The ultimate guide to training nutrition Nutrients and timing Part 2

Having looked at the physiological processes that take place in response to training and food intake in the first part, in this second part of this article I will look at the individual macronutrients and the optimum nutrient intake before, during and after training.

Part II: The individual macronutrients: protein, carbohydrates and fats

The source of protein - does it matter?

For now, we are mainly concerned with what we can do from a nutritional perspective to promote the signals necessary for protein synthesis to occur. Since amino acids are the building blocks of proteins, amino acid levels within the cell act as regulators for the mTOR protein complexes (10). Even in a positive energy state, protein synthesis will remain inhibited if the cell does not have the necessary amino acid stores.

A study conducted by Norton and colleagues concluded that the inherent leucine content of different protein sources (egg, wheat, soy and whey) resulted in different postprandial (i.e. after a food intake) plasma leucine levels and a different stimulation of muscle protein synthesis: only the groups consuming egg protein or whey protein showed a stimulation of protein synthesis beyond what could be observed in the control group without food intake (11). Therefore, we naturally want to consume a sufficient amount of amino acids and, more importantly, amino acids that activate mTOR protein complexes (such as leucine) (12).

To date, scientific research has shown that as long as a protein source has the necessary leucine content (and other essential amino acids), there are no significant differences in muscle protein synthesis between protein sources (e.g. milk, animal protein, egg protein, etc.) (13, 14).

The conclusion at this point is that the protein source is indeed important - but only in the sense that the protein source contains sufficient amounts of leucine and the essential amino acids. The difference in muscle protein synthesis rates is not significant if the leucine / EAA content is sufficient to maximize the muscle protein synthesis reaction. We will talk about the exact amounts later.

The amount of protein - is there a limit?

There seems to be a theory in the bodybuilding myth and legend world that the body can only digest X amount of protein per meal (for some reason this amount is supposed to be around 50 grams and apply to our entire species). Well, for lack of a more appropriate term, this theory is unfounded. The body can process significantly larger amounts of any macronutrient at a given meal, but the question we should be concerned with is how much of that dose results in a sustained rate of muscle protein synthesis. In addition, it would be interesting to know if there is an upper limit to postprandial muscle protein synthesis.

The last few years of scientific research have shed light on this. One example of this is the discovery that a combination of whey protein with supplemental leucine did not result in a significant difference in protein turnover compared to subjects who drank only whey protein (15). The caveat to these results is that they looked at total body-wide protein turnover and not just skeletal muscle protein turnover (for the purposes of body composition change, we are obviously not interested in hypertrophy of other body tissues such as liver or digestive tract).

Furthermore, another study concluded that the maximal activation (but not the duration) of muscle protein synthesis was proportional to the leucine content of a complete meal (i.e. a meal containing fat, carbohydrate and protein) (16). However, it has been found that one way to extend the duration of muscle protein synthesis is to supplement leucine (and/or carbohydrate) between meals (as long as the meals are spaced far enough apart to allow muscle protein synthesis to drop to its baseline, which is generally 4 to 6 hours after eating a large enough meal) (17).

It appears that a conservative estimate based on the available data is that 30+ grams of a leucine-rich protein source (such as most animal protein sources and whey protein) is sufficient to increase muscle protein synthesis rates for a good 3 to 4 hours (31). However, this is only a minimum baseline for active people and is by no means a strict rule.

Carbohydrates and the role of insulin

Many people seem to tend to go to extremes when it comes to carbohydrate intake, either advocating high carbohydrate intake or advocating a carbohydrate-free diet. Furthermore, there seems to be a lot of misconceptions about what exactly insulin does and how it affects fat loss and muscle hypertrophy.

First of all, even if you eat a carbohydrate-free diet, you will still secrete insulin - even amino acids are insulinogenic to some degree. In addition to this, a chronic low-carbohydrate diet does not appear to offer any metabolic benefits compared to a diet with moderate carbohydrate intake (21) and most studies have only shown benefits when very low-carbohydrate diets were used for short periods (22).

Secondly, insulin is indeed a storage hormone, but this is also the reason why it is highly anabolic. People seem to have this terrible fear of insulin and think that even the smallest amounts of this hormone will be enough to turn them into a Michelin Man. Don't be afraid of insulin! In fact, it's your ally when it comes to optimizing your muscle hypertrophy. Numerous studies have confirmed that the muscle protein synthesis response to a nominal dose of amino acids can be enhanced by the presence of sufficient amounts of carbohydrates (and thus an increased insulin response) (20, 23).

At this point, however, we must be careful not to overdo it. The key is to consume a sufficient dose of carbohydrates to promote a nominal insulin response, but not to try to stuff insane amounts of simple carbohydrates into you to increase insulin levels as much as possible. Insulin does not increase muscle protein synthesis in the physiological range in response to a meal in a linear fashion as many people seem to believe (24).

Pharmacological doses of insulin can indeed increase the muscle protein synthesis response beyond the normal physiological range, but this is not relevant in this context as it requires the use of exogenous insulin, which can quickly become very dangerous for inexperienced exercisers.

The bottom line at this point is that carbohydrates (and insulin) are your ally when it comes to optimizing muscle protein synthesis, but you should not overdo it and consume excessive amounts of carbohydrates, as the synergistic effect of insulin (in the physiological range) is not linear. You should consume a moderate amount of carbohydrates to efficiently stimulate insulin release (the specific amount per meal will depend on a number of factors, but there is no need to concentrate all your carbohydrates in one meal - not even after training).

Carbohydrate sources and glycemic load

For the majority of individuals who eat complete meals (i.e. meals that include fats, proteins and carbohydrates), the source of carbohydrate is less important than the total carbohydrate intake. The one exception would be individuals who consume excessive amounts of pure sugar (dextrose) at one time to maximize insulin levels, as indicated above.

There is no need to use pure high-glycemic carbohydrates to bring insulin levels up (and ultimately has minimal, if any, benefits). However, this does not mean that you need to avoid all simple sugars and high-glycemic carbohydrates, but simply reiterates the previously mentioned fact that a maximal increase in insulin levels (in the physiological range) does not increase muscle protein synthesis more than a moderate increase in insulin levels, as can be observed after consuming lower glycemic index (GI) carbohydrates such as oatmeal, sweet potatoes or other complex carbohydrates (24).

Another point to keep in mind is that the glycemic index (and ultimately glycemic load) of carbohydrates can be altered by consuming other food sources at the same time. Eating a full meal with a high-glycemic carbohydrate source will reduce the glycemic load of those carbohydrates as fat and fiber slow digestion.

As with most things in the world of nutrition, you should practice restraint and moderation when it comes to carbohydrates. Try to split your carbohydrate intake between different sources and don't exclusively eat sugar and other high-glycemic carbohydrates. Of course, it's okay to eat some sugar and other high-glycemic carbohydrates - but in reasonable amounts.

Dietary fats

Fats are unique in that they have a very high energy density (9 kcal per gram) and tend to be very satiating. They are essential for cellular integrity and play a role in a variety of cellular mechanisms. For these reasons, active people in particular should not consume too little fat.

Sources of saturated fats

Fatty acids consist of chains of hydrocarbons and when all carbon atoms are saturated with hydrogen atoms, these fats are called saturated fats. Saturated fats are usually demonized by the media and people who want to lose body fat, but they, like most other nutrients, have their rightful place in a healthy diet.

Coconut oil, for example, is made up almost entirely of saturated fat, but it is largely composed of medium-chain triglycerides, which are a form of fat that can easily be used by the body as an energy source instead of being stored. In addition, saturated fat intake appears to correlate with the production of sex hormones (androgens) in men (25).

But again, the key (just as with the insulin dilemma mentioned earlier) is that just because a nominal dose of something has benefits does not necessarily mean that a large dose is better. In fact, chronically high saturated fat intake is associated with insulin resistance and an increased risk of a number of metabolic disorders (26, 28).

Depending on your total fat intake and your goals, your saturated fat intake may fluctuate accordingly. A conservative estimate for the majority of active individuals is that at least 25% of total fat intake should consist of saturated fat. An imbalance of saturated and unsaturated fats is not desirable.

Sources of unsaturated fats

In contrast to saturated fats, unsaturated fatty acids contain either one (monounsaturated fatty acids) or several (polyunsaturated fatty acids) carbon double bonds (i.e. the carbon atoms are not saturated with hydrogen atoms). Monounsaturated fats are primarily found in nuts and vegetable oils. The popular omega-3 fatty acids are all polyunsaturated and are primarily found in fresh fish.

Numerous metabolic disorders have been linked to a deficiency of omega-3 fatty acids (27), which is why we should consume sufficient amounts of these specific fatty acids. The general consensus is that supplementation with 3.5 grams of omega-3 fatty acids (with a DHA:EPA ratio of 2:1) is sufficient for maintaining good health, although active people may require higher amounts (29).

Due to the overall health and metabolic benefits of unsaturated fatty acids, it is recommended that you consume the majority of your fats in the form of monounsaturated and polyunsaturated fatty acids (30).

Part III: Optimizing the Peri-Workout Nutrition Plan

Prepare. Perform. Replenish.

There are three relevant goals you should consider when putting together your training nutrition plan:

• Preparing the body for training
• Nourishing the body during training
• Replenishing the body's reserves and stores after training

Sure, these three goals seem pretty straightforward, but there are still multiple theories as to what constitutes the optimal approach in each of these situations. Of course, the growth and repair of muscle tissue is heavily dependent on proper nutrient intake.

As previously noted, it is difficult to give specific nutritional advice to a broad audience as each individual will have their own variables that may alter what is best for their performance and body development. Scientific research and anecdotal experience can give us general direction and guidance and personal customization will add the final touches.

It is important to remember that we are talking about optimizing the aforementioned three goals (prepare, perform, replenish.) that pertain to the individual in question. Thus, the optimal training diet will be relative to the individual and their specific needs/training goals.

The good news is that despite the inherent individuality of the nutrition aspect, there are some general protocols that are applicable to almost any person striving to improve their efforts in the gym. This guide will look at the basic principles of exercise nutrition and what scientific research considers to be optimal.

After establishing these fundamental points, this guide will provide guidance for further fine-tuning training nutrition based on the aforementioned individual factors that come into play. With this information in mind, we can now turn our attention to training nutrition protocols.

Phase I: Preparation

If you prefer to train on an empty stomach/fasting state, then there is no reason why you can't do this and still achieve excellent results. Whether training in a fasted state offers any significant metabolic benefits over training in a non-fasted state is highly debatable, but the anecdotal evidence I've seen from people following such a protocol is certainly promising. Training in a fasted state obviously involves not eating during the pre-workout phase, so feel free to move on to the next section of this guide.

Intuitively, many people believe that they should load up on carbohydrates before and during training as our bodies burn glucose for energy production. This is the basis of the conventional carbohydrate loading routine of endurance athletes the day before a sporting event, as the athlete wants to replenish their glycogen stores. If you look at the primary ingredient in the popular sports drink Gatorade, you'll notice it's dextrose (or another form of simple sugars). They throw a few electrolytes into the mix and voila, there's your energy in a bottle (metaphorically speaking).

Scientifically/theoretically speaking, loading up on carbs before an endurance event is a sound intention, but that protocol gets skewed when you throw other goals like maximizing muscle hypertrophy (as well as minimizing muscle catabolism), stimulating lipolysis, and increasing performance into the mix. And last time I checked, most figure class bodybuilders/athletes wanted to get as defined and muscular as possible - not become the next Steve Prefontaine.

The phase before training (or an important match) is ultimately the time to mentally prepare for the training (or competition) ahead. I would advise exercisers to eat food that is easy to digest and doesn't make them sluggish. How you perform after eating a meal is just as important - if not more important - than the physiological effect of that meal.

Think of it this way: if you're not able to perform well in the gym (or at your athletic competition) because you thought you'd have to choke down a bunch of food in hopes of accelerating your muscle growth (or improving your athletic performance), then you're actually doing more damage than if you ate a smaller meal and had an excellent training session (or a good competition).

Exactly what this smaller meal should look like varies from one person to the next. This meal should consist of foods that the individual can tolerate well so that they can maximize performance while stimulating an increase in muscle protein synthesis rates.

So the primary guideline at this point would be to make sure to eat a 20 to 30+ gram serving of leucine-rich protein and fill up the carbohydrate and fat portion of the meal according to your preferences.

Phase II: Perform

During your training sessions (or your competition) you may feel the need to consume some nutrients to keep your body in an "anabolic" or "anti-catabolic" state, but the reality is that if you have eaten an adequate pre-workout meal (1 to 3 hours before), you will not need to consume nutrients during your workout.

Some endurance athletes (and other athletes) may benefit from a simple carbohydrate solution (e.g. Gatorade) to replenish their glycogen stores. In addition, exercise promotes catabolism of EAAs (and specifically BCAAs), so the exerciser may benefit from consuming some EAAs/BCAAs during exercise, especially if they are exercising in a fasted state or if a significant amount of time (approximately 4 to 6 hours) has passed since their last pre-exercise meal (32).

A combination of carbohydrates and EAAs/BCAAs or whey protein would therefore be a viable option - but not a necessity unless the training session is very long.

Phase III: Replenishment

The theory regarding the "anabolic window" seems to send most exercisers into a rush to find the nearest protein shake as soon as they've shed the weight after their last set. However, the post-workout anabolic window is nowhere near as acute as most people seem to believe and, moreover, is not really as physiologically beneficial in the short term as many people think.

This doesn't mean that you don't need to eat after training. The industry seems to breed extremists, so I don't want you to get the idea that training intensely for 2 hours and then fasting for a day is in any way beneficial for muscle growth - because it's not.

Just think practically and use your head - try to eat your next post-workout meal when it fits into your schedule. If this happens 1 to 2 hours after your workout, you're fine - and no, you won't suddenly crumble into a pile of bone meal just because you didn't choke down a protein shake within 15 nanoseconds of your workout.

As for the spike in insulin levels during this period, it's not a necessity, nor does it provide any great additional benefits. If you don't have time to eat a solid meal within the first few hours after training, then take a protein shake and some carbs/fats with you on the go. Another option is to take some EAAs/BCAAs after your workout to tide you over until your next meal. This is particularly advisable for those who train on an empty stomach and can't eat for several hours after training.

Final thoughts

Some readers may be a little annoyed to have read this entire guide without finding any of the typical quantitative recommendations regarding the perfect pre-workout ratio of carbs : protein : fat or whatever. If you still don't understand why I've refrained from making such sweeping statements, let me reiterate that there is no such thing as a predetermined universally perfect diet. The permutations of perfect dietary protocols are infinite, so I wouldn't even know where to start with sample plans.

My goal with this guide was to give the reader a basic knowledge of how the body responds physiologically to training and nutritional intake so that you can apply what you learn to your own life/training. The possibilities are truly endless and you will eventually find out for yourself what is optimal for your lifestyle and diet.

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