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Complete Nutrient Intake Guide for Athletes

Complete Nutrient Intake Guide for Athletes

Timing and amount of intake of macronutrients in the athlete’s diet need to be anchored to a fundamental awareness of how training-nutrient interactions affect our client’s physiology, including their energy systems, substrate availability- ability and training adaptations. 

In order to maximize the effects of strategically timed macronutrient intake, we have to be well-informed about how energy systems operate. 

Available stores of liver glycogen, intramuscular lipid, adipose tissue triglycerides, and amino are the necessary substrates in foods athletes consume. Their presence, or lack of, can be determinants in the training adaptations our client experiences. Remember, energy systems are integrated with nature, meaning that they do not work alone. 

Adenosine triphosphate (ATP) and phosphocreatine (also known as the phosphocreatine system) provide a quickly available energy source for muscular work but at insufficient levels to provide continuous energy for activities lasting longer than 10 seconds in duration. The anaerobic glycolytic pathway rapidly metabolizes glucose and muscle glycogen through the glycolytic pathway and can fuel activities that are higher intensity as the primary pathway, pro- viding energy for exercise lasting anywhere from 10–180 seconds in duration. Beyond this time frame, the oxidative pathways provide the primary fuels for events lasting longer than ~2 minutes, since neither phosphagen nor the glycolytic pathway can sustain energy demands that allow muscles to contract at a very high rate for longer intervals. During these energy-producing actions within our physiology, the major substrates involved (mentioned above) must be present in muscle, blood, liver, or the gut. 

When oxygen is plentiful and is more available to the working muscle, the body uses more aerobic (oxidative) pathways and less of the anaerobic (phosphagen and glycolytic) pathways. The greater dependence on aerobic pathways does not happen quickly and of course, no single pathway is ever relied on to be the sole provider of energy. Other factors, such as intensity, duration, frequency, type of training, gender, and training level of the individual – as well as prior nutrient intake and substrate availability – determine the relative contribution of energy pathways and is therefore seen as a gatekeeper for when crossover between energy pathways is occurring. 

Aerobic Energy vs. Anaerobic Energy 

To ensure that energy balance and availability are maximized, achieving proper substrate availability should be considered required as a best practice. As a training adaptation, it sounds simple. But if you cannot explain this to your client succinctly, you may need to brush up on verbiage and some of your conversation skills when sharing scientific information with a client. Just as skeletal muscle adapts to what is loaded upon it, there is also an adaptation effect that is based on the current nutritional status of the athlete, which then results in conditioning-specific adaptations. These are both metabolic and functional in nature. 

Carbohydrate (CHO) The Greatest Macro? 

The role of CHO in training is vast. CHO stores are relatively limited for humans but to make things more interesting, intake of this macronutrient can be so finely tuned that a nutritionist or SNS may address CHO intake on a daily basis for even a single bout of PA. 

Much more than just fuel for the brain and central nervous system (CNS), its ability to act as a substrate for activity in a wide range of intensities makes us put so much focus on it. Even when our athlete trains at the highest intensities, carbohydrate offers advantages over fat as a substrate because it yields more ATP per volume of oxygen that can be delivered to the mitochondria, thereby improving exercise energy efficiency. 

Inadequate carbohydrate levels available for the central nervous system impair performance-influencing factors such as pacing, perceptions of fatigue, motor skill, and focus/concentration. 

When explained this way, we can also say that prolonged and sustained intermittent exercise at high-intensity levels can be enhanced if we can get our athletes to efficiently store a level of CHO availability as part of a maintenance plan – to always have a steady supply. The challenge here is to know just how much to take in without it being stored as energy (fat) in the body. Manipulating the storage of CHO in the body is a finely tuned science. 

So, we know that body carbohydrate stores are relatively limited and can be manipulated acutely either by dietary intake on a daily basis or even for a single session of exercise. Carbohydrate is the preferred fuel for the brain and central nervous system, it also serves as an important substrate for muscular work. Furthermore, the availability of carbohydrate stores is limiting the performance of prolonged continuous or intermittent exercise and allows for the performance of sustained high-intensity sport. 

Individualized recommendations for daily intake of carbohydrates should be made in consideration of the athletic training/competition program and the relative importance of undertaking it with high or low carbohydrates. 

The precise timing of carbohydrate intake over the day while in relation to training can also be manipulated to promote or reduce carbohydrate substrate availability. Eating strategies are more effective when they promote adaptations such as gastrointestinal tolerance and enhanced intestinal absorption because they may allow competitive athletes to be properly fueled and more effective. 

Achieving adequate muscle glycogen stores requires manipulating nutrition and exercise in the hours and days prior to an important exercise bout. This allows an athlete to begin a training session or event with glycogen stores that are matched with the estimated fuel costs of the event. For example, carbohydrates consumed in meals and/or snacks during the 1–4 hours pre-exercise may continue to increase body glycogen stores, particularly liver glycogen levels that have been depleted by the overnight fast. 

Because the intake of carbohydrates prior to exercise is not always straightforward, you will be faced with finding intake recommendations and strategies that suit your athlete’s current training situation and their past experiences. Once this is known, you can fine-tune recommendations with further experimentation. 

Generally, to prevent premature fatigue resulting from low CHO stores paired with greater CHO oxidation levels, you might begin by recommending at least 1 g/kg BW of carbohydrate in the pre-event meal to compensate for the increased carbohydrate oxidation as well as including a protein source for the meal. Additionally, choosing pre-exercise meals from carbohydrate-rich foods with a low glycemic index may reduce the metabolic changes associated with carbohydrate ingestion as well as provide a more sustained carbohydrate release during exercise. The application of this knowledge is part of what is required for both your athlete and you to be successful. 

The intake of carbohydrates during exercise provides a number of benefits to exercise capacity and performance using systems that include glycogen sparing, provision of an exogenous muscle substrate, prevention of hypoglycemia, and activation of the reward centers in the central nervous system. Research on PA carbohydrate intake has led to the belief that different amounts, timing, and types of carbohydrates are needed to achieve these specific effects of training these effects can be very different but may still overlap in various events. 

Glycogen restoration will always be one of the main goals of post-exercise recovery, particularly between bouts of PA considered carbohydrate-dependent routines, where there is a priority on performance in a second session – or beyond – later in the day. Refueling requires adequate carbohydrate planning of both intake and times for this type of training. 

In some training environments, one strategy used is deliberately exercising with low carbohydrate availability to enhance the training stimulus or adaptive response – or as others believe to only burn fat. Various strategies can be used to permit or promote low carbohydrate availability, and this is managed by the Specialist after considering all the factors you have assessed – the client, the sport, and the goals. This strategy relies on reducing total carbohydrate intake or manipulating the timing of training in relation to carbohydrate intake. This would be useful for one who is training in a fasted state or one who may be doing two bouts of exercise in proximity without refueling between sessions. When the focus becomes one of enhancing training stimulus or adaptations or responses, low carbohydrate availability may be deliberately achieved by reducing total intake or by changing CHO intake based on training sessions during the day or week. This would be more of an ongoing application of the strategy, however. 

In the fitness industry more so than anywhere, carbohydrates may be the most controversial of all macronutrients. But coaches who train and Specialists that advise clients at a higher level of intensity have a decidedly easier time getting their clients to consume CHO. These clients understand its importance. It can be harder to redirect a client who may have success with another method of their own from their past experience, or one who is susceptible to information presented by sources not considered reputable. 

Therefore, you are tasked with making recommendations to prevent the depletion of CHO stores, as it is associated with fatigue in the form of reduced work rates and performance, impaired skills and concentration levels, an increased perception of effort. If we do not, we may adversely impact the performance of our athletes. 

From a recovery perspective, glycogen is an important factor, having both direct and indirect roles of regulating the muscle adaptations to training. The amount and localized presence of glycogen within the muscle cell will alter the physical, metabolic, and hormonal environment in which signaling occurs to hormonal responses in response to exercise. 

Carbohydrate Use by the Body 

As the body’s primary source of energy, the human brain relies exclusively on CHO intake for function. The recommendations you make for kilocalorie (Kcal) intake for an athlete should include healthy sources of carbohydrates and of course, fiber. It is essential for the Specialist to identify which sources are the best for the client; this will be based on your assessment of what they know, what they have access to, and even where they are in their training periodization. You are also allowed to inform a client as to how normal values for CHO are estimated, helping them discover how much CHO to consume and the proper timing. You can also recommend types of intake (simple versus complex). 

Carbohydrates exist as either monosaccharides (glucose, fructose, and galactose) or disaccharides (maltose, lactose, and sucrose). These are commonly referred to as “simple” carbohydrates” and “Complex” carbohydrates are formed when three or more glucose molecules come together. A polysaccharide is made up of 10 or more glucose molecules. Simple and complex carbohydrates have different digestion times and this is important for how both types can play a role as part of a strategized nutrition plan that accounts for athlete comfort as well as performance. 

Along with fat, carbohydrates provide most of the energy for the body to function. The level, length, and intensity of activity determine whether carbohydrates or fat will be used preferentially. For example, at rest, 15-20% of muscle energy comes from fat, but during intense exercise (greater than 85% VO2 max) carbs are responsible for the majority of energy production.1 Ideally, calorie and macronutrient intake are appropriate and what the body needs is readily available for energy production. 

If the intake is falling short and carbohydrate needs are not being met, the body must work harder to convert other nutrients to glucose for ATP production. 

When carbohydrates are consumed, some are used immediately and the rest is stored for later use in the form of glycogen. The two storage sites for glycogen are muscle and liver cells. For a typical sedentary adult, the liver can store approximately 300-400 calories and the muscle can store 1200-1600 calories. Training can increase these stores, allowing for additional energy storage and under normal conditions, a very small amount of glucose (about 20 calories) can also be found in the blood. When energy is needed, metabolic processes mobilize glycogen to produce ATP and give the body fuel. 

Carbohydrate Advice for Your Athlete’s Diet 

Sources of carbohydrates include fruits, vegetables, grains, and sweets. Foods like beans and dairy products also contain some carbohydrates. Fruits, vegetables, whole grains, and beans also contain fiber, a form of complex carbohydrate that takes longer to digest. 

Some guidelines to be aware of when making any food choice recommendations include: 

  • Taste preference – choose foods that are pleasing to personal taste 
  • Nutrient density – foods with a high amount of nutrients 
  • Digestion time – how long will this food take to digest before activity? 
  • Personal tolerance – individuals digest differently, athletes need to choose the food they know they can digest without a problem (there might be some trial and error involved to get this correct) 

When providing intake suggestions, athletes are best advised to choose nutrient-dense carbohydrates like whole grains, fruits, and vegetables. Beans, also a source of protein, are great due to the fiber they contain and dairy products will also provide some protein along with carbohydrates. The recommendations for fiber do not exceed those of the general population but it is necessary to hit the gram total each day so that the digestive system remains healthy. Some high-fiber foods can cause stomach upset, especially in a nervous athlete. Like fat and protein, choices that are high in fiber should be avoided to reduce the risk of gastrointestinal issues during the event or competition. 

As a nutrition specialist, you must understand that activities performed at higher levels of intensity generally require that higher CHO be available. We also want to watch for problems associated with low stores of CHO (fatigue, etc.). The role of glycogen in regulating muscular adaptations requires that you follow sensible guidelines for making individualized recommendations, based on science, the individual needs of your client, and what the research currently tells us about CHO. 

Protein Intake 

Protein (PRO) plays several important roles in the athlete’s body but unlike carbohydrates and fat, protein is not a primary energy source. Protein’s job is to build and maintain muscle mass and to help regulate metabolism. These functions are by no means less important than energy production, but since the body does not store protein efficiently, it is needed in smaller amounts than the other macronutrients. 

Amino acids are the building blocks of proteins. There are twenty unique amino acids that combine in various ways to form the proteins that the body re- quires. Nine of these amino acids are dubbed “essential” meaning they must be obtained from the diet. The remaining 11 amino acids are “nonessential” meaning they can be produced by the body. Under certain circumstances, the body’s demand for some of these nonessential amino acids is too great, and more is needed from the diet, these are referred to as “conditionally essential.” Of the amino acids, leucine, isoleucine, and valine (also referred to as the branched-chain amino acids related most significantly to muscle tissue.) 

The Function of Protein

The primary functions of protein are the formation and repair of muscle tissue, enzyme production, and regulation of metabolism. Protein can be an energy source during exercise when needed but is not a very efficient way to produce energy. Proteins and amino acids are also involved in hormone and immune function, as well as fluid and acid-base balance. 

Dietary protein is broken down into individual amino acids, which are then mixed and matched as needed to satisfy the body’s protein needs. Since excess protein is not stored, residual amino acids are broken down and most are removed from the body. Some remnants are utilized while the rest is excreted in the urine. 

Protein in the Athlete’s Diet 

Recent recommendations demonstrate the importance of well-timed protein intake for all athletes even when muscle hypertrophy is not the primary training goal, and research now suggests validity to the practice of recommended daily protein intake totals that seek to maximize metabolic adaptations to training. This means that the timing, amount, and type of carbohydrate foods and drinks should be chosen to suit the practical needs of training and individual preferences/ experiences. 

Current data suggest that dietary protein intake necessary to support metabolic adaptation, repair, remodeling, and protein turnover generally ranges from 1.2 to 2.0 g/kg/d. Higher intakes may be indicated for short periods during intensified training or when reducing energy intake Daily protein intake goals should be met with a meal plan providing a regular spread of moderate amounts of high-quality protein across the day and following strenuous training sessions. 

Your guidelines, instructions, and recommendations made to your athlete client should be based on the need for optimal adaptations to specific sessions of training/competition within a training plan or periodized program. Additionally, it has to be anchored by an appreciation of the larger context of athletic goals, nutrient needs, energy considerations, and typical food choices. 

The requirements for your athlete can fluctuate based on such variables as training level and condition status, training sessions (involving greater frequency and intensity), or a new training stimulus at a higher end of protein need. The availability of CHO and usable energy require the right levels of consumption for adequate energy. This is particularly true of carbohydrates. When you can match energy expenditure with CHO intake, amino acids are spared. This means that amino acids can be used for protein synthesis and are not oxidized. 

What the Research is Telling us About Protein 

Laboratory-based studies show that muscle protein synthesis (MPS) is optimized in response to exercise by the consumption of a high bio-available protein, providing ~10 g of essential amino acids in the early recovery phase post-exercise (0–2 hours post-exercise). When you calculate the required intake to target MPS, a recommended protein intake of 0.25– 0.3 g/ kg body weight or 15–25g protein is appropriate. This is also true across the typical range of athlete body sizes, although athletes at extreme ends of the weight spectrum may need this guideline fine-tuned for them. 

Research is also suggesting that higher doses have not yet been shown to further augment MPS and may only be prudent for the largest athletes, or in a weight loss phase. The exercise enhancement of MPS can be directly orchestrated by you. This is done by determining the timing and pattern of protein intake. You monitor and evaluate how the client responds to other variables, such as intake of protein within the 24-hour period, and post-exercise. These guidelines are more appropriate when the goal of your athlete is to increase MPS over a meso or macrocycle. 

However, long-term training studies currently suggest that increases in strength and muscle mass are greatest with a more immediate post-exercise provision of protein. 

Protein Pairing and Timing 

Protein consumption in the immediate pre-and post-exercise period is often intertwined with carbohydrate consumption as most athletes consume foods, beverages, and supplements that contain macronutrients. It is also a strategy commonly used to enhance and accelerate glycogen replacement. 

Increases above the RDA for protein are common for athletes; the added amount in grams is seen to benefit athletes who are involved in multiple training or competitive sessions over the same or successive days. More research is needed to understand if this is potentially done to elevate protein intake levels and also support glycogen resynthesis in the post-workout period. 

Interestingly enough, protein ingestion during exercise and during the pre-exercise period seems to have very little effect on MPS than when consumed in the post-exercise window. The latest research indicates that consuming protein and carbohydrates during 2 hours of intermittent resistance-type exercise has been shown to stimulate MPS during the exercise period and may extend the metabolic adaptation window – this is particularly true of ultra–endurance-type exercise bouts. 

Protein Overview 

When looking at protein as a percentage of overall calories, the recommendation is typically 10% to 35% of total intake. Current data from the research shows that both males and females (19-70 years of age) eat approximately 15% of total calories from protein. This is within the 10% to 35% recommendation, but with the proven positive benefits of higher protein intake on satiety and other physiologic functions, efforts should be undertaken to help athletes consume 

the recommended amounts of protein. It may even make sense to consider increasing protein intake recommendations even further, to 25% to30% of calories, a level that is still within the AMDR 

The AMDR represents a fairly large range for intake; The DRI, RDA, EAR, and AI were all derived using a collection of data based on nitrogen balance research trials, with energy balance factored in as a controlled variable. The Institute of Medicine’s Dietary Reference Intakes (DRI) for protein include the Recommended Dietary Allowance (RDA), Estimated Average Requirement (EAR), and the Adequate Intake (AI). Remember, the current RDA for all adults aged >19 years of age is just 0.8 g/kg of body weight. 

Nutrition experts believe that this value represents more of a baseline, or a minimum level of protein to offset the negative nitrogen balance in 98% of individuals. The RDA, for a majority of advanced athletes, is a little on the low side; therefore, make recommendations that are still sensible but never contraindicated. Remember, processing excess protein from the body is not a desirable state for our athletes to be in. For eating plans that have relatively large kcal values, this is welcome news, as the increase in kcals can come from lean protein. This elevated protein intake seems to benefit older adults as well. 

Protein Intake and Timing 

There may be some dynamics related to food intake where your athlete client may need changes in order to be successful. Consider that recent research has moved beyond examining the optimal amount of protein to eat to examine the optimal times to consume it. Considering that your athlete has protein needs throughout the day, there may need to be a shift to consume protein more regularly, throughout the day. In many Western diets, protein consumption is relatively high in the evening, whereas breakfast typically consists of carbohydrate-rich and low protein totals. The meals consumed in the evening are also much higher in calories. This may not be your client’s goal; they may also be very disorganized in their eating patterns. You will see it all and you may need to help clients change this behavior when it is contraindicated toward their goals. 

Protein Quality Matters 

When we talk to our clients about protein, we have to encourage an emphasis on quality. While a formal definition for “high quality” protein doesn’t exist, there are some quick and easy methods to determine dietary protein quality. Generally speaking, complete proteins that provide all the essential amino ac- ids are considered “high quality.” These include foods like beef, fish, poultry, eggs, dairy (including milk, cottage cheese, Greek yogurt, whey protein, and others) and soy. One amino acid in particular – leucine – is important. 

What is leucine and why does it matter? 

Leucine is a particularly interesting amino acid, as the leucine concentration in a protein ultimately determines the optimal amount of protein per meal. Leucine is the “rate-limiting” amino acid in muscle protein synthesis (building and maintaining muscle). Proteins with higher (vs. lower) leucine quantities are more effective at stimulating muscle protein synthesis. One hypothesis is that there is a “leucine threshold” where protein with higher versus lower leucine quantities has more effectiveness in stimulating muscle protein synthesis. More specifically, data and consensus show that no lower than 2.2 or higher than 3.0 grams of leucine per meal is required to maximize muscle protein synthesis. These numbers are of critical importance because research suggests if a meal has less than 2.0 grams of leucine, instead of being used for muscle protein synthesis, the protein will be used for energy. This brings us back to quality, not just quantity. 

Measuring Leucine Content in Foods 

While it is easy to get the recommended amount (2.2 to 3.0 grams leucine) with some protein supplements, being sourced from real food is always preferred. And, sometimes even better. In fact, as you see below, cottage cheese is one of the highest food sources of leucine, providing 2.9 grams for 1 cup (about 28 grams of protein). Several others are listed for reference. 

Meeting Daily Protein Needs 

Since the key is to remember that protein intake is not just about quantity, the important part is to focus on the frequency and quality of the protein itself. The goal of eating 2.2 to 3.0 grams of leucine within each meal to maximize protein synthesis and get the most out of the protein you eat, can go a long way to support the benefits of protein. 

Applying New Research to Coaching Plans 

While it is important to discuss specifics about protein quantity, timing and quality, at the end of the day, what does this mean for your clients? 

  •  Educate and inform your athlete on eating high-quality protein options, especially in the morning. 
  •  Suggest clients aim to eat one palmful size portion of quality protein at each meal – almonds are a great example. This will provide approximately 20 to 30 grams or protein). 
  •  Encourage athletes or players to decrease their portion of protein in the evening, when most people are eating significantly more than their body can benefit from. This is especially true if weight loss is a goal. 

While only a very small portion (approximately 5%) of protein in the body should be metabolized for energy, carbohydrate intake will directly affect how protein is utilized. When there is adequate carbohydrate in the diet, protein will be reserved for its primary functions. Due to the benefits of protein on metabolism overall, the guidelines include this awareness and increase protein well above the RDA with all clients, not just those with hypertrophy as a goal. 

As mentioned previously, muscle tissue requires protein for repair and recovery within 30 to 60 minutes post-workout. Carbohydrates should also be present to replace glycogen (stored energy in the muscle tissue). Aim for about 20-30 grams of protein after a workout. Recommendations should include a pattern of at least 20-30 grams regularly throughout the day. To help support this pattern, you will notice the values are very similar for each instance of intake, the range does not vary a great deal. 

Athletes often complain of not being hungry immediately after an exercise session. In these cases, liquid calories may be tolerated better. A fruit and yogurt smoothie, protein shake, or serving of chocolate milk can give athletes the nutrients they need. 

Recovery Time – Combining Macronutrients For Great Results 

Since we know that CHO will affect PRO use, try an 8 oz. glass of low-fat chocolate milk or a turkey sandwich on whole-grain bread. Cottage cheese is another popular recovery option, and the milk-based protein is perfect when paired with fresh fruit. The high yield of PRO in Greek yogurt makes mixing it with fruit and granola a perfect companion to apple wedges and natural peanut butter. Be creative, and work with your athlete client’s preferences. 

Providing recommendations to your athlete has to include these vital building blocks found as essential and nonessential amino acids. Know what and why you are making recommendations so that you can inform your client about their nutrition intake. Suggest foods from a variety of sources including lean meat, fish (including some cold water Omega 3/6 rich types), poultry, dairy, eggs, and legumes (among others). Keep intake values in the daily range of 1.2 to 1.7 grams per kilogram body weight, with approximately 20-30g of PRO intake at each meal for balance. 

Recent studies have shown that consumption of milk-based protein after resistance training is effective in increasing muscle strength and favorable changes in body composition. In addition, there is some evidence of increased MPS and protein stores with whole milk, lean meats, and dietary supplements. This may be due to these proteins providing isolated proteins (whey, casein, soy, and egg). Currently, dairy proteins are seen as superior to other proteins evaluated, due to leucine content and the digestion actions of branched-chain amino acids in liquid dairy options. 

Fat Recommendations 

Like carbohydrates, fat is a vital energy source, even when the body is in a rested state. During exercise, the body’s preferred energy source is dynamic; in- creasing intensity during exercise or conditioning will also create shifts, based on the needs of the activity. This shift stays in a fluid state throughout the activity. This suggests that stores of both CHO and fat can become determinants of supporting the most efficient outcome or performance. 

Fatty acids are the basic building blocks of fats. The most significant portion of fat in the diet comes in the form of triglycerides, three fatty acids attached to a glycerol molecule. Fatty acids (made from molecules of carbon, hydrogen, and oxygen) combine to form “chains” of various lengths. Some chains are saturated with hydrogen and others remain unsaturated. Unsaturated fats can be further separated into “mono” or “poly” designations, depending on their structure. Both mono and polyunsaturated fats are considered “heart-healthy.” Many sources of dietary fat are made up of combinations of both saturated and unsaturated fats. 

Like the “essential” amino acids, essential fatty acids must be obtained from the diet. Two of the most important types of essential polyunsaturated fats are omega-3 (alpha-linolenic acid) and omega-6 (linoleic acid). 

Proper fat intake ensures adequate energy reserves, allows for the absorption of fat-soluble vitamins (vitamin A, D, E, and K), facilitates nerve conduction, and helps regulate body temperature. Omega-3 fats are important for brain function, immunity, as well as skin, eye, and heart health. Omega-6 fats also play a role in brain function and contribute to growth and development. 

Fat breakdown, absorption, and transport are more complicated than carbohydrates and protein because fat does not dissolve in water (and the body is mostly water). Since additional steps are required, the digestion of high-fat meals and snacks can take several hours. Athletes need to keep this in mind when making meal choices surrounding workout times. 

In muscle tissue, digested fat is used immediately for energy or stored for later use in the muscle and adipose tissue. 

VO2 max and Fat 

Exercise intensity can be expressed as a measure of oxygen consumption (VO2 max). As exercise intensity changes, so do the body’s preferred energy source. During a lower intensity activity (25% VO2 max), the majority of energy comes from fat. At 85% of VO2 max, the body stores carbohydrate is corralled for use. When intensity is at a more moderate level, (approximately 65% VO2 max) CHO and fat contribute equally. Since exercise intensity changes dramatically throughout our athlete’s training regimen, we know that these energy systems are constantly shifting, they are not static. When dietary intake of any micro-nutrient is inadequate these systems (and performance) can be compromised. 

Fat in the Athlete’s Diet 

Healthy options for fats include plant-based oils like olive, canola and sunflower, nuts, and seeds; peanut butter, cheese, fatty fish such as salmon and tuna are also tasty, nutrient-dense choices. The proportion of energy from saturated fats should be limited to less than 10% of the total Fat intake value, including sources of essential fatty acids to meet Adequate Intake (AI) recommendations. 

Protein sources like low fat or full-fat dairy, egg yolks, and meat also contain some fat, and much of this fat is saturated. Since these foods offer many other healthy nutrients like protein and calcium for example, it’s recommended to incorporate them into a healthy diet. Most saturated fats are solid at room temperature and come from animal products; some exceptions would be palm oil and coconut oil. 

Sources of omega-3 fats include leafy greens vegetables, flaxseed, canola, soy, walnuts, and cold water seafood, like salmon. Omega-6 fats can be found in vegetable oils including corn, soy, peanut, and sunflower oil; many of these can be found in margarine spreads and salad dressings as added ingredients. 

Since fatty acid utilization can be enhanced by dietary strategies such as fasting, intake of fat, and chronic exposure to high-fat, low-carbohydrate diets, exercise-induced adaptations do not appear to maximize oxidation rates solely or as plentifully. Although there are many interested in what they believe to be chronic adaptations to high-fat low carbohydrate diets, the present evidence suggests that enhanced rates of fat oxidation can only match exercise capacity/performance achieved by diets or strategies promoting high carbohydrate availability at moderate intensities.4 Exercise performed at higher intensities is seen to be impaired with performance decrements. 

Generally, it is recommended that fat intake range from 20% to 35% of total calories. Less than 20% does not benefit performance and could be detrimental to health. Diets that are too high in fat can lead to undesired weight gain and are not recommended for athletes. 10% or less should come from saturated sources. Endurance and strength athletes will need to adjust their fat intake accordingly, depending on their carbohydrate and protein needs. 

Since fat takes longer to digest, athletes should moderate their fat intake prior to activity to avoid stomach upset. Athletes are encouraged to incorporate the majority of their fat into pre-workout meals when they have 3 to 4 hours before being active. Post-workout fat intake can be more flexible as long as it doesn’t interfere with carbohydrates and protein needs. 

General guidelines for fat intake include the following: 

  • Fat is a highly efficient energy source used almost exclusively at various levels of exercise 
  • Building blocks of fats are fatty acids 
  • Sources include nuts, seeds, peanut butter, dairy, fish, egg yolks and 
  • Fat intake should be 20 to 35% of total calorie intake with 10% or less coming from saturated fats 
  • The lower limit of intake should not go below 10% of the total kcal profile 
  • Dietary strategies of intake affect moderate activity differently than higher intensity levels 

A Word on Alcohol 

Alcohol is not a macronutrient or micronutrient. It has no nutritional value and the calories that come from consuming alcohol are sometimes referred to as “empty calories” since no energy is derived from its metabolism. In general, successful high-functioning athletes are typically not heavy drinkers but in terms of physiology, we have to understand the effects of alcohol on our client’s nutrition profile. This is mainly due to how alcohol suppresses lipid oxidation, increases unplanned food consumption (kcal totals), and when excessive, can be an obstacle to the achievement of body composition goals 

The direct negative effects of alcohol on exercise metabolism, thermoregulation, and skills/concentration are well documented. The effects of alcohol on strength and performance can remain for several hours even after signs and symptoms of intoxication have faded. In the post-exercise phase, alcohol in-take may interfere with recovery by impairing glycogen storage, impairing re-hydration (due to its suppression of antidiuretic hormone) and impairing MPS. 

To Supplement or Not to Supplement? The Micronutrients 

Athletes frequently restrict energy intake, especially those in sports where one has to “make weight” to stay within a certain group of competitors (football, for example). But when our athlete starts to rely on extreme weight-loss practices, eliminates one or more food groups from their diet, or consumes poorly chosen diets, they may consume sub-optimal amounts of micronutrients and therefore benefit from micronutrient supplementation. This is a fairly common occurrence, seen most frequently in the case of iron, vitamin D, calcium and some antioxidants. 


Anemia, is a very serious and common state for athletes, as it can impair muscle function and limit work capacity in your athlete. Furthermore, some athletes involved with intense training in a hot climate may also have increased iron losses in sweat, urine, feces, and intravascular hemolysis. The iron requirements for all female athletes may be increased by up to 70% of the estimated average requirement. 

When supplementing, consider that the intake of iron supplements in the period immediately after strenuous exercise is contraindicated since there is the potential for elevated hepcidin levels to interfere with iron absorption. 

Reversing Iron-Deficient Anemia (IDA) can require up to 6 months. Therefore, if recognized early on, the client can benefit from nutrition plans that prevent a deficiency before IDA develops. Athletes who are concerned about iron status or have iron deficiency without anemia (e.g., low ferritin levels without IDA) should be encouraged to adopt eating strategies that promote an increased intake of food sources of well-absorbed iron (e.g., heme iron, non-heme iron and vitamin C foods). 

Vitamin D 

Vitamin D regulates calcium and phosphorus absorption and metabolism and plays a key role in maintaining bone health. There is also emerging scientific interest in the biomolecular role of vitamin D in skeletal muscle where its role in mediating muscle metabolic function may have implications for supporting athletic performance. A growing number of studies have documented the relationship between vitamin D status and injury prevention, rehabilitation, improved neuromuscular function, increased type II muscle fiber size, reduced inflammation, decreased risk of a stress fracture, and acute respiratory illness. 


Calcium is especially important for the growth, maintenance, and repair of bone tissue; regulation of muscle contraction; nerve conduction; and normal blood clotting. Low calcium intake is associated with restricted energy intake, disordered eating, and/or the specific avoidance of dairy products or other calcium-rich foods. Calcium supplementation should be determined after a thorough assessment of the usual dietary intake. 


Antioxidant nutrients play important roles in protecting cell membranes from oxidative damage. Because exercise can increase oxygen consumption by 10- to 15-fold, it has been hypothesized that chronic training contributes a constant ‘‘oxidative stress’’ on cells. Acute exercise is known to increase levels of lipid peroxide by-products but also results in a net increase in native anti-oxidant system functions and reduced lipid peroxidation. Thus, a well-trained athlete may have a more developed endogenous antioxidant system than a less-active individual and may not benefit from antioxidant supplementation. There is a fair amount of research indicating that antioxidant supplementation may negatively influence training adaptations.