Facts about Fitness: General Nutrition Guidelines for Athletes and Physical Activity Benefits

This blog focuses on nutrition and its effects on all aspects of life, which includes fitness. There are certain nutritional needs and concerns when it comes to an athlete or anyone who wants to live a healthy, active lifestyle. Optimal nutrition is an essential part of every athlete's training program (Heber 139). The primary areas of concern are: 1) consuming enough calories to support performance, 2) consuming the correct balance of macronutrients before, during, and after exercise, and 3) proper hydration (Heber 139). "Facts about Fitness" entries will focus on these components.

General Nutrition Guidelines (Heber 139-141)

To maximize performance, athletes (i.e. any person who exercises or participates in a sport) generally want to achieve an optimum sport-specific body size, body composition, and mix of energy stores. While there may be some variation by sport, generally speaking, athletes require at:

• ~15% calories from proteins
• ~25% or less calories from fats
• Remaining calories supplied by carbohydrates

Again, it varies per activity and sport, so nutritional intake is optimal based on the how extraneous the exercise is. Total number of calories consumed also needs to be considered, and is highly variable depending on the body size, gender, and sport of the athlete. Athletes should aim to achieve carbohydrate intake to meet the fuel requirements of their training program and to optimize restoration of muscle glycogen stores between workouts. 

The most important objective of periodization of daily carbohydrate intake would be to ensure high muscle glycogen levels at the start of the hard training sessions. To raise muscle glycogen to high levels, athletes should eat a total of 7-12 grams of carbohydrate/kg body weight during recovery from the last training session. The recovery period should not be less than 24 hours. However, during the 24 hours prior to a moderate or easy day of training, it may be satisfactory for athletes to eat 5-7 grams of carbohydrate/kg. If muscle glycogen is not fully recovered and the athletes sense this as a feeling of slight residual fatigue, they may refrain from exercising too intensely. 

An athlete's daily energy intake should generally match energy expenditure to minimize hunger and stress. Fluctuations in carbohydrate intake can be matched by inverse fluctuations in calories from fat and/or protein. Thus, on the day before an easy day of training, if athletes choose to eat a moderate amount of carbohydrate (5 g/kg), they can appropriately increase their intake of healthy fat and lean protein. In addition to providing them with a varied diet to satisfy taste, the extra dietary fat may help to raise the concentration of intramuscular triglyceride (i.e. a source of muscle fuel). Extra protein may also be beneficial on a periodic basis.

For endurance athletes (i.e. long-distance running, marathoners, etc.), the most important aspect is that they should not exercise for 20-24 hours prior to a hard training session, and during that time they should consume 7-12 grams of carbohydrates/kg of body weight. Furthermore, many athletes attempt to reduce body fat as much as is appropriate for their particular sport. Therefore, the simple advice is that eating a high-carbohydrate diet may cause concern that it may lead to a positive energy balance and a gain in body fat. The amount of carbohydrate can represent either a relatively large or small portion of an athlete's daily energy needs depending on the sport.

In all but a few exceptional cases, the contribution of protein as an energy source during exercise ranges from 2-10% of total energy expenditure. This will vary, depending on the type of exercise, its duration and intensity, and individual's previous diet. Active endurance exercise results in the oxidation of several amino acids, and a low energy or low carbohydrate intake could increase total protein requirements. However, with adequate calories and carbohydrates, low to moderate intensity endurance activity has little impact on dietary protein requirements. In strength-trained athletes (i.e. weight-lifters, football players, etc.), an increased protein requirement may arise due to catabolic loss (i.e. breakdown) of amino acids associated with resistance training. At the same time, studies have shown that strength training can increase the efficiency of use of dietary protein. Given the relatively high energy needs of the athlete, however, those who consume even 15% of total calories from protein will consume absolute amounts in excess of 100 grams per day to support muscle growth and recovery. Athletes involved in strength training activities are advised to consume ~1.6 g protein/kg of weight per body.

Benefits of Physical Activity and Exercise (Heber 150-152)

I know what you're thinking, and yes, there are actual benefits of physical activity and exercise. Believe it or not, such benefits include:

• Decrease in loss of fat-free mass associated with weight loss
• Improvement in maintenance of weight loss
• Improvement in cardiovascular and metabolic health, independent of weight loss (Heber 150)

The energy used in various forms of exercise and physical activity ranges per activity. It takes a lot of physical activity to burn enough calories to make a difference in weight loss. Physical activity does NOT increase the rate of weight los but it is important strategy for maintaining weight loss in the long-term. Overall, you need to do over 200 minutes per week (i.e. 3 1/3 hours per week) or ~30 minutes per day to maintain weight loss. The reasons why will be discussed in the next entry, which will cover fuel utilization during exercise. 

Me as an Example

Me at my first BJJ tournament (Brea-Jiu-Jitsu tournament); won this match 10-2. Photo credit to Judy + Gavin Photography.

So, I currently live a moderately active life-style, as I am currently training in Brazilian Jiu-Jitsu 3-5 times a week, 1-2 hours per practice. I occasionally lift weights and do cardio in order to build up my stamina and endurance. As this martial arts requires more direct combat via grappling, it also requires strength and coordination in terms of physical activity. The goal is to use your opponent's body weight and leverage against him/her, which requires to put a person in a submission or head/leg/arm lock. I am currently working toward my blue belt, which means that I have to put in more practices and sessions. As a result of this active lifestyle, I have to make sure that I have enough energy and mental fortitude to roll with my opponents, as the martial arts involves both strength and technique, both physical and mental. 

Me getting choked out - it was tough. I lost this match, but I am even more motivated. Photo credit to Judy + Gavin Photography.

Got tied for third! This is only the beginning; aiming for 1st next time. Photo credit to Judy + Gavin Photography.

After each practice, I have to make sure that I get in sufficient nutrients; I generally aim for the guidelines above, but also school and convenience play a role. I am a student first, athlete second, so my nutrition is based on my class/research/work schedule. Usually, I would have meals prepared before-hand by preparing them in bulk (i.e. cooking every meal all at once). It is cost-efficient and saves time. However, I can sometimes stray from this and order from Panda Express in Ackerman or In-n-out in Westwood. Hey, I ain't perfect but I strive for excellence. I try not make it a habit, as decisions define who I am - and can be.

Preparation of my meal for the day by cooking in bulk.

Breakfast, lunch, and dinner. Ready to go!

Sometimes, classes can get the best of me, and I have to settle for convenience - my usual order: 2 double-doubles and fries.

In addition to BJJ, I also love biking, hiking, running, and anything outdoors. May 4th of this year, convinced by my good friend Kim, I ran our first marathon! The OC marathon! It was fun yet challenging; 26.2 miles can definitely test your will-power and push who you really are. Took months of training but worth it!!! My cross-country and track-and-field in high school background definitely helped me here. After the full marathon, I was aching in pain. I couldn't climb the stairs for a week. Boy, that was fun...

Kim and I before the marathon. As Kim put it, "Before we die..."

I had to make sure that the medal was real. Finished in 4 hours and 32 minutes. WOOT!

Kim, Shirley, and I enjoying our well-deserved beers at the end. No worries, we are all 21.

Overall, I had a productive year so far in terms of my fitness goals. However, this is only the beginning. Some but not all of my fitness goals for this year and next: 

• Doing the LA marathon 2015
• Doing an Ironman challenge (i.e. a triathlon of 2.4-mile swim, 112-mile bike ride, and 26.2-mile running)
• Earning my blue belt in BJJ after many, many hours of smart training
• Continue my exercising along with excelling in school. 

The journey ahead is uncertain, but nutrition serves as my compass.

Information about general nutrition guidelines for athletes and physical activity benefits was taken from Dr. Heber's course reader, Winter 2014 (pages have been cited). All photos were taken by me unless otherwise noted in the caption.