies rarely last more than 6 to 24 months.
What about the long-term health effects of the two diets? That’s what everyone has been wanting to know.
Results from the new paper: Those who most closely followed a low-carb (and therefore high-fat) diet had a 12 to 18% greater risk of “total and cause-specific” mortality ” vs the study’s average risk. Conversely, those on the strictest low-fat diet had a 16 to 18% lower risk.
The outcome included an important wrinkle of the type you can only find in a truly massive study like this one. If the low-carb eaters consumed healthy fats rather than saturated fats, they had a 5% lower-than-average mortality rate.
So you can eat healthy on a low-carb diet provided you pay attention to the types of fat in your meals. Stay away from the greasy fried foods and meats marbled with saturated fat.
Conclusion: “Our results support the importance of maintaining a healthy low-fat diet with less saturated fat in preventing mortality among middle-aged and older people.” More at J of Internal Medicine with free full text.
The ultimate carbohydrate-loading plan
Let’s say you’re a serious runner who regularly consumes a high-carb diet to sustain your training. You’ve got a marathon coming up, and you’re planning to eat even more carbs because that’s supposed to increase your muscle glycogen supply, and help you perform better.
But is that realistic? Given that you’re already consuming a high carb diet basically every day, will eating even more carbs actually make any difference?
Yes. That’s the outcome from a new report that investigated this very scenario in a case study. “We found that a 2-day very-high-carbohydrate diet and tapering of training could further increase the muscle glycogen concentration in athletes.”
That’s the good news.
The study followed an elite race walker who consumed a consistent high-carb diet to sustain his training. He then tested three different super-carb-loading plans during a 2-day taper of his training. The goal: To see which of the three carb programs produced the greatest increase in his leg glycogen supply.
The three plans could be loosely described as: Eat a big breakfast; focus more on gels and snacks throughout the day; and pig out on every carb in sight.
The precise amount of carbs consumed in the three trials was 13.7 grams/kg body weight, 13.9 grams, and 15.9 grams. (Experts often recommend 6 to 12 grams/kg body weight when carb loading.]
For our test subject, more was better. The three plans pumped up his thigh-muscle glycogen by 47.1 millimoles vs 82.8 vs 117.2. His body weight increased on all three plans, as did his total body water.
So, yes, you can increase your muscle glycogen supply even if you’re already consuming a lot of carbs every day. The “taper” is super critical in this regard. And you get the best technical results by stuffing your face all day long.
But … there’s a big “but.” It’s not as much fun as it sounds. Indeed, the test subject “experienced stomach discomfort throughout the day.” And the researchers concluded that 15.9 grams/kg body weight “was too high to be used before an actual race.”
Instead, prior to his next important competition, the athlete decided on a modestly lower plan, 14.5 grams. The paper does not report his race result. More at Physical Activity & Nutrition with free full text.
Hop to it: Boost your running economy with simple hopping exercises
RLRH has recently looked at several studies on strength training, plyometrics, and simple hopping exercises for improved running performance. Now the Sweat Science guy, Alex Hutchinson, has weighed in with his perspective.
Hutchinson notes that there’s good evidence for strength training and plyometrics, but not that many adherents, probably because the sessions seem intimidating. Also, they might lead to injury, so it’s easy to talk yourself out of them. Too bad there’s not an simpler way.
That’s where hopping comes into play. Several papers have shown that relatively simple hopping exercises can boost your tendon stiffness (particularly of the powerful Achilles tendon) enough to increase your running economy. And the hopping didn’t lead to injuries either. More at Outside Online.
What’s the best time of day for optimal training?
Many of us don’t have much latitude with regard to the time of day when we train. After all, family, work, and other obligations are often the first concern. But we’re still interested in the question: Does time of day of training have an influence on our health and fitness gains?
The authors of this new paper say they are the first to investigate the question with a systematic review and meta analysis. Note that they weren’t primarily interested in time of day of best performance. That’s generally agreed to be the late afternoon. Rather they were looking for the best time to train to improve performance.
However, they couldn’t reach a conclusion that was “generalizable or consistent across studies.” For example, training to increase vo2 max proved “independent of the time of day at which the training” was performed. So it appears your training can be effective whenever you manage to squeeze it in.
With this important caveat: If you train at a certain time of day, that will become the time when you are most efficient. If you’ve got an important early-morning race on the horizon, you’d better get up to run early on several occasions. Your body likes routine, and dislikes being shocked out of its normal routine. More in Sports-Medicine Open with free full text.
Tendon injury? Here’s unexpected advice: Lift heavy
Two new papers on tendon injuries provide advice you can use to prevent and recover from these nagging issues at the Achilles and around the knees.
A study of almost 2000 Dutch runners found that about one-third had experienced a tendon injury at some time. Achilles tendinitis was the most common problem. Others included patella tendinitis and plantar fasciitis. Men had more tendon injuries than women, possibly because they ran more miles and harder, and raced more often. However, the sex association persisted after the researchers made statistical corrections for training and body weight.
Among women only, there was an interesting link between soft surface running and tendinitis. The soft surfaces increased tendon-injury incidence.
While earlier studies (mainly in animals) had uncovered certain nutritional associations between diet and tendinitis, this human study revealed none. This could have been because the subjects followed a largely high-quality diet. More at BMJ Open Sport & Exercise Medicine.
If you do develop a tendon injury, you have to decide on a recovery program. A new systematic review and meta analysis of such programs included 110 studies with a pooled total of 3900 subjects. It reported that “Exercise therapy is the main mode of conservative treatment for tendinopathies with a focus on resistance exercise, which is shown to be effective in improving patient outcomes.”
This leads directly to the question of low weights vs high weights? And the answer might not be what you’re thinking, as heavier weight programs were more successful, provided they allowed for adequate rest. That is, avoid low-weight programs that include multiple sets per day.
Conclusion: The most successful programs prescribed “higher intensities (through inclusion of additional loads) and lower frequencies, potentially creating stronger stimuli and facilitating adequate recovery.” More at British J of Sports Medicine with free full text.
When to lose weight (for performance), and when not to bother
Every sport and situation is different. Swimming is one thing--weight loss doesn’t help much. Running is another case--often, it does (in the short term). And cycling is practically two different sports. If you want to go hard on the hills, less weight is better; when sprinting on the flats, you want more power (likely from more strength and weight).
This is what makes the Tour de France so fascinating. You need to be both a great mountain climber and a great time-trialer. It’s not easy to combine the two.
This coach’s guide starts with the important warning that prolonged low calorie intake can have negative outcomes, including bone stress injuries and more. It notes that many smart coaches “want to make their athletes as anti-fragile as possible.” That new term is gaining popularity among endurance athletes: “anti-fragile.” Also, if an “athlete has a healthy weight and primarily races on flat or rolling courses, the energy deficit required for weight loss probably isn’t worth the risk.”
Finally, it explains how the laws of physics can help you decide if weight loss might prove beneficial on a particular race course. More at Training Peaks.
It’s got a weird name, but Coenzyme Q10 can boost your immunity
I’ve tried a lot of different supplements over a lot of years, and soon drifted away from all of them but Vitamin B-12, as I follow a mostly-vegetarian diet, and have several times blood-tested low for B-12. I just couldn’t be bothered to continue with any others, plus I never felt any difference from using them.
One supplement I’ve never tried: Coenzyme Q 10. The name is weird, and I never understood what it was, or what it was supposed to do.
However, a new review has me thinking about it. The paper is titled “Coenzyme Q10--A GRADE-Assessed Systematic Review and Updated Meta-Analysis of Randomized Controlled Trials.” It investigated only double-blind, randomized trials that included measures of inflammation such as C reactive protein, interleukin-6, and tumor necrosis factor. These reports included a total of 1517 subjects.
The results showed a significant reduction of all three inflammation markers among those taking CoQ10, which occurs naturally in the body, acts as an antioxidant, and plays a role in metabolic processes.
Conclusion: “This meta-analysis provides evidence for CoQ10 supplementation to reduce the level of inflammatory mediators in the general population and proposes that daily supplementation of 300–400 mg CoQ10 shows superior inhibition of inflammatory factors.” More at Molecular Nutrition & Food Research.
The “excessive exercise” guy is calming down
A decade ago, cardiologist and regular fitness runner James O’Keefe created a sensation with his pronouncements about the harms of “excessive exercise.” His TED Talk on the subject has been viewed 1.7 million times. Now, however, he appears to be softening his tone and warnings.
In a new paper, O’Keefe, his cardiologist son, and co-authors review “Training Strategies to Optimize Cardiovascular Durability and Life Expectancy.” They’ve produced a highly readable paper that performs a systematic review of journal articles from the last decade.
It attempts to answer the important, age-old question: What are the best exercises, and optimal amounts of time to spend performing those exercises, for heart health and/or life expectancy.
Several conclusions: 1--More is better for modest exercises like walking. 2--Vigorous exercise like running produces maximal benefits at 150 minutes/week, and more is not always better. More than 150 minutes/week of vigorous exercise may produce a slight increase in cardiovascular mortality, but all-cause mortality continues to drop (also slightly.) The word “excess” is used only once in the paper, and then to describe the risk of orthopedic injuries and overtraining.
The O’Keefes and coauthors also believe that HIT training can be very effective for cardio fitness, that we should strength train 40 to 60 minutes a week, that we should spend 2 hours a week in “natural settings,” and that play-type sports like tennis/badminton/soccer may confer greater benefits than cycling/swimming/running. Lastly, we should allow ample time for rest, relaxation, recovery, and sleep after strenuous exertion.
As noted above, the paper is highly readable and available in full text for free. I recommend it. More at Missouri Medicine.
In memoriam: Dick and Ricky Hoyt
The first time I saw Dick Hoyt pushing his wheelchair-bound son Ricky Hoyt in the Boston Marathon, I was, to be totally honest, shocked by the sight of them. Dick was thick and muscle-bound--no marathon whippet. The wheelchair, back then in 1980, was a heavyweight rumbler. Ricky, with his cerebral palsy, looked to be in agony.
I soon learned different, as did millions of us when we read the details about this amazing father-son love story. We are lucky to be part of a sport with so many inspiring runners. None will ever surpass Dick and Ricky Hoyt, at least not in my mind.
The father died 2 years ago, the son this week at age 61. But their story will have no finish line. More at NY Times.
SHORT STUFF you don’t want to miss
>>> Long-running mystery: What killed Pheidippides? Was it rhabdo?
>>> Plant-based eating: How to get all the protein you need
GREAT QUOTES make great training partners
“I don’t dwell on the things we can’t do. I concentrate on the things we can do.”
--Dick Hoyt
That’s all for now. Thanks for reading. See you again next week. Amby