Tyler Robbins Fitness

B.Sc. Biochemistry, Certified Strength and Conditioning Specialist (CSCS), Certified CrossFit Trainer (CCFT/CF-L3), USA Weightlifting Level 1

Filtering by Category: "Nutrient Timing"

Day 115 - Nutrient Timing for Resistance Exercise Part 3



Part 1 the other day covered nutrient timing prior to exercise, and how it effects performance.

Part 2 dealt with post-exercise nutrition and how it effects recovery.

For those of you who may have missed part 1 or part 2, I came across an absolutely amazing article in the Strength and Conditioning Journal titled, "Nutrient Timing for Resistance Exercise" written by a team of PhD and CSCS certified individuals. This is probably the single-greatest resource I have come across detailing what is referred to as "nutritional timing" when it comes to resistance training, so if you are interested, pick up a copy for yourself!

Part 3: Net Protein Balance

Think of your body as a construction site, with tissues constantly being broken down and either repaired or replaced. This is known as having a 'negative' net protein balance.

Having a negative net protein balance, or in other words, a catabolic state, is stimulated from resistance training, but also occurs when the body is at rest. Tissues are being broken down due to misuse, or in the case of resistance training - use, at all times.

The focus of individuals who wish to positively grow their muscles, or induce an anabolic state, should be of great interest, especially when resistance training.

The diet is therefore of great interest for those who resistance train, as the goal of improving one's muscles to improve size and/or strength plays a key role.

When discussing post-exercise nutrition, it should be noted that carbohydrates are important to not only return the body to pre-exercise levels of glycogen (energy stores), but have also been shown to reduce muscle protein breakdown.

Having said that, individuals should consume sources of amino acids/protein following exercise in order to feed the body the proper building blocks to reduce muscle protein degradation, but to also stimulate muscular growth.

What types of protein are best? The article says:

Whole-protein sources (including whey, casein, and soy protein sources), when ingested either before or after an acute bout of resistance exercise, also significantly improve net protein balance by increasing rates of protein synthesis. In one of these investigations, it was reported that whey protein was superior to soy and casein in its ability to incrase protein synthesis (approximately 22g of each type of protein was ingested after resistance exercise). Surprisingly, even though soy is lower in quality than casein, they found that of the 3 protein sources, casein resulted in the lowest net response in protein synthesis. The authors suggested that this was a factor of the slow rate of digestion induced by casein. Therefore, after resistance exercise, it may be ideal to select a protein source high in BCAA content (whey) that is also fast digesting in nature.

Okay, so following exercise, it is best to consume either a beverage or meal containing some protein. So how much is ideal? I have seen many personal thoughts tossed around from individuals over the years, who claim to know the 'perfect amount' of protein. This article has an opinion of its own:

Research conducted at McMaster University sough to answer this question by giving male subjects (with at least 4 months of resistance training experience) 5 different amounts of protein in a randomized crossover design. Immediately after a lower-body resistance exercise bout, the subjects consumed drinks containing 0, 5, 10, 20, or 40g of whole egg protein. After consuming the whole egg protein supplement, protein synthesis was measured for the next 4 hours. Mean mixed muscle protein synthesis was maximally stimulated with 20g of whole egg protein (meaning that ingesting 40g of protein offered no additional benefit than 20g of protein in terms or maximizing protein synthesis rates). In terms of relative dosage, this amount of protein was equivalent to 0.23g of whole egg protein per kilogram of body mass.

Although a snack or meal containing amino acids/protein is highly recommended following resistance exercise, it should be noted that research shows that a mixture of protein and carbohydrates is the optimal scenario for post resistance-workout nutrition as the carbohydrates aid in reducing protein catabolism, replenish spent glycogen stores, not to mention the protein aids in tissue anabolism.

Quote of the day:
"To climb steep hills requires a slow pace at first."
~ William Shakespeare






Day 114 - Nutrient Timing for Resistance Exercise Part 2


Part 1 the other day covered nutrient timing prior to exercise, and how it effects performance. Today will cover nutrient timing following exercise.

For those of you who may have missed part 1, I came across an absolutely amazing article in the Strength and Conditioning Journal titled, "Nutrient Timing for Resistance Exercise" written by a team of PhD and CSCS certified individuals. This is probably the single-greatest resource I have come across detailing what is referred to as "nutritional timing" when it comes to resistance training, so if you are interested, pick up a copy for yourself!

Part 2: Recovery After a Resistance Exercise Bout

Carbohydrate and Muscle Glycogen Resynthesis

It is no surprise that muscle glycogen levels become depleted from a resistance training session. The level of depletion is entirely dependent on the work being completed, however. In any respect, an athlete who trains multiple times a day, or even multiple days in a row, should be interested in post-workout nutrition.

In order to maintain performance, an individual should approach post-exercise nutrition as a chance to re-fuel their muscles to prepare for the following workout. Keep in mind that for muscle glycogen replenishment, the goal is to maintain a high level of performance. A discussion on protein synthesis can come later.

To return muscle glycogen levels to 90% of pre-exercise values, the article explains:

Given that 1 g/kg/h was as effective as 1.5 g/kg/h, it can be concluded that 1 g/kg/h is sufficient for resynthesizing skeletal muscle glycogen after resistance exercise to levels reaching 90% of pre-exercise values. After this dosing schedule, a 180-pound individual would ingest about 82g of carbohydrate immediately after and then again 1 hour after their resistance exercise workout (totalling ~165g of carbohydrates within an hour after completing the resistance exercise workout).

Carbohydrate Plus Protein and Muscle Glycogen Resynthesis

This category takes things a step further as the subject of protein synthesis is added to the goal of restoring muscle glycogen levels.

The authors discuss findings from studies looking at various types of post-workout beverages including carbohydrates only, carbohydrate/protein/fat mixes, as well as placebo beverages (calorie-free).

To be honest, I have heard many individuals discuss the idea that dietary fats should be avoided in post-workout recovery beverages/meals, as the fats can slow digestion. This appears to me to be common thought/practice amongst many in the fitness industry, however, the authors of this article present findings that refute that belief.

Another interesting aspect of this study is the inclusion of fat calories in the post-exercise beverage. It has often been suggested that adding fat to the post-workout recovery beverage should be avoided because of its potential to slow down the digestion and absorption of ingested carbohydrate (which may suppress the rate of skeletal muscle glycogen resynthesis). The finding of this study indicates that adding fat to the post-workout carbohydrate-protein beverage does not negatively alter the rate of skeletal muscle glycogen resynthesis. In further support of this position, when subjects were given a post-endurance workout beverage containing carbohydrate, protein, and fat (even up to 45% of the calories being derived from fat), it was reported that the added fat content did not alter muscle glycogen resynthesis or glucose tolerance the next day.

Protein/Amino Acids and Muscle Damage

Part of the reason or need for a post-exercise recovery beverage is to suppress muscle damage and decrease DOMS (delayed-onset muscle soreness). Resistance exercise causes micro trauma to muscle fibers in order for the body to repair the damage, returning the muscle to a stronger state.

It really should be no surprise that supplementing resistance exercise with protein/amino acids should be encouraged to elicit muscle repair.

Recovery from a bout of resistance exercise includes replenishing skeletal muscle glycogen, reducing muscle soreness, and attenuating serum markers of muscle damage. Ingesting a carbohydrate-protein beverage after resistance exercise will replenish skeletal muscle glycogen. Also, BCAA supplementation taken in conjunction with resistance exercise has been shown to enhance recovery by suppressing both muscle soreness and damage.

Protein or amino-acid supplementation is often thought of as only being useful to those who resistance train. It should be noted, however, that endurance athletes could also benefit from a sufficient dosing of protein in their diet to maintain current levels of muscle tissue and reduce the catabolic effect chronic cardio plays on their bodies.

Quote of the day:
"I am an optimist. It does not seem too much use being anything else."
~ Winston Churchill




Day 111 - Nutrient Timing for Resistance Exercise Part 1


I came across an absolutely amazing article in the Strength and Conditioning Journal titled, "Nutrient Timing for Resistance Exercise" written by a team of PhD and CSCS certified individuals. This is probably the single-greatest resource I have come across detailing what is referred to as "nutritional timing" when it comes to resistance training, so if you are interested, pick up a copy for yourself!

I am not going to copy the entire article obviously, but over the next few blogs, I am going to include a few snippets and details from the article here on my blog to not only inform all of you, but to also try and convince you to pick up a copy of the article for yourself (if possible).

Part 1: Enhancing Performance in Individual Resistance Exercise Training Bouts

Carbohydrate

During resistance training, our muscles use and expend muscle glycogen. That is the primary fuel source for strength training. I have personally seen many debates regarding whether or not to supplement prior to a resistance training session with carbohydrates to enhance performance. Here is what the article has to say:

Despite this depletion of skeletal muscle glycogen, the majority of studies in which supplemental carbohydrate was ingested before a resistance training bout did not report improvements in resistance training performance. In the limited studies that reported a performance-enhancing effect of pre-exercise carbohydrate supplementation, it should be noted that the resistance training workouts were not of a practical nature and did not resemble workouts that are conducted in a typical athletic strength and conditioning program.

It should be noted that certain individuals feel the need to consume something prior to a resistance workout in order to avoid "bonking". For most individuals (such as myself), training on an empty stomach (early morning for example) should not be a problem as your muscles and liver store plenty of glycogen to sustain energy levels for a resistance training session.

On the other hand, if you believe that you "hit a wall" towards the end of your workout, you may want to either try consuming a small amount of carbs prior to a workout, or consume proper amounts of nutrition following a workout. It is the post-workout nutrition that allows you to sustain energy levels for following bouts of exercise.

Protein/Amino Acids

This is also a common debate amongst fitness enthusiasts. Many believe that supplementation of branch-chain amino acids (BCAAs) prior to exercise will enhance performance during a training session. Turns out, however, that only 3 of the approximately 20 amino acids are oxidized for energy (leucine, isoleucine, and valine), and going beyond that, they are oxidized for energy at levels below carbohydrates and fats.

The authors reported that the BCAAs had no effect on resistance exercise performance. Because of their limited role in oxidation during exercise and their inability to improve acute resistance exercise performance, amino acids should not be ingested before a resistance exercise bout, with the belief that they will improve the performance of the subsequent workout.

Keep in mind that the authors of this article clearly state that pre-workout consumption of BCAAs should not be used with the belief that they will improve performance, however there may be some validity to ingesting protein prior to a training session to reduce/reverse the catabolic effect.

Carbohydrate and Protein Supplementation

Similar to ingesting either carbohydrates alone, or protein alone prior to a workout, a concoction including carbohydrates and protein together yield no measurable benefits on performance.

In summary, it appears that ingesting carbohydrate alone, protein/amino acids alone, or carbohydrate plus protein before resistance exercise does not improve the performance of the resistance exercise workout in terms of total amount of weight lifted during the workout. In contrast, there are favorable outcomes resulting from carbohydrate and protein supplementation in terms of enhancing adaptations over time and on recovery.

Today's blog covered a good portion of pre-workout nutritional timing, Sunday's blog will then be targeting post-workout nutritional timing.

Quote of the day:
"Defeat is not the worst of failures. Not to have tried is the true failure."
~ George Edward Woodberry