Sports Nutrition Guide for Nutrition Professionals

Sports Nutrition Guide for Nutrition Professionals

Fueling wisely for exercise and sport is essential to keep athletes performing their best. Individual nutrition strategies may vary, but generally, athletes can strive to consume energy to fuel performance, to achieve a sport-specific body composition, and to eat to limit illness and injury.

This article was written by Ashley Leone RD, MSc, CDE,
specializing in Sports Nutrition and Owner of Gazelle Nutrition Lab based in Toronto.


Energy and Macronutrients


Athletes eat to power activity and attain a body composition that benefits their performance in their chosen sport. Energy requirements are dynamic and depend on the periodized training and competition cycle.

Energy needs additionally vary depending on fat-free mass (FFM), training demands, temperature, level of stress including some injuries, altitude, possibly stage of the menstrual cycle, and some medications. To fuel appropriately, athletes need to modulate their food intake, or energy intake (EI), according to these changing needs.

Athletes benefit from a consultation with a sports dietitian to determine personal daily caloric needs depending on their weight and body composition goals. Athletes should ensure adequate Energy Availability (EA) to avoid performance impairments and reduce injury risk. EA is the amount of energy required to optimally maintain body functions, not including the energy necessary for exercise.


The macronutrients - carbohydrates, protein, and fat - each contribute energy and specific functions to an active body. Macronutrient profiles can be manipulated around exercise to achieve specific training adaptations. Any athlete wanting to try these strategies should enlist the help of a sports dietitian.

nutrients distribution in the nutrium software

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Carbohydrates are central to an athlete’s diet, particularly on intense and heavy training days. Carbohydrates improve performance by fueling high-intensity efforts, reducing perceptions of fatigue, and enhancing cognitive drive.

Daily carbohydrate goals are dependent upon the intensity and duration of exercise and can range from:

  • 3-5 g/kg of body weight on light exercise days to;
  • 8-12 g/kg of body weight on extreme exercise days.

Carbohydrate timing and amounts can be manipulated around exercise sessions. Most often, an athlete strives to target high carbohydrate availability around their workouts with the rest of their diet being more flexible.



Protein in the range of 1.2 to 2.0 g/kg body weight supports the needs of most athletes. Protein needs can be met through diet, and supplements are not required.

Athletes wishing to choose protein supplements should check that their preferred supplement is listed on the NSF International Certified for Sport site to reduce their risk of inadvertent doping. Children and adolescents should be discouraged from using supplements altogether.



Fat is a necessary component of an athletes diet. Healthy fats, like omega-3 fats, help with recovery, injury prevention, provide energy, and are implicated in concussion management by both reducing the severity of a concussion and hastening brain healing.



Athletes do best when they begin to exercise in a hydrated state. Decrements in performance may appear when athletes lose more than 2% of their body weight during exercise.

For optimal hydration:

  • Athletes should start activity well hydrated by drinking approximately 5-7 ml/kg of fluid 2-4 hours before starting exercise;
  • During exercise lasting less than an houronly water is needed;
  • For activity lasting longer than 1-1.5 hours, both carbohydrates and water are beneficial. As such, choosing a sports drink for hydration during intense workouts and more prolonged exercise makes sense;
  • After exercise, athletes should aim to drink to replenish 125-150% of body weight losses from the activity.


Vitamins and Minerals

When athletes eat a varied diet, without restriction, and meet their energy needs for weight maintenance, they achieve their requirements for most vitamins and minerals through diet alone.

Athletes at risk for vitamin and mineral deficiencies include those who are restrained eaters; eliminate food groups because of allergies, sensitivities or beliefs; and those who are trying to lose weight. In addition, athletes training at altitude have higher needs for iron, and those routinely practising indoors or who have high levels of body fat have a higher risk of vitamin D deficiency. Clinicians can support their athletes by encouraging regular routine blood work to monitor such indices as vitamin D and iron.

micronutrients distribution in nutrium software

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Planning for Training and Rest Days

Nutrition around exercise is more critical for those engaging in a heavy and lengthy activity. Individuals who participate in light, short-duration exercise can meet their needs with a generally healthy diet.

macronutrients distribution in nutrium software

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Athletes should begin each training session in a fed state, particularly quality sessions. Also, they should practice competition eating in advance of their game or event. Athletes may benefit from the following approach:

Before exercise:

  • Choose high carbohydrate (1-4 g/kg), lower fat and fibre, and* moderate protein* meals and snacks 1-4 hours before exercise;
  • Fluid in the amount of 5-7 ml/kg is helpful for many athletes.

During exercise:

  • Less than 1 hour: only water is required;
  • For moderate to intense exercise lasting longer than 1-1.5 hours: choose 30-60 g of carbohydrates every hour, and drink water or sports drink to thirst;
  • For events lasting longer than 2.5 hours, choose carbohydrates (from mixed sources like glucose and fructose) up to 90 g an hour, and drink water or sports drink to thirst.

After exercise (within 30-60 minutes):

  • Consume 1-1.5 g/kg of carbohydrates to replenish glycogen stores, particularly if engaging in another bout of exercise on the same day;
  • Eat protein in the amount of 0.25-0.4 g/kg;
  • Rehydrate well. During the post-exercise period, those who sweat heavily and are salty sweaters will likely benefit from choosing foods or beverages containing salt.


Athletes benefit from eating to meet their daily demands and targeting fueling techniques around exercise. By prioritizing nutrition, an athlete can enhance performance and reduce their risk of injury and illness.





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