When it comes to the discussion of improving performance and fitness, one can't forget about the role of a proper diet and how much our day to day nutrition affects how we feel and perform. I've been going into detail about training periodization in my last few articles, and periodization for nutrition is something I've been planning to bring up as well.

So what is nutritional periodization, or periodized nutrition? Simply, planning and structuring of a diet based on the goals and demands of a trainee or athlete. Since training variables like intensity, volume, competition schedule and practices change from season to season and one training cycle to the next, nutritional periodization must be used and adapted according to the demands of practice, training and competition.

Scientifically, we know nutrition has a large impact on training outcomes and adaptations.

Consistently working out, but still consistently eating too many calories? You're not going to lose weight.
On a hypertrophy program but you're not consuming enough protein? You're not going to get big!
Not drinking enough water? You'll become dehydrated and performance will suffer.
Going low carb and constantly training with high intensity? You're not going to achieve the high intensity endurance you want.
etc....

How exactly it affects all these training outcomes and their subtle nuances,are still not clear as research in this field is still relatively new.

There's a review article on this topic that just came out yesterday (Mar 22nd 2017), titled "Periodized Nutrition For Athletes" by Asker Jeukendrup, a respected nutrition-researcher and Professor from the Netherlands. In the article, Jeukendrup discusses the historical aspects of nutrition and diet as they relate to training and exercise, and also lays down the foundation on what periodized nutrition means and what it's role is. He reviews an impressive list of various nutritional methods such as training on low carbohydrates, high carbohydrate diets, ketogenic diets and also a few supplements.

Here is the list below:

Without trying to repeat too much of what Jeukendrup says in the review paper (I highly urge you to read it if you're serious about improving your knowledge on nutrition - again here is the LINK : OPEN ACCESS), I wanted to talk about a few of the methods, particularly the more popular ones related to mainstream nutrition and dieting.

Some of the methods listed above might be considered "fad diets" in some circles; there has been a lot of talk about fasted cardio, is which essentially training low - training fasted, and ketogenic diets lately. Specifically, how they don't work and how they're bullshit and no one should be on them. While they might be right in some circumstances, its always good to have a change of perspective and see in which scenarios these nutritional methods can be beneficial. It's all about context.

fasted cardio (Train low - training fasted)

Fasted cardio, or performing a cardio-endurance activity in the morning without having breakfast, has been touted to help burn fat and help trainees lose weight by forcing your body to use more of your "stubborn" fat as energy during exercise. Unfortunately, consistently working out with an empty stomach can be a terrible choice.

For most trainees, fasted cardio will simply feel terrible and their workouts suffer, causing them to exercise less intensely and expend less calories than they would normally. Since we know that weight and fat loss is primarily driven by calorie balance, the form and method of cardio that allows us to consistently burn off a high amount of calories and can be sustainable for the trainee, is the best form of cardio. For a lot of people, this means a snack or light meal prior to a workout, and exercising at various different intensities to keep things fun and interesting.

Fasted cardio is popular amongst bodybuilders, and people still do lose weight performing fasted cardio, does this mean fasted cardio is useless at best?
For the fitness and weight loss demographic, yes. But remember, context matters. Fasted cardio can be a nutritional method for amateur and professional endurance athletes to improve their endurance.

The sleep low method is a good example of a fasted cardio method (sleep low method studies - study link #1 here, #2 here), where the objective is to eliminate carbohydrate intake prior to sleeping, and fasting up to your morning training session. Training in the absence of carbohydrate (almost) or with a low-carbohydrate availability in your muscles or your liver, can promote the expression of certain genes like AMPK to amplify the adaptations from endurance training, like increaesed mitochondria and oxidative enzymes. However, there's a caveat.

These adaptations are amplified only if training is done at the lower intensities, the aerobic zones in which fat is the primary fuel source. The sleep low method does not work and can be detrimental if the morning fasted cardio session consists of prolonged moderate intensity exercise or high intensity intervals, as carbohydrate/glucose is a much more preferred source during harder efforts of cardio training. Sleeping low or performing fasted training sessions will greatly reduce the quality of your workouts and the progress you'll make. Since not all training sessions will be high-intensity in nature, training fasted or on low glycogen can actually be applicable in some scenarios.

Proponents of fasted cardio believes training while hungry will help improve mental toughness, this is particularly popular in combat sports. I believe there are other ways to improve mental toughness without reducing the effectiveness of your training sessions though.

Now we start to see the carryover and the synergy between training periodization and nutritional periodization.

Doing block periodization and you're in a very high-volume, low-intensity endurance block? It might be effective to try out low-carb methods for the training block.

Peaking for a competition that requires high intensity intervals? Probably a smart idea to carb up.

Certain methods work for certain groups of people. Just because a diet works for you, doesn't mean it'll work for someone else, and just because a diet DOESN'T work for you, doesn't mean it won't be effective for someone else.

Ketogenic diet

We just talked about low-carbing or fasting before workouts. How about going low carb for a few months? For life?. Enter the ketogenic diet.

By significantly reducing the amount of daily carbohydrate intake (<50g), we go into a state of ketosis, where our body utilizes fats and ketones as your primary fuel source. Sounds similar to the fasted cardio method, but this takes an athlete several weeks to become fat-adapted, therefore affecting exercise and body composition on the longer-term. Is it useful? Is it effective?

We can look at it from different angles:

Keto for someone looking to lose weight:

In this situation, we have to take into consideration their ability to sustain a diet with low-carbs. Many of the foods today world contain carbohydrates and it is often hard to skip meals with your friends and family. Consuming a bit too many carbs can bring you out of ketosis and make you feel worse. You don't want to be in no-man's land - where you're not consuming enough carbs to fuel your daily life and exercise, and where you're consuming too many carbs to be in a ketogenic-state.

Diet sustainability is a big factor, paired with the fact that trainees still have to be eating in a calorie deficit. Knowing what fat and protein sources to eat is also something that must be learned if a keto diet is to be sustained in a healthy manner. Many people can't effectively lose weight and keep that weight off with a ketogenic diet. The ones that can, great for them. Find what works for you in terms of weight loss. I recommend reading or buying "The Ketogenic Diet" by Lyle McDonald, he has written extensively on this topic and how to properly go on a ketogenic diet for fat loss, performance and body composition goals.

Keto for a competitive athlete:

Jeukendrup's review paper and numerous other studies state that a keto athlete has dramatically increased fat utiliziation ability and upregulated enzymes involved in fat oxidation. However, some of the same studies that showed there was no improved performance effects regardless of the fact fat oxidation potential was increased.

There are a lot of successful keto athletes though, it just depends on the type of sport.

Like I alluded to earlier, exercises or sports that utilize lower heart rates and intensities will pair best with a low-carb method or approach. While fat isn't a quick source of energy like glucose and phosphocreatine is, it can provide a lot of energy, 9kcal/g. This is viable for sports that are low intensities in nature but require a lot of energy, such as ultra-marathons and other long endurance events.

This is not to say a calorie-matched high carb diet won't be more beneficial. Ketogenic athletes have shown to have a reduced ability to utilize carbohydrates as the enzymes related to carb metabolism are compromised when going on prolonged periods of carb restriction. Not so great for many team sports or endurance events that require repeated short bursts of high-intensity.

edit: A 2017 study looking at race walkers on a ketogenic diet showed reduced economy, impairing performance. <Study here>

Supplements and drugs

By far the most popular method to improve fitness and performance goals. Supplements are the first thing many people and athletes turn to as they are marketed to quickly improve performance, help build muscle and shred fat.

There are a lot of ergogenic supplements that have been studied extensively (have to plug Examine.com here, best website for information and research regarded supplements) to be shown to have health and fitness benefits, protein supplements, creatine, Vitamin D3, beta-alanine, to name a few.

There are also many supplements that have been shown to underdeliver, and are ineffective. Some of which are used incorrectly, but most of which flat out don't work as claimed to.

Supplements and drugs can also reduce training adaptations and be detrimental to performance, like antioxidants and anti-inflammatory drugs.

Everyone should always be skeptical when it comes to supplement, to due it's unregulated nature and often times skewed research results. Take everything with a grain of salt and remember to master the basics before considering taking a shelf full of pills and powders.

From my article on pyramids in fitness and nutrition.

Supplement usage should be considered on a case by case basis, with context in mind.

Concluding thoughts

Fitness and performance is not 80% training, 20% nutrition, or whatever.

It is 100% training and 100% nutrition, they work synergistically and are co-dependent. Training outcomes depend on the fuel you're putting into your body as much as nutritional interventions and methods depend on the your training goal and demands.

The better sport nutritionists understand training periodization, the better nutrition can be provided according to the demands of the athletes. The more well-versed strength & conditioning coaches are in nutrition, they better they can influence the performance and recvoery of the athletes.

Keep this in mind when evaluating and considering supplements and diets. Be on the look out for more interesting research papers on sports nutrition in the years to come!

5-Part Periodization Series Links:
Read Part 101: Introduction
Read Part 201: Training Variation
Read Part 202: Training Effect & Phases
Read Part 301: Review of Periodization Models
Read Part 401: The Complexities and Problems of Periodization Theory