Optimizing You: Everyday Athletes’ Guide to Body Composition and Peak Performance. Part 1

Over the last ten years, there has been tremendous growth in research papers, professional consensus, and educational possibilities in sports nutrition. This discipline has shown to be a vibrant junction of science and application, offering athletes sophisticated and evidence-based instructions. The necessity for personalized and periodized nutrition plans that correspond with the athletes’ training cycles, particular demands of their sports, and overall health goals is one of the key themes in contemporary sports nutrition. Nutrition strategies must adjust to the rigors of an athlete’s training program, which can range from light to strenuous. These programs should be adjusted not only to the sort of training but also to the specific event, performance objectives, and personal preferences of the athlete. Training focuses on improving metabolic efficiency and flexibility, whereas competition nutrition focuses on maintaining adequate energy stores and cognitive function.

Energy availability is critical to both athlete health and the effectiveness of nutrition strategies. It is critical for balancing the energy consumed and the energy expended during training. Optimal body composition is a nuanced goal that is critical for peak performance but requires careful management to protect long-term health and avoid undue stress.

Training-nutrition interactions are critical for promoting functional and metabolic adaptations. While proactive nutrition support is necessary for peak performance, some training adaptations may occur even in the absence of such assistance. Energy, carbohydrate, and protein recommendations are increasingly scaled to an athlete’s body mass to accommodate a wide range of body sizes and to emphasize the importance of nutrient timing.

Athletes must balance training intensity for maximum gains with the risk of illness or injury from overtraining. Nutrition strategies for competition should be tailored to reduce fatigue by taking into account the specific event, environmental conditions, and individual athlete needs.
Performance nutrition breakthroughs show that even the sensation of nutrients in the oral cavity can positively influence performance, implying new strategies for short-duration events where metabolic benefits were previously overlooked.

Finally, because supplements and sports foods are popular among athletes, a practical and critical approach is required. Athletes should be encouraged to weigh the potential benefits against the costs and to understand that supplements are most beneficial when used in conjunction with a well-planned nutrition plan.

Energy Requirements, Energy Balance, and Energy Availability: Foundations of Athletic Performance

Energy intake is important for athletes to understand and manage because it affects overall health, nutrient intake capacity, and body composition. Despite the common issue of under-reporting, athletes typically calculate their energy intake using methods such as food records, 24-hour recalls, or food frequency questionnaires. Proper training in reporting intake can improve the accuracy of this data.

Athlete energy requirements do not remain constant; they vary with the periodized cycles of training and competition. Environmental stresses and physiological changes, for example, can both increase these energy requirements. Aging and certain phases of the menstrual cycle, on the other hand, may lower them. When energy intake equals total energy expenditure (TEE), which is a combination of basal metabolic rate (BMR), thermic effect of food (TEF), and thermic effect of activity (TEA), energy balance is achieved.

Estimating TEE can be difficult for athletes, especially elite athletes. While BMR is ideal, resting metabolic rate (RMR) is a more practical metric, though it is typically 10% higher. TEE is estimated using predictive equations such as Cunningham or Harris-Benedict, which are adjusted with activity factors. However, these may not account for the high TEA of endurance athletes, who can expend up to 50% of TEE through activity.

Energy availability (EA) is a relatively new concept that focuses on the energy available to the body after accounting for exercise expenditure. It is especially important for health and function, with 45 kcal/kg FFM/d being considered adequate. Low EA, especially below 30 kcal/kg FFM/d, can disrupt a variety of bodily functions and is frequently associated with disordered eating or inadvertent under-fueling during intense training or competition phases.

An example of EA calculation demonstrates how this concept can be used to plan dietary intake. EA was inspired by research on the Female Athlete Triad, which highlighted the interconnected issues of eating disorders, menstrual dysfunction, and bone density. This has evolved into the broader concept of Relative Energy Deficiency in Sport (RED-S), which recognizes a range of potential health consequences for both male and female athletes who do not meet their energy needs after adjusting for exercise expenditure. RED-S has a wide range of effects, affecting many physiological systems and performance factors.

Understanding that health impairments can occur along a spectrum of decreased EA necessitates additional research into specific thresholds. Importantly, a low EA does not always imply weight loss or a negative energy balance; it can also result in a lower RMR and a new, unhealthy steady state.

The importance of assessment tools such as the Eating Disorder Inventory-3 or DSM-5 criteria is emphasized in screening and treatment guidelines for low EA. Interventions to improve EA, fortunately, have been successful in reversing some health impairments. For example, increasing EA to around 40 kcal/kg FFM/d helped female athletes resume normal menstrual functions within a few months. This emphasizes the importance of properly managed energy intake and availability in supporting athletes’ health and performance.

Body Composition and Sports Performance: A Balanced Perspective

Body composition, which includes characteristics such as body size, shape, and the relative amount of fat-free mass, is an important aspect of an athlete’s physique that can be altered to potentially improve performance in a variety of sports. While body mass and composition are modifiable, they do not predict success in isolation, and there is no one-size-fits-all “optimal” composition for athletes.

Athletes in strength and power sports may concentrate on muscle hypertrophy to increase fat-free mass during specific training cycles. However, in disciplines where athletes are classified by weight or where power-to-weight ratios must be optimized, such as combat sports or rowing, the goal shifts to maximizing lean mass within a weight class. Endurance athletes, such as runners and cyclists, may aim for a lower body mass for efficiency and cooling benefits. Athletes in team sports, acrobats, and dancers may prioritize leanness for speed, agility, and performance quality. Aesthetics are also important in sports such as bodybuilding, diving, and dance.

The pursuit of low weight or body fat targets, on the other hand, can lead athletes to harmful weight control practices, such as disordered eating and insufficient energy and nutrient intake. Such behaviors not only endanger one’s health but can also impair one’s performance. The ideal approach is a gradual, periodized strategy towards an individual’s “optimal” body composition that takes into account the athlete’s health and performance throughout their career, avoiding extremes such as excessive weight gain during low training periods or unhealthily low body fat levels.

Sports dietitians play an important role in guiding athletes to achieve a healthy body composition without jeopardizing their nutritional status or succumbing to pressures to achieve a specific physique. They also monitor sports that reward larger body mass to detect potential metabolic risks. Finally, the emphasis should be on a well-balanced and customized composition that supports the athlete’s well-being and competitive goals.

Body Composition Assessment in Athletes: Methods and Considerations

Athletes’ body composition is measured using a variety of techniques, the most common of which are DXA, hydrodensitometry, air displacement plethysmography (like BodPod), skinfold measurements, and bioelectrical impedance analysis. DXA is accurate, but it has disadvantages such as cost, accessibility, and radiation exposure. Skinfold measurements, while less accurate, are widely used because they are inexpensive and convenient.
To ensure reliability, all methods require standardized protocols and calibrated equipment. To avoid skewing results, athletes must follow specific pre-assessment guidelines, such as maintaining consistent training, fasting, and hydration levels.

Rather than setting fixed body composition goals, it is recommended to work within ranges that account for seasonal and career variability. To avoid encouraging unhealthy body image obsessions, results must be communicated sensitively.
Sports dietitians play an important role in guiding athletes towards healthy body composition practices, advocating for long-term, safe strategies, and assisting in the modification of rules that may pressure athletes into risky weight loss behaviors. They also work on early detection and intervention for disordered eating in athletes.

Altering Body Composition and Weight in Athletes: Guidelines and Strategies

Athletes frequently require assistance in establishing realistic body composition goals. Understanding nutritional strategies for effectively increasing muscle mass or decreasing fat, and incorporating these into a balanced eating plan without resorting to extreme or fad dieting practices, is part of this. Follow-up is essential for athletes to stay on track and avoid unhealthy behaviors.
Athletes in weight-sensitive sports may use rapid weight loss methods to compete in lower weight categories, according to evidence, but these practices can result in dehydration, muscle loss, and other health problems. Short-term weight loss is preferable to long-term energy restriction when necessary, with an emphasis on methods that preserve muscle mass and health.

A small energy deficit and increased protein intake are important to weight loss strategies, with a weekly weight loss of less than 1%. Personalized diet and exercise plans should take into account the athlete’s goals, training, previous experiences, and successful trials.
Most athletes can achieve short-term body composition goals by reducing daily calorie intake by 250–500 calories while maintaining or increasing physical activity. Timing and meal composition can also play an important role in supporting training and recovery and, as a result, optimizing body composition.

However, athletes face barriers such as limited access to healthy food, food preparation skills, daily routine, and the temptation of energy-dense foods, which can derail their nutrition goals and lead to the pursuit of quick, unhealthy weight loss solutions, especially when traveling or living communally.
According to research (Evidence Analysis Library Questions 1 & 2), negative energy balance has a mixed effect on sports performance, indicating the complexities of factors such as diet quality, carbohydrate availability, excessive training, and dehydration. While research is limited, there is some evidence that higher protein intake during energy deficits may be beneficial.

Read more — Nutrition and Athletic Performance. Medicine & Science in Sports & Exercise 48(3):p 543–568, March 2016. | DOI: 10.1249/MSS.0000000000000852