Should You be Setting a Body Fat Goal?
“What should my goal weight be?”
“What body fat percentage should I be?”
The issue with these questions from athletes is that, frankly, I don’t have a magical answer.
Dietitians like hard numbers and data. We’re trained to be experts by basing our answers off of research studies (a great thing!). Yet solely looking at a body composition table from a research paper to recommend an athlete’s goal weight, fat mass, or fat-free mass isn’t helpful.
Let’s discuss why.
Why set goals for Body Weight and Composition?
When evaluating nutritional intake or body composition (i.e., body fat and muscle), dietitians need something to compare the athlete’s status quo with. That’s how goals can be set.
As a nutrition example, the recommended dietary allowance for calcium for adults aged 19-50 years is 1,000 milligrams (mg). If an athlete consistently reports only consuming 600 mg calcium, dietitians increase awareness to include foods, beverages, and/or dietary supplements to help an athlete consistently consume an additional 400 mg calcium per day. We select a benchmark, compare, and apply a goal.
The same goes for weight and composition goals: What should the athlete be aiming for?
Flat out, there are no review papers* showing that a certain body weight or fat percentage leads to performance success in X sport, X event, or X position. When setting nutrition goals, there is evidence that a chronic deficiency in Y nutrient leads to Z concern. This is why benchmarking nutrition can be helpful. When it comes to body weights and composition in regards to performance (read: NOT the importance of what an athlete looks like), this data simply does not exist.
*A review paper considers the breadth of evidence on a research topic and compiles the evidence. If pooling together ALL of the results, what are we left with? Review papers, when done well, help connect smaller studies to form a larger pool of data.
What is a Body Composition Table?
Here’s a link to a research paper regarding what I mean by these tables, plus one from the linked paper that lists anthropometric data and body composition as skin folds.
The Potential Issues with Using Body Composition Tables
Who is Being Measured and When?
Tables may show the range of body fat for an entire football or track and field team. For the former, an offensive lineman tends to have a higher body fat percentage than a running back. For the latter, a distance runner will have a lower body weight than a sprinter or thrower. Basing athlete goals off of a large range isn’t helpful.
But what about tables meant for all adults, both athletes and regular humans? The body fat percentage recommendations produced by a Bod Pod include multiple ranges within its print out. The “Ultra Lean” category is designated as “fat levels often found in elite athletes”. In reality, “elite” is a broad set of numbers meant to cover all sports, positions, and events, yet the Bod Pod attempts to narrow its focus as a one-size-fits-all category.
Beyond the athlete versus regular human debate, what sex and age group(s) are being measured? Is the athlete at the collegiate or professional level? How long have they been at their elite status for? What year in college are they (e.g., freshmen athletes without a history of a well-designed weight lifting program typically have a lower muscle mass than a senior)?
Often, numbers reported within the research are cross-sectional (meaning athletes were tested once and included in the data set). Yet anyone working with athletes knows that their body weight and composition changes throughout the year. For instance:
The offseason: Depending on the sport, an increase in fat mass and decrease in muscle may occur as training and competition winds down. This effect may be the opposite, as athletes have more time to train and at a higher intensity. For a baseball player in-season who is playing every day, muscle soreness isn’t ideal. For them, training harder in the offseason tends to result in improved body composition.
The preseason: May focus on body recomposition, as fat mass levels begin to decline with increased conditioning or simply a return to a structured training regimen.
During the season: I’ve seen athletes maintain their weight, lose weight, lose muscle, and/or gain fat. As always, it depends on the athlete, sport, position, and their goals.
Taking this a step further, let’s say body composition is measured three times annually:
At the time of reporting to their team (i.e., beginning of pre-season training).
At the end of pre-season training before heading into their season.
At the end of the season.
All three of these measurements are expected to be different numbers. Unfortunately, body composition tables don’t specify when during the year or season data was collected. Using a table to “compare” the athlete sitting in front of you to provides practitioners with the same range of numbers to use all year round. Yes, if the range of body fat percentage for a sport and position/event were 12-18%, a practitioner could use the above logic to guide an athlete throughout that range given the time of year.
How Healthy were Those Being Measured?
Another issue is the lack of context surrounding those numbers: How healthy was the athlete at the time of measurement?
It’s not uncommon for athletes to have improper fueling strategies, body image concerns, disordered eating tendencies, or even eating disorders. It's common for athletes, like distance runners, to strive for a lower body fat percentage as an important race nears. All of these factors can influence body weight and composition, but those stories aren’t told alongside body composition tables. Are we then recommending an athlete should have X percent body fat when the data from their sport and position was based on data sets including athletes suffering from relative energy deficiency in sport? Not menstruating? One skipping breakfast as avoid weight gain? One with a history of recurrent infections and/or injuries? Or an athlete at their peak, lowest body fat percentage or the year?
Always think: What is the potential long-term impact of our recommendations as practitioners? Is there a blind spot in the research? If you aren’t confident in the research, acknowledge that.
Use the Science as a Guide, but Apply your and the Athlete’s Expertise when Setting Goals
Despite the current trend of NOT focusing on weight and body fat percentage goals, many athletes still request this information and it’s the job of a qualified sports dietitian to carefully guide the athlete. That said, make sure the data you’re making your recommendations from is used as a starting point—one that takes into consideration other data points that include the experience the athlete has within their own body.
When I meet with an athlete for the first time, let’s say there’s no historical data to evaluate weight trends or provide a goal weight. In those scenarios, here’s what I do before ever talking goal weights:
Evaluate their diet via a 24-hour recall or a typical day of fueling: Does it seem adequate? Are there excessive restrictions in the absence of medically-diagnosed food allergies or conditions?
Evaluate injury history: Including repetitive injuries and stress fractures that may signal chronic low energy availability.
Evaluate immune history: Do they have reoccurring infections and sickness that may signal chronic low energy availability?
Evaluate their weight history: Including reasons for any unintentional or intentional weight changes and their goal weight. For instance, why is it this number, who set this goal, and has the athlete ever safely been this goal weight before?
What training weight has felt comfortable for this athlete? What competition or in-season weight? Granted, learning what age they felt their “best” may still not be best, given an 18-year old may report their “best” was as a high school sophomore or the weight they were recruited at for a university team. As the practitioner, use your knowledge of growth curves and expected trends with increasing age.
Evaluate additional red flags: This includes a history or presence of disordered eating, eating disorders, and body dysmorphia.
For women: Evaluate the age when they had their first period, how often they currently menstruate, and if they utilize birth control pills or other hormones.
If multiple red flags are present, I share that concern with the athlete and a weight goal isn't the immediate plan. Rather, I want to help the athlete through their underlying issues first. It’s not always appropriate to provide a weight goal even if that was the point of the meeting and/or a coach asked you to.
If you have multiple body weight and/or composition data points, and given all of the above factors have been addressed:
Normalize fluctuations in body weight, fat mass, and fat-free mass (or lean body mass, if available) throughout the year. For a distance runner, the goal is to avoid a low body fat level all year long. They may be able to sit lighter when they need their performance to peak.
Have the athlete reflect on when they felt their strongest, most powerful, and/or fastest.
Knowing the concerns with body composition tables, potentially plug in the athlete’s experiences with those numbers. Does the athlete’s “best” align with ranges from these tables? In my opinion, who cares—especially since the goal of athlete health and wellness is to be individualized. At that point, it doesn’t matter if they’re within the average range or are an outlier. It’s fine to discuss this with athlete as to remove the stress of not fitting in within some range.
So long as the athlete’s fueling is adequate and there are no red flags, use the athlete’s expertise on their body as the guide in setting goals. Having the athlete reflect on what feels good versus what the scale reads is helpful. Personally, I don’t use tables as a guide. I want to hear how the athlete experiences their body—the subjective experience that isn’t commonly measured in research.
What are the Next Steps as Sport Medicine Departments?
When collecting team or departmental body weight and composition data, I think there should be a space to flag an athlete’s concerning efforts that they used to reach their current weight or composition (e.g., no menstruation x 4 months, weight at the time of a stress fracture, bingeing). That way, these numbers can be removed as outliers when creating team, event, and position trends. I've highlighted the orange cell in the below image to reflect that.
Use the first few body weight or composition measurements as data collection, and not for recommendations. After an entire season or year of measurements has been collected, that may be a better time to evaluate an athlete’s annual cycle and begin to provide recommendations and goals across the year. This can be the equivalent of nutritional benchmarking created for every athlete.
Create departmental policies regarding sharing body weights and compositions with coaches and any non-HIPAA** staff members. Their jobs are to coach skills, plays, tactics, teamwork, and leadership—not to be hampered down in body weights and fat percentages (notice how coaches rarely ask to see numbers on muscle changes, but only weight or fat?). There are multiple examples of coaches using body numbers that negatively impact an athlete’s physical, mental, and emotional health over the long-term. For instance, Nike’s impact on Mary Cain or the University of Oregon and their “nothing but numbers” approach for their track and field program (the athletic department has since changed their position on who sees these numbers, which is fabulous).
And lastly, sometimes it’s best to NOT provide an answer: Simply because an athlete asks a question, doesn’t mean they need a tight and neat response. Often, it’s best to explain context around a broad answer. This allows the athlete to think for themselves, reflect on their goals and past experience, and ultimately arrive at what works best for them. Good practitioners lead athletes to their own solution that is guided by research and experience.
**Per the CDC: “The Health Insurance Portability and Accountability Act of 1996 (HIPAA) is a federal law that required the creation of national standards to protect sensitive patient health information from being disclosed without the patient's consent or knowledge.”
