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Assessing Energy Requirements, Energy Balance and Energy Availability 

Assessing Energy Requirements, Energy Balance and Energy Availability 


When we work with an athlete or player client, we quickly learn that the needs of this special group are hardly static. Their needs change daily, even throughout the day. This is a group that includes those who are managing nutrition intake within very strict parameters and guidelines to match the goals they want to conquer. It could be a practice session later that day, a refueling for a mid-afternoon workout or a track and field event on a weekend day. How this group train is typically periodized. 

Let us begin with a few safe assumptions. 

  1. Energy balance occurs when total Energy Intake (EI) equals Total Energy Expenditure (TEE). 
  2. This consists of the total sum of the basal metabolic rate (BMR), the Thermic Effect of Food (TEF), and the Thermic Effect of Activity (TEA) 
  3. 3. To determine energy requirements we have to consider each of these: The TEE, BMR, TEF, and TEA 

It’s pretty handy to have all of this summarized but the challenge is not completely resolved yet. We still have to learn how we get these values. 

Consider BMR, for example… 

When your typical client is a highly trained, competitive athlete, the need to get BMR measured accurately is vital. Without an accurate reading of this metric, other formulas based on BMR, become less accurate. But there is controversy, as always, within the fitness community. After decades of learning and studying research, there is general agreement to assess this value from a resting perspective, so RMR is often assessed as well, as it can be up to 10% higher than BMR. Its use is based on the belief that it allows for some individual evaluation of certain factors beyond a rested state. 

Basal Metabolic Rate (BMR) Versus Resting Metabolic Rate (RMR)

BMR estimates can be done using either the Cunningham or the Harris-Benedict equations, as these include an appropriate ‘activity multiplier’ to estimate TEE (Harris-Benedict) and BF% (Cunningham). Since any one formula will not work with every athlete, using both might increase accuracy. 

Differences in percent values need to be understood, as they help further define our client’s information with greater accuracy. If we consider sedentary individuals, the RMR may be as much as 60-80% of their TEE; for elite/ highly trained and conditioned athletes, the RMR can be as little as 38-47% of their TEE1. This elite group would also have a relatively high TEA, at nearly 50% of their Total Energy Expenditure (TEE). 

In consideration of the constant evolution of nutrition science, a newer concept of assessing EA (Energy Availability) has become more popular. This method equates that energy intake is based on optimal health and function (i.e. performance) as opposed to energy balance being the goal. Using EA represents a different approach to the assessment of this important information. If it becomes widely accepted and passes the test of validity, it could easily become standard practice in our field. 

Calculating Energy Availability

Calculating Energy Availiability includes a calculation of exercise energy expenditure, subtracted from dietary intake and normalized for fat-free mass (FFM). This then represents the amount of energy available for the body to use for all functions apart from exercise or PA. The energy cost of exercise is subtracted in this equation. 

Originating from a movement to protect female athletes from falling prey to the Female Athlete Triad, the Energy Availability equation, and methodology was first studied among female participants. While recognizing the interrelated nature of dis- ordered eating, low bone mineral density and menstrual dysfunction, a more complete picture emerged with unintended consequences being revealed, including other physiological factors co-creating the complexities of the Triad. 

There are some caveats to using this method, however; the accuracy and reliability of BF testing is one factor; a low EA could also be a common problem, especially when calories are being managed in the direction of reductions (i.e. a deficit); a low EI or a high TEE is also possible in this scenario of assessment. When one factor in how all of these variables mix to shape our unique athlete’s needs, we can see the need to be as accurate and diligent with our information gathering. 

In nearly every competitive sport, maintaining proper body weight (BW) is critical to performance. Again, body composition, specifically, is a common variable you will address with both nutrition strategies and the coaching plans to support client goals. It is now understood however that reductions in EA, which often occur with attempted weight loss, impair health and function. Note, low EA is not synonymous with negative EB or weight loss. That said, if a reduction in EA is associated with a reduction in RMR, metabolism is slowed, producing a new, lower steady state of EB. 

Why is Energy Availability Important?

The energy goal for an athlete is to be able to adjust his/ her dietary intake to cover all the expenditures from exercise and training. This has to promote an energy balance that is positive for health and performance. Athletes sometimes can negatively alter their EA knowingly or unknowingly as it can be reduced by increasing training, over-exercising, or decreasing the amount of food one eats. Some athletes adopt abnormal eating behaviors such as fasting, skipping meals, restricting foods, binge eating, or using diet pills or laxatives. Other athletes also have eating disorders. Whatever the case, these scenarios can result in low EA. Low EA results in physiological changes that cause hormonal, metabolic and functional disruptions This energy deficiency affects physiological functions such as metabolic rate, bone health, immunity, protein synthesis, cardiovascular and psychological health, and menstrual function. This can result in fatigue and impair the ability of muscles to use oxygen. 

Understanding Energy Availability is important as it is now widely accepted that low EA levels create performance decrements in both male and female athletes. When EA is low for reasons that are not understood, you should explore more about the client, as disordered eating and eating disorders are both scenarios where clinical intervention is required. This is very serious in nature, so it is important to understand the condition in its entirety. 

How Can You Learn More?

The NESTA Sports Nutrition Specialist course is designed for personal fitness trainers, strength coaches and nutrition experts who want to learn cutting-edge techniques for increasing sports performance, reducing recovery time, and enhancing the overall well-being of your clients and athletes.

If you want to help clients with food, diet, weight management and improving the results of their fitness routines, the Fitness Nutrition Coach course is for you. You will learn about optimal nutrition, including proven techniques for increasing energy, optimal health and decreased dependence on medications. Instantly increase your job and career opportunities with this popular professional credential.

You can become a Certified Personal Fitness Chef and expand your current personal chef business, or add a new profit center for your fitness or wellness business. Many personal chefs cook and coach people in groups to help more people and earn more money per hour. Some chefs provide weekly meal prep service for health-minded customers and athletes.

Check out what it takes to start a career in personal fitness training. This is your most affordable and fastest way to become a highly qualified personal trainer.

NESTA coaching programs are open to anyone with a desire to learn and help others. There are no prerequisites.

That’s it for now.

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