Research Roundup #1: Bench Press Grip, Keto Diets for Weight Loss, Collagen Protein Supplements, and More

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 help us understand why the fundamentals work, how to better implement them, and occasionally, uncover new and better methods to achieve our fitness goals.

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 about the proper bench press grip for building muscle, whether or not keto is better than normal dieting for weight loss, how pre-performance rituals enhance athleticism, and more.

Table of Contents

• Bench press grip width doesn’t change which muscles you train.
• The keto diet is no better than regular dieting for weight loss (and may be worse for muscle and strength gain).
• Collagen protein isn’t better for building muscle than whey protein (even when it’s spiked with leucine).
• Rhodiola rosea boosts anaerobic performance as much as caffeine.
• Pre-performance routines help you perform at your best.

Bench press grip width doesn’t change which muscles you train.

Source: “The Effect of Grip Width on Muscle Strength and Electromyographic Activity in Bench Press among Novice- and Resistance-Trained Men” published on June 14, 2021 in the International Journal of Environmental Research and Public Health.

It’s a longstanding piety among weightlifters that bench pressing with a wide grip primarily trains your pecs, and pressing with a narrow grip trains your triceps.

This study, conducted by scientists at Western Norway University of Applied Sciences, casts doubt on this dogma. The scientists split 28 men into two groups: A “resistance-trained” group and a “novice-trained” group. The resistance-trained participants had at least one year of weightlifting experience and were able to bench press at least 125% of their body weight, and the novice-trained participants had performed no training for at least six months but were familiar with the bench press.

The researchers then had all participants perform three sets of six reps of bench press with either a wide, regular, or narrow grip while attached to an EMG, which measured the activation of their pecs, triceps, and deltoids.

They found that grip width had almost no impact on muscle activation—all of their muscles were activated about the same amount regardless of their grip width, with two exceptions: 

1. Among weightlifters with at least 1 year of training experience, triceps activation was significantly greater with the medium grip than the wide grip.
2. Among weightlifters with no recent training experience, front delt activity was significantly greater with the medium grip than the narrow grip.

That said, although these differences were statistically significant, they weren’t large enough to make a meaningful impact on muscle growth. 

While some other studies have shown that using a narrower grip tends to cause a larger increase in triceps activation, this study and others like it indicate that using a wider-than-normal grip width probably doesn’t significantly improve chest muscle activation. 

(If you like training tips like this and want an even more in-depth guide to how you should train to build your best body ever, check out my fitness books for men and women, Bigger Leaner Stronger and Thinner Leaner Stronger.)

The Takeaway: Although bench pressing with a slightly narrower grip emphasizes your triceps, bench pressing with an extra-wide grip probably isn’t better for training your pecs than a medium-width grip.  

The keto diet is no better than regular dieting for weight loss (and may be worse for muscle and strength gain).

Source: “The Influence of Cyclical Ketogenic Reduction Diet vs. Nutritionally Balanced Reduction Diet on Body Composition, Strength, and Endurance Performance in Healthy Young Males: A Randomized Controlled Trial” published on September 3, 2020 in Nutrients. 

Despite its popularity, there’s no consensus on whether the ketogenic diet has any benefit over conventional diet strategies for improving body composition or performance. 

This study, conducted by scientists at the First Faculty of Medicine and General University Hospital, adds to a growing body of evidence showing keto is mostly sizzle with little steak.

In this study, researchers split 25 young men into two groups: A group that followed a ketogenic diet and a group that followed a balanced diet. Both groups maintained a calorie deficit of 500 calories per day and followed a 3-day push pull legs training program for 8 weeks.

At the end of the study, the results showed that the keto group lost some fat and muscle, gained no strength, and didn’t improve their endurance. Conversely, the balanced diet group lost about twice as much fat as the keto group, maintained their muscle, and increased their strength and endurance. 

It’s important to remember that this is just one study, which means it’s not enough to entirely write off the keto diet (the strongest argument in favor of keto is that some people find it helps reduce their appetite). Nonetheless, it’s more proof that keto isn’t the “One True Diet” many advocates claim.

(And 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 best for you. Click here to check it out.)

The Takeaway: Following a moderate- to high-carb diet while cutting will probably help you lose more fat, maintain more muscle, and perform better than following a keto diet.

Collagen protein isn’t better for building muscle than whey protein (even when it’s spiked with leucine).

Source: “Whey Protein Supplementation Is Superior to Leucine-Matched Collagen Peptides to Increase Muscle Thickness During a 10-Week Resistance Training Program in Untrained Young Adults” published on January 17, 2022 in the International Journal of Sport Nutrition and Exercise Metabolism.

Collagen protein powder is more popular now than ever, mainly because of its low cost. What many consumers don’t realize, though, is that the reason it’s so cheap is that it’s abysmally low in the amino acids most responsible for muscle growth. 

To get around this, supplement companies often “spike” their collagen with the amino acid leucine. Doing so, they say, makes collagen as good at supporting muscle growth as whey—a theory this study sought to test.

The researchers split eight men and three women into two groups: a whey protein group and a leucine-spiked collagen protein group.

Both groups completed a 10-week strength training program and consumed ~1.6-to-2 grams of protein per kilogram of body weight per day, with 35 grams of that daily protein coming from either whey or collagen. After “fortification,” each supplement contained a total of 3 grams of leucine, too.

The results showed the whey protein group gained significantly more muscle than the collagen protein group. Specifically, the whey protein group increased vastus lateralis (a quad muscle) size by 8.4% and biceps size by 10.1%, whereas the collagen group only increased vastus lateralis size by 5.6% and biceps size by 6%.

This shows that it’s not just a lack of leucine that makes collagen a poor protein supplement—its entire amino acid profile is wanting. The most likely reason for this is that although leucine kickstarts the muscle-building process, you still need other amino acids to actually create new muscle proteins. Thus, if your goal is to gain muscle, don’t waste your money on collagen protein.

In other words, spiking collagen protein with leucine is like “enriching” dirt by adding the gold dust back into it. Collagen protein is an extremely low-quality byproduct of food production, and sprinkling a little leucine on top doesn’t make it as good as the real McCoy.

(And if you’d like even more specific advice about which supplements you should take to reach your health and fitness goals, take the Legion Supplement Finder Quiz.)

The Takeaway: Collagen is less effective than whey at supporting muscle growth, even when you artificially increase the amount of leucine in collagen to match whey.

Rhodiola rosea boosts anaerobic performance as much as caffeine.

Source: “Effects of short-term Rhodiola Rosea (Golden Root Extract) supplementation on anaerobic exercise performance” published on October 29, 2018 in the Journal of Sports Sciences.

Rhodiola rosea (also known as Golden Root) is a plant that grows in the Arctic regions of Europe, Asia, and North America. Several studies show that it effectively reduces perceptions of mental and physical fatigue and improves cognitive performance when you feel tired or stressed, leading many people to speculate that it might boost physical performance, too.

To test this hunch, scientists at Samford University had 11 women take either 500 mg of rhodiola or a placebo 3 times per day for 3 days then report to the lab for testing. When the participants arrived at the lab, they were given another 500 mg dose of either rhodiola or the placebo 30 minutes before performing a Wingate test, which consists of three 15-second all-out cycle sprints separated by 2 minutes of rest. While the participants completed the test, the researchers evaluated several measures of anaerobic performance.

The results showed that taking rhodiola improved Wingate performance by ~4-to-8.5%. To put that into perspective, a recent study showed that caffeine supplementation only improves Wingate performance by ~3-to-4%.

In other words, rhodiola improved anaerobic performance about as much as caffeine, at least in this study.

(And if you’d like to see if you can get similar results and want a 100% natural rhodiola rosea supplement that also contains clinically effective doses of three other ingredients designed to balance hormones, increases energy levels, and reduces stress and fatigue, try Vitality.)

The Takeaway: In this study, supplementing with rhodiola rosea improved anaerobic performance by ~4-to-8.5%, making it at least as effective as caffeine.

Pre-performance routines help you perform at your best.

Source: “The effectiveness of pre-performance routines in sports: a meta-analysis” published on October 14, 2021 in the International Review of Sport and Exercise Psychology.

Most athletes—professional and amateur—go through a “pre-performance routine” (PPR) before performing their given sport. For example, before taking a free throw, Michael Jordan would take a shoulder-width stance, spin the ball in his hands, bounce it three times, fixate on the rim, and then spin the ball again before shooting.

And although many people believe these sporting ticks are nothing more than superstitious habits, research conducted by scientists at the University of Vienna shows they give us a performance boost.

In their meta-analysis, the researchers parsed the results of 33 papers and found that regardless of the stakes, the experience of the athlete, or the particulars of the ritual, performing a pre-performance routine improves athletics performance. 

It’s worth noting that none of the studies included in the meta-analysis looked at weightlifting. Still, it’s reasonable to assume that PPRs would do the same for a weightlifter about to pull a deadlift one-rep max as they would for a golfer approaching a tee. Anecdotally, most high-level powerlifters, Olympic weightlifters, and other strength athletes also use some kind of pre-lift procedure.

So, whether you use active imagery, mentally recite weightlifting cues, or simply listen to a weightlifting playlist while you set up for a heavy lift, PPRs will likely help you perform slightly better.

The Takeaway: Running through a “pre-performance” routine such as taking a few deep breaths or rehearsing what you’re about to do in your mind’s eye boosts athletic performance.