Recent Evidence-Based Nutritional Guidelines

There are general guidelines that Certified Personal Trainers should be aware of when it comes to nutritional recommendations to support increased physical activity.  Recently, the Academy of Nutrition and Dietetics published a position paper outlining recent research on sports nutrition guidelines; therefore, I wanted to share findings which are evidence-based. Keep in mind that these are general guidelines for athletes. Clients should be referred to sports dietitians for individualized nutritional assessments, especially clients with health conditions such as diabetes, kidney disease, heart disease, hypertension, gastrointestinal issues, vitamin/mineral deficiencies and other conditions.

Energy (Caloric) Recommendations:

Energy requirements will vary based on type of workout routine (volume and intensity) and whether clients need to lose, gain, or maintain weight. Other factors to consider that will increase energy needs include high altitude exposure, cold or heat exposure, physical injuries, medications, and phase of menstrual cycle. 

In order for clients to maintain weight, energy in (calories) should equal energy out (expenditure).  For weight loss, intake should be less than expenditure, and for weight gain, energy in should be higher than expenditure.  It is important to remember that bodyweight should not be the sole consideration.  It is best to measure bodyfat percentage and lean muscle in clients to ensure that muscle is not being lost due to insufficient energy intake.  In order to avoid loss of performance, achieving a light energy deficit is preferable versus a deficiency that promotes rapid weight loss as lean muscle may be compromised.

A general guideline is to decrease energy intake by 250 to 500 calories a day while maintaining or slightly increasing energy expenditure.

Carbohydrate Recommendations:

Carbohydrates are key fuel for the body and should be recommended in adequate amounts. It is important to maintain high carbohydrate availability (glycogen stores and blood glucose) to minimize fatigue and decreased concentration, and to sustain lean muscle.  Carbohydrate recommendations vary according to amount/intensity of exercise, and are provided as grams per kilogram.  In order to convert pounds to kilograms, divide pounds by 2.2.  Hence, 110 lbs = 50 kg. Recommendations based on expenditure are as follows:

*Low intensity or skill based activity:  3.5 grams per kilogram of athlete’s bodyweight per day.

*Moderate intensity or moderate exercise program (about an hour a day):  5-7 grams per kilogram of athlete’s bodyweight per day.

*High intensity or endurance program (about 1-3 hours a day moderate to high intensity):  6-10 grams per kilogram of athlete’s bodyweight per day.

*Very high or extreme program (about 4-5 hours per day moderate to high intensity):  8-12 grams per kilogram of athlete’s bodyweight per day.

Protein Recommendations:

Proteins are key for maintaining muscle mass and connective tissues (tendons, bones). Inadequate protein intake will have a negative impact on lean muscle synthesis and repair; however, excessive protein intake may have a negative impact on body function as well as body is working hard to eliminate excess protein. Keep in mind that adequate carbohydrates are needed so that protein synthesis is not impacted.

Protein guidelines range from 1.2 to 2.0 grams per kilograms per day. Additionally, protein intake is encouraged in terms of regular spacing (0.3 grams per kilogram of bodyweight after exercise and throughout the day). These intakes can be met from food sources versus supplements.

Fat Recommendations:

Fats are key in providing energy and are essential elements for cell membranes and absorption of fat-soluble vitamins. Saturated fats should be limited to less than 10% of total calories per day; therefore, fat intake should mostly come from unsaturated fats. We should discourage clients to reduce fat intake below 20% as a way of losing fat since our bodies need fat-soluble vitamins and essential fatty acids. Hence, a general guideline is that total fat intake should range from 20-35% of calories per day.

Fluid Recommendations:

Adequate hydration leads to optimal health and exercise. Fluid intake will vary depending on environmental conditions (heat, cold) and amount of sweat.  Dehydration is a concern; however, over-hydration can be dangerous as well. Because fluid intake depends on many factors, there is no general guideline specified in this particular article.  A specific post-exercise recommendation made by current research suggests 1.25 to 1.5 liters of fluid replenishment for every kilogram of bodyweight lost per exercise. One liter is equivalent to four cups.

Alcohol:

Overconsumption of alcohol can interfere with fitness goals as it suppresses breakdown of fat, and increases energy intake.  Alcohol intake can have a negative impact on strength and performance several hours after ingestion by interfering with glycogen storage and affecting hydration.   Alcohol should be minimized or avoided during post-exercise period while muscles and tissues are recovering.

Vitamin/Mineral Supplements:

If clients are meeting the above requirements, supplementation may not be necessary unless an energy restricted diet is in place.  Supplementation should be individualized and, hence, assessed by a sports dietitian.

For more detail on these findings, please refer to the actual article (reference below) as I am only presenting a brief synopsis.

Reference:

Travis, D.T., Erdman, K.A., & Burke, L.M. Position of the Academy of Nutrition and Dietetics, Dietitians of Canada, and the American College of Sports Medicine:  Nutrition and athletic performance. Journal of the Academy of Nutrition and Dietetics. 2016, 116(3): 501-528.

Susan Ricardo Buckley, MS, RD, LD/N, CPT is a Registered / Licensed Dietitian and Certified Fitness Trainer with over twenty years of experience in the field of teaching, nutrition, fitness and administration. She earned her Master’s of Science degree in Dietetics and Nutrition (2000) as well as a Bachelor’s in Business Administration (Human Resources Management with a minor in Psychology, 1987) from Florida International University in Miami, Florida. Susan has been certified with the National Federation of Professional Trainers since 1994. Her field experience includes wellness consulting; i.e., medical nutrition therapy, nutrition/fitness counseling, and public speaking.