Determine an Athlete's Optimum Sport Weight in 4 Steps

STACK Expert Any Jamieson-Petonic explains how to create a diet plan to help athletes achieve optimum weight for their sport.

After attending the 2015 Academy of Nutrition and Dietetics Annual Conference in Nashville, I came away with some awesome tips on how you can help athletes meet their weight and performance goals. Two of the speakers, Marie Dunford, PhD, RD, and Michele Macedonio, MS, RDN, CSSD, provided four exceptional strategies that are perfect for athletes.


As a sports dietitian, I make sure to gain a good understanding an athlete's individual nutritional needs before I provide an accurate assessment. This provides insights into the things dietitians look for, and it can help you make intelligent diet decisions for your athletes.

Sport-Related Characteristics

Sport-Related Characteristics

  • Sport and position of each player. Does the athlete have a need for physical uniformity to be matched against an opponent, as in soccer, or is there a different need based on position? Think of a cornerback versus an offensive lineman in football.
  • Need for power and endurance. Athletes requiring explosive power, such as powerlifters, need more skeletal mass and higher body weight than long-distance runners.
  • Power-to-weight ratio. To produce power, many athletes need adequate skeletal muscle mass but a relatively low percentage of body fat. Excess body fat is considered dead weight and doesn't contribute to strength. For example, your strength-to-body weight ratio can affect your speed. If you maintain your strength and lose weight, you will ultimately run faster.
  • Relative need for speed, flexibility and agility. Too much skeletal muscle mass can affect all three. Consider a baseball player who gains an enormous amount of mass but reduces his flexibility to the point where he cannot swing the bat or throw a ball with proper mechanics.
  • Weight certification requirements. Some sports, such as boxing and wrestling, require specific weight certifications to be eligible to compete.

Physique-Related Characteristics

Physique-Related Characteristics

  • Body weight. Athletes should strive to maintain a weight range. Body weight changes daily, and fluid shifts can cause up to 5-pound differences at any time during the day. Weight ranges allow the athlete to set an achievable goal that is realistic and appropriate.
  • Body Composition. On its own, it does not predict success in sports, but it does play a role in performance.
  • Body build. There are three body types—ectomorph, mesomorph and endomorph. Ectomorphs are hard gainers and naturally thin. Mesomoprhs have athletic builds and hourglass frames; they gain muscle and lose fat easily. Endomoprhs have broad hips and gain muscle easily. Think shot-putters.
  • Body Appearance. Some sports (e.g., gymnastics, figure skating, dance, beach volleyball) may cause athletes to be dissatisfied with the way they look.

Estimate of Nutritional Needs

Estimate of Nutritional Needs

Based on the information we have collected, we can now determine the nutrition needs of an athlete. First and foremost, we need to look at his or her current diet to see where we might be able to improve things. Drastic changes don't often last, so it's important to work with the athlete to find out what he or she likes and dislikes.

Also, it's important to get an estimate of the athlete's resting metabolic rate so we know how much minimum energy he or she needs on a daily basis. The best way to do this is with a Bodpod or metabolic cart, but they aren't available to everyone. You can estimate it with the equation presented in this article.

Energy intake is underreported by 10 to 20 percent by high performance athletes, and often overestimated by recreational athletes.

Once nutritional needs are determined, the next step is goal setting.

Goal Setting

Goal Setting

These include Target Minimum Weight, Target Desired Weight, and Realistic Weight Range. Target Minimum Weight is determined by using Fat Free Mass and dividing by the difference of 1 minus the % of desired body fat.

Target Desired Weight is current Fat Free Mass divided by [1 minus minimum body fat]. Realistic Weight Range is between Target Minimum Weight and Target Desired Weight, plus or minus 1 or 2 pounds. These numbers are affected by sport, position and realistic expectations for the athlete.

Create an Action Plan

Determine an Athlete's Optimum Sport Weight in 4 Steps

Here's where the rubber meets the road—determining actual nutrient amounts and timing. A solid nutritional base includes the right distribution of carbohydrates, protein and fat:

  • Carbohydrates: 5-12 grams per kilogram (kg) of body weight
  • Protein: 1-2 grams per kg of body weight
  • Fat: No less than 1 gram per kg of body weight

(For reference: 1 kilogram is equal to 2.2 pounds, so a 180-pound athlete weighs 82 kilograms.)

If the objective is to add muscle or mass, the athlete's goals should depend on whether he or she has been resistance training, and the duration and intensity of the exercise.

  • Males: To gain 0.5-1.0 pound of lean mass per week, consume an additional 400-500 kcals per day.
  • Females: the goal should be to gain 0.25-0.75 pounds per week.

Both pre- and post-exercise nutrition are critical for successfully gaining lean muscle mass.

Pre-Exercise Fuel: Examples include a slice or two of wheat bread with 1 tablespoon of peanut butter and 12-20 ounces of a sports drink—or a protein bar and 12-20 ounces of a sports drink.

Post-exercise requires carbohydrate and protein, with 6-12 grams of essential amino acid (approximately 10-20 grams of high quality protein). Good examples include 8 ounces of fat-free Greek yogurt plus 1/2 cup of low-fat granola plus 2 tablespoons of dried blueberries and a sports drink—or a 16-ounce post-recovery beverage with 15-20 grams of protein.

If the objective is to reduce body fat, it's important to create an energy deficit with minimal loss of lean tissue. A moderate caloric restriction would include a minimum of 30 kcal's per kg of body weight and at least 1.8-2.7 grams of protein per kg of body weight to help preserve lean body mass and satiety.

The timing of body composition goals is also important

Pre-season: This is the best time to do a complete nutritional assessment and evaluation of the needs and performance goals of your athletes. Whether the goal is to lose body fat or gain skeletal mass, this is the time to do it.

Late Pre-season: Re-assess and tweak your performance plan.

Competitive Season: Adjust for in-season demands and challenges.

Evaluation and Re-Assessment

With specific goals and action plans established, make sure the plan still meets the athlete's nutritional needs and remains appropriate for his or her current physical activity.

Areas to consider include:

  1. Monitor weight, body composition and girth measurements once a week
  2. Evaluate the current dietary plan and look for areas of improvement
  3. Modify, or redesign the meal plan as needed.

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