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 three 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 whether advanced weightlifters can “recomp,” how to predict strength gain, and if beetroot juice boosts weightlifting performance.

Experienced weightlifters may be able to “recomp.”

Source: “Body Recomposition: Can Trained Individuals Build Muscle and Lose Fat at the Same Time?” published in October 2020 in Strength and Conditioning Journal.

If you’ve been training for more than a year or two, you’ve probably heard that your days of being able to build muscle and lose fat simultaneously (“recomp”) are kaput.

This is because you become less responsive to the effects of weightlifting as you gain experience (especially after you’ve been training for 3+ years) and can no longer build muscle while “cutting”—dieting to lose fat and maintain your muscle mass. Most experts agree that at this stage, the best way to expedite muscle gain is to “bulk”—diet to build muscle while gaining a small amount of body fat.

A review conducted by scientists at the University of Tampa challenges this doctrine, claiming that recomping is possible in advanced weightlifters under certain circumstances.

They argue that the idea that you can’t gain muscle while cutting comes largely from research on bodybuilders, who, unlike most recreational weightlifters, take dieting to the extreme, only stopping once their body fat percentage is exceptionally low. During these diets, their bodies are severely stressed, and their sleep, hormones, and metabolism are so hog-tied that building muscle is nearly impossible.

When you look at less compromised weightlifters, however, there’s evidence that recomping is achievable, even for experienced trainees. This is especially true in studies that have weightlifters eat large amounts of protein.

The authors also explored how sleep, stress, hormones, and metabolic rate affect your ability to recomp. 

They found that people who reduce their sleep by just an hour per night are more likely to lose muscle, retain fat, and experience hormonal shifts that increase hunger, which makes recomping trickier. Losing sleep may also mar your performance in the gym and slow your subsequent recovery, hindering your ability to build muscle.

Furthermore, not sleeping enough can increase cortisol, glucose, and insulin levels and decrease testosterone, adiponectin, and growth hormone levels, which also make it harder to recomp.

In other words, if you don’t get enough sleep every night (7-to-9 hours for most people), you don’t have a cat in hell’s chance of recomping as an advanced weightlifter.

With these considerations in mind, here’s what the researchers recommend to give yourself the best chance of recomping as a seasoned trainee:

  1. Do at least 3 strength training workouts per week that focus on progressive overload.
  2. Consume 1.2-to-1.6 grams of protein per pound of fat-free mass (your total body weight minus the weight of your body that’s fat, which you can calculate here) per day. This will work out to about 1 of protein per pound of body weight per day for most folks.
  3. Use whey or casein protein powder to increase your daily protein intake (and if you want a clean, convenient, and delicious source of protein, try Whey+ or Casein+).
  4. Prioritize sleep. (7-to-9 hours per night is a good target).

The researchers didn’t recommend how many calories you should eat to recomp. This is most likely because the studies that found evidence of recomping in advanced weightlifters used different diets, making it difficult to pinpoint which protocol is best.

That said, a sensible starting point is to eat ~10-to-15% more calories than you burn each day, with all of the extra calories coming from protein. 

TL;DR: Advanced weightlifters may be able to recomp if they follow a high-protein diet, eat slightly more calories than they burn per day, and get 7-to-9 hours of sleep per night.

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Here’s how to predict strength gain over time.

Source: “Long-Term Time-Course of Strength Adaptation to Minimal Dose Resistance Training Through Retrospective Longitudinal Growth Modeling” published on May 19, 2022 in Research Quarterly for Exercise and Sport.

Setting challenging but achievable strength goals is one of the best ways to stay motivated to train long term. 

Conversely, setting unrealistic goals leads to frustration and failure, and can suck the fun out of working out.

How do you know what’s achievable and what’s not, though?

This study conducted by scientists at Solent University gives us a rule of thumb to predict future strength gain, making it easier to understand what you can achieve over a given timescale and what might be asking too much.

The researchers used the data from a gym chain that invites its clients to train once per week under the supervision of a personal trainer. In each workout, the clients perform 1 set of 6 machine exercises to failure, and increase the weights when they can perform at least 6 reps in a set. 

(While this isn’t a typical way to train, the data is still valuable because it gives us information about  ~15,000 people who all followed the same training program, many for longer than a year.)

To make their data even stronger, the researchers also got statistics from 10,000 competitive weightlifters on the OpenPowerlifting website and gathered information from ~1,000 weightlifters on the /r/weightroom subreddit.

This means they had data on people who lift weights to stay healthy (the gym clients), people who take weightlifting semi-seriously but don’t compete (the reddit users), and people who take lifting very seriously (the competitive powerlifters).

The results showed that strength gain in all three groups followed a “linear-log” relationship. That is, if it took a year to increase your one-rep max on an exercise by 100 lb, it would take 2 years to increase it by another 100lb, 4 years to increase it by a further 100 lb, 8 years to make the next 100-lb jump, and so on. 

Another way to think of these results is that you can gain about half as much strength over the next 12 months as you gained over the previous 12 months—if you added 50 pounds to your bench press last year, you can expect to gain 25 pounds this year, and so on. (This closely mirrors the rate at which most people can gain muscle, which further reinforces the close tie between muscle and strength gains.) 

The sole proviso is that you should only expect this rate of progress when your training, nutrition, and recovery are optimized and consistent. In other words, don’t expect to make predictable progress if one month you’re training hard, eating right, and sleeping well, and the next month you’re skipping workouts, ditching your diet, and up every night until the early hours.

This paper also provides further proof that men and women gain strength at a comparable rate (relatively speaking). This is something I’ve long been aware of, both because of the results men and women make on my programs Bigger Leaner Stronger and Thinner Leaner Stronger, and because research shows it to be true.

As you set your training goals for the coming months or years, keep in mind that if it took you 6 months to add 50 lb to your bench press, it’ll probably take you another year to add your next 50 lb, and another 2 years after that to add 50 lb more. This should keep your goals ambitious but attainable, which will help to keep you engaged with your training.

Remember too that there is an eventual limit to how much strength you can gain, just as there’s a ceiling for how much muscle you can gain (naturally). While not reflected in this study (which only covered a few year’s worth of weightlifting), there is a point where further strength gains become nearly impossible. 

(And if you’re not currently following an optimized strength training program and feel you aren’t progressing as fast as you should, take the Legion Strength Training Quiz, and in less than a minute, you’ll know the perfect strength training program for you. Click here to check it out.)

TL;DR: Strength gain follows a “linear-log” relationship. This means that if it takes 1 year to add 100 lb to your squat, it’ll probably take 2 years to add the next 100 lb, 4 years to add another 100 lb, 8 years to add a further 100 lb, and so on (until you reach your genetic limit for strength and muscle gain). 

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Beetroot juice boosts power and muscle endurance.

Source “Effect of Acute Beetroot Juice Supplementation on Bench Press Power, Velocity, and Repetition Volume” published in April 2020 in The Journal of Strength and Conditioning Research.

For almost 20 years, “nitric oxide boosters” such as L-arginine and L-citrulline have been a mainstay of pre-workout supplements, lauded for their ability to widen your blood vessels and improve blood flow, boost exercise performance, and potentially increase muscle protein synthesis rates.

Since then, supplement manufacturers have been on the qui vive for compounds that do a similar job.

One substance they’ve kicked around as a possible candidate is beetroot juice. Some research shows it can boost performance in endurance athletes, but it’s not clear if it’s equally beneficial for weightlifters. 

Researchers at Samford University took a stab at addressing this question by having 11 experienced male weightlifters perform 2 bench press workouts 3 days apart. Two hours before each workout, the weightlifters either drank 70 ml of beetroot juice (containing ~400 mg of nitrate, a chemical that turns into nitric oxide in the body) or a placebo.

During the workout, the weightlifters did 2 sets of 2 reps as explosively as possible with 70% of their one-rep max, resting 3 minutes between sets. They then completed 3 sets to failure using the same weight, resting 2 minutes between sets.

The results showed that the weightlifters could generate more power and do more reps across the 3 sets to failure (~31 reps vs. 28 reps) after drinking beetroot juice than after the placebo.

These results are in line with other studies showing that beetroot juice can help you lift more explosively and increase the number of reps you can do before fatiguing.

What sets this study apart, though, is that the participants used a regular barbell and performed a fairly typical bench press workout, whereas many studies used obscure weightlifting machines that few people will ever actually train with.

It seems there is something to beetroot juice, but there’s still little information available on the best way to supplement with it.

The optimal dose of nitrate seems to be between 6 and 13 mmol, but it’s not clear how much beetroot juice you should drink to hit these numbers. The best time to drink beetroot juice is also an open question. Some studies have had athletes drink it several hours before training, but most research shows drinking it for several days leading up to an important workout is superior.

It’s also not clear if the improved performance thanks to beetroot juice translates into actual muscle and strength gain, although this seems like a safe assumption if it helps you have more productive workouts. 

Nevertheless, the preliminary evidence is promising, which means it might not be too long before you’re chugging beetroot juice as part of your pre-workout supplement regimen alongside other proven compounds such as caffeine, L-citrulline, and beta-alanine.

(And if you aren’t sure if beet juice is right for you or if another supplement might be a better fit for your budget, circumstances, and goals, 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: Drinking beetroot juice 2 hours before weightlifting may boost power and muscle endurance.

+ Scientific References