Many athletes actively seek changes in body weight in hopes of improving athletic performance. In some sports, such as wrestling, gymnastics, dancing, and running, some athletes and coaches may associate optimal performance with a relatively low body mass. In other sports, particularly contact and collision sports, such as football, increased body mass is often encouraged. Athletes interested in losing or gaining weight should discuss strategies for healthy weight loss or weight gain with their doctor.

Here is information from the American Academy of Pediatrics about healthy weight loss or weight gain for young athletes.

Weight and Age

Ages 2 to 10 Years

Concerns about weight in this age group should be addressed with the child’s doctor. These discussions should focus on growing healthy bodies rather than achieving a specific weight and include education for families on fostering healthy lifestyle habits. Children in this age range with a body mass index (BMI) that is greater than the 99th percentile may be encouraged to maintain or gradually decrease their weight under close supervision of their doctor.

Ages 10 to 12 Years

Some children in this age group will start to grow faster as they enter puberty. The “early bloomers” often have a temporary size and strength advantage over children who develop later. Boys who have not yet begun puberty will sometimes try to gain weight to keep up with their peers. However, efforts to gain weight before puberty lead to increased fat, not muscle, and do not speed up strength and muscle development.

Ages 12 to 18 Years

Adolescents spend more time outside their home and have increasing responsibility when it comes to food choices. Many teens try hard to gain or lose weight to improve how they look. It is vital for families and doctors to be sensitive to adolescents’ concerns about body image and weight and approach these discussions in a thoughtful way. In addition to screening for obesity, doctors should evaluate teens for unhealthy weight control practices such as dieting, calorie restriction, binge eating, purging, and laxative use. If an adolescent does fall into the obese category (BMI > 95th percentile), the doctor may encourage weight maintenance or a slow reduction in weight, as long as the adolescent is able to maintain healthy eating and physical activity habits. Teen athletes may also think about changing their weight to improve their sports performance. Regardless of an adolescent’s reason for weight change, it is important to emphasize that everyone’s body is unique and the end goal is overall fitness and health.

Weight and Sports Performance

Athletes who are trying to improve sports performance should keep the following in mind:

• There is no single “best” weight for a given sport. For each athlete there is a range of healthy weights that allow for peak athletic performance.
• It is often more beneficial to monitor athletic performance (such as strength, speed, jump height) than weight.
• Weight and BMI are not good indicators of body fat and lean muscle. Athletes who are thinking about making major changes in their weight, and those who are in weight-classified sports (such as wrestling), should have body composition measurements taken to find out their percentages of body fat and lean tissue to help guide recommendations for more realistic and safer weight goals.
• Coaches and parents often do not realize the influence they have on young athletes. Even a casual weight-related comment from a coach might place athletes at increased risk for unhealthy eating behaviors. Parents should try to be aware of weight-related messages their children may be receiving from coaches.

Weight Loss

Athletes (and coaches) in many sports, such as wrestling, gymnastics, dancing, and running, believe they will perform better if they lose weight. For athletes who are above their healthy weight, losing excess body fat may be beneficial. However, weight loss in athletes who are already at a healthy weight is not likely to improve performance.

Athletes who routinely expend more energy in training or competition than they take in nutritionally may develop relative energy deficiency in sport (RED-S). This syndrome can cause disruptions in the body’s hormonal, endocrine, and physiologic functions in men and women alike. Poor bone health and menstrual irregularities in women are the most common complications. If you are concerned that an athlete may be experiencing RED-S, it is important the athlete be evaluated by a doctor and sports dietitian who are experienced in treating this disorder.

Healthy Weight Loss Tips

For the athlete who wants to lose weight in a healthy way, the following tips may be helpful:

• Do not lose more than 1 to 2 pounds per week. Anything faster than this is often due to loss of muscle tissue or water (both of which are important for athletic performance).
• Weight loss efforts should combine changes in athletic training and diet. When making changes in training, it is important that athletes do not increase their training load or volume too quickly, which could place them at risk of an overuse injury. Changes in nutrition should be discussed first with a doctor or dietitian and should be aimed at ensuring athletes are appropriately fueling their body to meet the demands of their training.
• Cycles of weight loss and gain should be avoided. This leads to decreases in metabolism and calorie requirements.
• Weight loss can be difficult and frustrating. Young athletes who wish to lose a lot of weight should talk with their doctor first.

Weight Gain

Athletes in some sports, such as weight lifting and football, think their strength, power, and sports performance will get better if they are able to gain weight. However, it is important to remember that weight gain can come from increases in either fat or muscle. Increases in muscle may be very helpful for some young athletes, but increases in fat may result in decreased sports performance. Unfortunately, it is much easier to gain fat than muscle. Young athletes should be encouraged to make changes that will help with improving strength, rather than just gaining weight.

Healthy Weight Gain Tips

For athletes who want to gain lean muscle in a healthy way, the following tips may be helpful:

• Gain only 1 to 2 pounds each week. Gains faster than this often lead to greater increases in fat.
• Increase calories by 300 to 400 calories each day. Increasing intake of higher-calorie yet nutrient-rich foods, such as nut butters, avocado, and healthy oils (such as olive oil), is a good way to increase calories. Two servings of instant breakfast or meal replacement products is another option. (Note: “weight gainer” supplements often contain too many calories and cause greater increases in fat than in muscle.)
• Eat every 2 to 3 hours, or about 5 to 9 times per day.
• Weight lifting should be done in sets of 8 to 15 repetitions for muscle growth, or in sets of 4 to 6 repetitions to develop strength and power.
• There should be at least 48 hours between hard workouts. This allows muscles to recover between training sessions.
• Increases in weight and muscle size tend to become much easier during puberty.

Remember

Athletes should always check with their doctor first before making any changes to their diet to lose or gain weight.

Visit www.HealthyChildren.org for more information.

Disclaimer

The information contained in this publication should not be used as a substitute for the medical care and advice of your pediatrician. There may be variations in treatment that your pediatrician may recommend based on individual facts and circumstances. Original resource included as part of Care of the Young Athlete, 2nd Edition.

© 2021 American Academy of Pediatrics. All rights reserved.

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