It’s estimated that there are over 2+ million scientific papers published each year, and this firehose only seems to intensify.

Even if you narrow your focus to fitness research, it would take several lifetimes to unravel the hairball of studies on nutrition, training, supplementation, and related fields.

This is why my team and I spend thousands of hours each year dissecting and describing scientific studies in articles, podcasts, and books and using the results to formulate our 100% all-natural sports supplements and inform our coaching services. 

And while the principles of proper eating and exercising are simple and somewhat immutable, reviewing new research can reinforce or reshape how we eat, train, and live for the better. 

Thus, each week, I’m going to share five scientific studies on diet, exercise, supplementation, mindset, and lifestyle that will help you gain muscle and strength, lose fat, perform and feel better, live longer, and get and stay healthier. 

This week, you’ll learn the best way to train for endurance sports, why the ketogenic diet isn’t the best way to lose weight, and how baking soda boosts athletic performance.

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This is the best way to train for any endurance sport . . . 

Sources: “Polarized Training Is Not Optimal for Endurance Athletes” published on June 1, 2022 in Medicine & Science in Sports & Exercise.

About 20 years ago, a researcher named Stephen Seiler was on a training run in Norway when an elite runner he knew caught up with him. This wasn’t surprising, but what struck him is that this runner, who he knew from lab testing had a Vo2max of 65 (extremely high), started walking when she came to a small hill.


Why would one of the best endurance athletes alive walk up a hill? 

This question led Seiler to spend the next few years carefully analyzing the workout logs of thousands of the world’s top endurance athletes from a number of different sports including cross-country skiing, cycling, rowing, running, and triathlon, and he came to a simple conclusion

The best endurance athletes in the world spend the majority of their time training at an “easy” pace. More specifically, about 80% of their workouts are at an “easy” pace (hence the walking up hills), with the rest being a mix of moderate and high-intensity. In some sports this ratio is even more skewed, especially among cross-country skiers, rowers, and track cyclists, who often do 90-to-95% of their workouts at an easy pace.

He also found that most of the athletes in most sports did very little “moderate” training (often less than 5% of their annual workouts) and instead adopted what he called a “polarized” model: doing most of their workouts at either an easy or hard intensity, but largely skirting the middle. 

To polarize means “to divide or cause to divide into two sharply contrasting groups or sets of opinions or beliefs,” which is essentially what these athletes had done with their training intensity. 

Seiler and other researchers went on to publish a number of follow-up observational studies and randomized controlled trials proving that this training style was not only ubiquitous among top-drawer endurance athletes, but also a more effective way to train than competing methods. 

For example, many cycling races take place at what could be called a moderate-to-high-intensity, so you might assume that most of your workouts should be at the same pace, but this isn’t the case. The vast majority of their workouts are easy, with only a small percentage at “race pace.” 

Seiler’s polarized model has its critics, though, which brings us to the two papers in question. Seiler and a number of his colleagues who’ve studied polarized training published a paper arguing that the weight of the evidence supports this paradigm, whereas another team of researchers argued for the superiority of what’s referred to as pyramidal training

This is similar to polarized training in that athletes generally still do the majority of their workouts at a low intensity, followed by a much smaller fraction of moderate-intensity workouts, and then an even smaller percentage of high-intensity workouts. 

For instance, a pyramidal training program might involve 70% of workouts at an easy intensity, 20% at a moderate intensity, and 10% at a high intensity, whereas a polarized program might involve 80% of workouts at a low intensity, 5% at a moderate intensity, and 15% at a high intensity. 

Frankly, the differences in opinion between the two teams of researchers are largely semantic and academic (they’re disagreeing over the best name for what are almost the same training methodologies). For example, some studies have shown that road cyclists and triathletes do a bit more moderate intensity training than high-intensity training, but this can be explained by the way intensity is measured (heart rate tends to overestimate moderate-intensity training) and subtle differences in the demands of different endurance sports. Like I said, splitting hairs. 

Instead of spotlighting what these two camps disagree on, it’s more instructive to focus on what they do agree on.

When you connect the dots, here are the key takeaways from both studies:

  1. Basically all successful endurance athletes at the highest levels of competition do the majority of their workouts at a fairly low intensity (around 70% of heart rate or less). Many athletes call this their “all day pace,” which allows them to speak in full sentences easily. 
  2. There are a lot of physiological reasons for this, but the substance is that you can keep reaping the benefits of low-intensity workouts up to breathtakingly high volumes (as in 30 hours per week in some cases), whereas the benefits of moderate and high-intensity workouts tend to peter out at relatively low volumes (just a few workouts per week). And since high-intensity workouts are much harder on the body, you can only do so many until the wheels fall off, so the logical conclusion is to do a shite-ton of low volume training with a sprinkling of higher-intensity workouts. 
  3. Specifically, most successful endurance athletes, from Olympic gold-medalists to weekend warriors, do no more than about 1-to-2 moderate- to high-intensity workouts per week and the rest of their workouts are relatively easy, “long slow distance” sessions. The main difference between the pros and the rest of us is their “hard” workouts are soul-crushingly difficult (though most still top out at 45-to-60 minutes) and they do way more low-intensity training than most mortals can stomach. 

“But Mike!” you say, “I can’t potter around on my bike 20 hours per week. I need to make my workouts count!”

A reasonable counterargument, but research shows that the polarized model still holds true even for recreational athletes who train less than pros. The reason?

Most folks tend to adopt a relative perceived exertion that’s “somewhat hard,” or moderate intensity. Moreover, they also train at this intensity almost all of the time, rarely doing an easy or truly hard workout.

This undercuts their performance in two ways: First, they aren’t able to do as much low-intensity training (since they spend more time fatigued or injured), and second, they’re never able to really push themselves in their hard training. Unless they consciously restrain themselves during their “easy” workouts and push themselves in their “hard” workouts, they get mired in the mushy middle and stagnate. 

It takes deliberate effort—discipline—to keep a lid on your intensity in most of your workouts. Ironically, though, going a bit slower is what allows you to go a lot faster when it counts. 

(There is a limit to this logic—if you only train 30 minutes per week, then it should probably be at a high intensity—but then you’d have to ask yourself if you’re really “training” for an endurance sport or just staying active).

Whether you call this polarized, pyramidal, bifurcated, Paretoesque, or something else, it’s the best way to train for endurance sports. 

TL;DR: If you want to become a better endurance athlete, do about 80% of your workouts at an “easy” intensity, and the rest of your workouts at a moderate-to-hard intensity. 

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The ketogenic isn’t better than a moderate-carb diet for losing weight.

Source: “Ketogenic low-carbohydrate diets have no metabolic advantage over nonketogenic low-carbohydrate diets” published in May 2006 in The American Journal of Clinical Nutrition.

The ketogenic diet is unique among fad diets for a few reasons.

First, unlike arrant quackery like the Blood-Type Diet, Bone Broth Diet, and Military Diet, there are some legitimate applications of the ketogenic diet (it was originally created to help treat epilepsy, for example).

Second, it’s actually been the subject of high-quality research for over a decade, whereas most fad diets have approximately zero research for or against them. 

Some of the earliest studies on ketogenic diets and weight loss found that people who cut out almost all carbs lost more weight than people following moderate-carb diets, but there were two problems with these studies: The keto group generally ate more protein (which helps reduce appetite and boost fat loss), and some of the studies only measured total weight loss, but not fat loss. 

Since ketogenic dieting can cause large amounts of water loss (every gram of carbohydrate is stored with about 3-to-4 grams of water), it wasn’t possible to distinguish between fat or fluid losses in these studies. 

What if you compared a moderate carb diet and a ketogenic diet with the same amount of protein, and carefully measured fat loss and not just weight loss? 

That’s the question a team of scientists at Arizona State University set out to answer in one of the most carefully controlled studies on the ketogenic diet ever performed.

The researchers divided 20 overweight men and women into 2 groups: A keto diet group who ate ~30 grams of carbs per day and a moderate-carb group who ate ~160 grams of carbs per day. Both groups also ate 1,500 calories per day and the same amount of protein (~0.5 grams of protein per pound of body weight).

The scientists prepared every meal the participants ate during the 6-week study so that they knew exactly how many calories and grams of protein they consumed. 

The results showed that the group following the keto diet lost almost exactly the same amount of fat, muscle, and overall weight as the group following the moderate-carb diet (though the moderate-carb group lost a touch more fat and weight).

The ketogenic diet group also reported feeling poorly by the end of the study and having less energy and motivation to move around. Not only would this make it more difficult to stick to the diet, it would also reduce the number of calories you burn through exercise and hamper your ability to lift heavy weights, which makes it harder to lose fat and maintain or gain muscle. (Several other studies have also found that following high-fat, low-carb diets makes people feel lethargic, reduces their energy expenditure, and hurts their athletic performance.)

Finally, the moderate-carb diet proved to be significantly more nutritious than the ketogenic one. Neither group ate the recommended daily intake (RDI) for vitamin E, magnesium, or iron, but the moderate-carb group got closer. The keto group also fell short of the RDI for thiamin, folate, calcium, and fiber, whereas the moderate-carb group got plenty of those nutrients. That’s not a big deal if you’re only following a diet for a few months to lose weight, but it could lead to significant micronutrient deficiencies over time.

In the end, so long as you eat the right amount of protein and number of calories, how much carbs or fat you eat is far, far less important. 

While I think most people fare better with a moderate-to-high-carb approach, especially if they lift weights, I’ve also seen people build impressive physiques following nearly zero-carb ketogenic diets and extremely low-fat, high-carb plant-based diets.  

The common denominator is that they always ate sufficient protein and the right number of calories for their goals (bulking or cutting). And, of course, lifted weights.

If reading this has got you wondering what kind of diet is right for your circumstances and goals, then take the Legion Diet Quiz! In less than a minute, you’ll know exactly what diet is right for you. Click here to check it out.

TL;DR: You’ll lose the same amount of weight and fat on a ketogenic diet as you will on a moderate or high-carb diet as long as you eat the same amount of protein and calories. There’s nothing special about keto for weight loss. 

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Baking soda boosts your athletic performance.

Source: “International Society of Sports Nutrition position stand: sodium bicarbonate and exercise performance” published on September 9, 2021 in Journal of the International Society of Sports Nutrition.

Scientists are still unraveling exactly what causes fatigue during exercise, but one of the things they’re fairly certain of is that it’s related to a buildup of acidic compounds inside your muscles. 

One potential way to improve athletic performance, then, would be to improve the body’s ability to resist the buildup of these acids and clear them faster once they start to accumulate.

And according to this study, gulping down some baking soda (sodium bicarbonate, aka bicarb) may be one of the easiest ways to do this. 

As you probably remember from middle school, baking soda is a base (it has a pH above 7) whereas acids are, well, acidic (they have a pH below 7). Researchers have been testing baking soda’s ability to counteract the buildup of acid in muscles and reduce fatigue for years, and this study reviewed every previous trial they could find to get a bird’s eye view of the evidence. 

Here’s what they found after analyzing the results of 146 studies on baking soda and physical performance:

1. Supplementing with 0.2-to-0.5 grams (16-to-41 grams for a ~180 pound man) of baking soda per kilo of body weight improves muscular endurance during high-intensity exercise lasting between 30 seconds and 12 minutes.

2. Supplementing with baking soda improves performance in single- and multiple-bout exercise (one sprint versus five sprints, for example) in both men and women.

3. You can get the benefits of baking soda by taking it shortly before training (single dose) or for several days leading up to an important workout or competition (multiple dose). 

If you take it as a single dose, the optimal dose is 0.3 grams of baking soda per kilo of body weight taken 1-to-3 hours before exercise. Taking more than this won’t improve performance further and increases the risk of experiencing bloating, nausea, and stomach cramping.

If you take it in multiple doses, the optimal dose is 0.4 or 0.5 grams of baking soda per kilo of body weight per day for 3-to-7 days leading up to a key workout or competition. (You can take it on the day of competition as well, but it’s best not to if it upsets your stomach.)

With this approach, it’s best to take baking soda in small doses throughout the day instead of one large dose (0.1-to-0.2 grams of baking soda per kilo of body weight at lunch and dinner, for example). The main benefit of multidosing like this is it reduces the risk of bloating and stomach cramps.

4. Supplementing with baking soda before every training session for a prolonged period (at least 6-to-8 weeks) may boost performance more than taking it less regularly, but there isn’t as much research on long-term supplementation.

5. The most common side effects of baking soda supplementation are bloating, nausea, vomiting, and abdominal pain, though these are rare.

These digestive issues are generally caused by consuming a large amount of baking soda at once, and the best way to avoid them is to consume it in smaller doses throughout the day, ideally with food, and about three hours before your workout. Taking it in capsule form may also help as well.

6. Taking baking soda with creatine or beta-alanine may enhance physical performance more than taking each in isolation.

7. It’s possible that some of baking soda’s benefits are due to the placebo effect. While you could say this about any supplement, it’s hard to blind people to baking soda consumption (due to the taste, texture, and occasional digestive symptoms), so people often know they’ve taken it. A recent review found that the placebo effect may account for up to 30% of baking soda’s benefits.

One of the reasons I’m optimistic about baking soda’s performance-enhancing abilities is that it’s proven to work in a variety of different sports, including rugby, tennis, basketball, and soccer; martial arts such as boxing, judo, wrestling, and jiu-jitsu; endurance sports like cycling, running, swimming, and rowing; and most importantly, weightlifting. 

When it comes to weightlifting in particular, baking soda consistently increases the number of reps people can perform per set (it improves muscular endurance). For instance, one study found that weightlifters could do significantly more reps to failure on squats after taking baking soda, and these benefits became more pronounced as the workout dragged on (12 reps vs. 12 reps in set 1, 11 reps vs. 7 reps in set 2, and 9 reps vs. 6 reps in set 3).

You may be wondering, if baking soda is such a banger, then why isn’t it more popular? 

A few reasons: 

  1. You have to consume a fairly large amount, which means swallowing a lot of pills or powder.
  2. Some people experience stomach upset when they take it in large amounts (although you can mostly eliminate this with the above tips). 
  3. It’s cheap and can be purchased at your local grocery store, so there’s little incentive for supplement companies to market it.

That said, if you want to maximize your athletic performance, especially in any kind of exercise lasting from about 30 seconds to ~12 minutes, it’s worth giving baking soda a try. 

If you’d like to maximize its benefits (and mask the taste and texture), try combining it with a 100% natural, safe, and science-backed pre-workout such as Pulse

As you saw above, some research shows that combining baking soda with beta-alanine, which is found in Pulse, may produce even better results than taking either in isolation. If you give this a try, I recommend splitting your daily baking soda dose into two or three mini doses, and taking one or two with Pulse and one or two at another point in the day (taking a full dose of baking soda with Pulse isn’t very palatable).

Or if you aren’t sure if Pulse is right for you or if another supplement might be a better fit for your budget, circumstances, and goals, then take the Legion Supplement Finder Quiz! In less than a minute, it’ll tell you exactly what supplements are right for you. Click here to check it out.

TL;DR: Taking 0.2-to-0.5 grams of baking soda per kilo of body weight reliably improves athletic performance during exercise that lasts about 30 seconds to 12 minutes.

+ Scientific References