In the last decade, the health and fitness industry has grown exponentially with an increased focus placed on the importance of sports nutrition. It is widely recognised that nutrition is a key factor for improved performance in athletes, however the general public are catching onto the importance of fueling your body for exercise and adequate recovery. Sports nutrition is widely defined as a highly specialised area in the field of nutrition that works closely alongside the human body and exercise science1. More specifically, this discipline centres on manipulating one’s diet for a specific exercise goal, whether that be for competition, muscle gain or weight loss.
Macro and Micronutrients
Before understanding how to manipulate an individuals diet, it is necessary to understand the basics of how food is broken down in the body. Every food or drink we consume is composed of 6 essential nutrients, split into 2 categories named macronutrients and micronutrients. These essentially are what calories in our food consists of.
Macronutrients consist of proteins, carbohydrates and fats; the type of nutrients we need to consume a large amount of daily. Carbohydrates are broken down by the enzyme amylase in the mouth and stomach and converted into glucose which enters the bloodstream. Any unused glucose gets stored as glycogen in the liver and muscle cells. Secondly, Fats are broken down by an enzyme called lipase and bile from the gallbladder. Fats are broken down into the precursor components called fatty acids. These are used for energy when glycogen stores are depleted, or are stored in adipose tissue. Proteins cannot be stored in the body, they are broken down by protease and either enter the blood or are converted into other useful molecules in the body by a process called deamination (removing the ammonia component of a molecule) that occurs in the liver.
Micronutrients consist of vitamins, minerals and water. Named ‘micro’ because the body requires these nutrients in much smaller amounts. Each vitamin mineral has an individual pathway as to how it is broken down and absorbed in the body. ‘Macros’ and ‘micros’ work synergistically and by altering the amounts of these nutrients is how desired fitness of body image goals can be reached.
The government and NHS guidelines for recommended calorie intake are extremely broad. For example, they suggest 2,000kcal and 2500kcal to be eaten each day for adult women and men respectively2,3. This is questionable as this does not take into consideration a persons height, weight, age or even their activity level. All of these factors have a direct impact on the amount of calories you need each day. A more accurate method to determine how much you should be consuming on a daily basis is by using the Mifflin St. Jeor equation4. The result of this equation determines a person’s Basal Metabolic Rate/BMR (the calories they would burn in a day simply by being alive). It is from this number that calories can be adjusted more accurately for weight loss/ gain on a more personalised level. There are various online calculators you can enter your details and your BMR will be calculated for you automatically. For weight loss, it is recommended to reduce the resulting number by 500.
One of the main reasons for the increased interest in sports nutrition is from the a pressing demand from people seeking weight loss. The most basic perspective of this goal is that if an individual would like to lose weight, calories in must be cut. Basically, the calorie intake generated from food and beverage consumption should be LESS than the energy they use to survive, exercise etc. It is a well-known face that 1 pound of body weight is equated to 3,500 calories. Therefore to lose 1 pound per week an individual must consume 500 fewer calories each day or burn 500 calories more through exercise.
Again, macronutrients can be manipulated to enhance this process. Weight loss fad diets are a prime example of this; the Atkins diet focuses on a very low consumption of carbohydrates in an attempt to switch the body’s energy source to fats. However, there is no need to go to such extremes, especially as these diets can be damaging to your health in the long run. A basic rule of thumb in the industry is to follow the 40/30/30 principle. This essentially means 40% of calories are obtained from carbohydrates, 30% from protein and 30% of healthy fats.
Nutrition for Athletes
With regard to athletic performance, it is essential to study the physiology of the sport in order to understand what the body requires in higher amounts to fuel the athlete. For, example an elite marathon runner and an Olympic Power lifter will need completely different amounts of macro and micronutrients despite both being at the top level of sport. Not only is it important to understand what the athlete needs to eat habitually, it is crucial to also recognise what needs to be manipulated before and after competition to maximise performance and enhance recovery.
Let’s use the example of the marathon runner; it is an endurance based sport in which the athlete performs for extended periods of time. From this alone, it is clear that this athlete will need a high energy intake to fuel their body for the long duration of their race and training sessions. The body’s primary energy source is glycogen, the storage form of carbohydrates. Typically, sport’s nutritionists would recommend this type of athlete to consume around 60% of their calories from carbohydrates or 5-7 grams per kilogram of body weight. This value may be even higher depending on athletic ability. You may think this consumption of carbohydrates seems excessive but it ensures there is adequate glycogen stores for performance.
When an athlete has a low intake of carbohydrates, the body metabolises energy through a slightly different mechanism. It switches to protein as its primary source of energy. This can be extremely detrimental for an athlete as protein is an important element of muscle growth and repair. This is why a major part of sport’s nutrition, and particularly sports supplements are protein powders. To make up for what is lost during exercise and repair the body post-exercise.
Moreover, for exercises lasting for long periods of time, fats are almost equally as important as carbohydrates as they carry more energy per gram than carbohydrates and protein combined (9kcal/g). At the top level of performance athletes are extremely responsive to very small changes to their diet. There are certain techniques for example ‘carb-loading’ where glycogen stores can be manipulated to become more efficient during competition and provide energy when most needed.
Nutrient timing is an extremely important concept in sports nutrition. Nutrient timing is basically at what times meals are consumed in regard to training and performance to allow maximum performance and recovery. This must also be considered if you have a specific goal in mind by affecting the activity of specific hormones.
At any time in the day, the body is set for weight gain or fat loss and when food is consumed can intensify those efforts. It is generally recommended that 3-5 meals are consumed throughout each day and the timing of these will depend on when you choose to exercise. In order to properly fuel a workout and allow time for digestion, 1-2 hours before the start of activity is normally enough time especially because the meal should be mainly be composed of complex carbohydrates providing slow release energy. After a training session, there is a period of time called the ‘anabolic’ window which lasts around 1-2 hours5 .At this specific point in time, the body is primed for muscle growth and repair due to increased sensitivity of insulin. Insulin is an anabolic ‘building’ hormone, with the increased sensitivity leading to more glucose and amino acids to be transported into the muscle cells permitting growth and repair. The increased sensitivity of insulin is coupled with the down-regulation of the catabolic ‘breakdown’ hormone glucagon. Glucagon breaks down the stored form of carbohydrates in our body, glycogen, into glucose used for energy which will inhibit the amount entering muscle cells. Therefore, it is essential to consume an adequate amount of calories in this short window. A general rule supported by scientific evidence is to consume carbohydrates and proteins in a 2:1 ratio. Some good examples of this are chocolate milk or Greek yoghurt with a banana.
Supplements are an extremely useful addition to the diet, but is important to remember that they are just that, they are used to supplement a good diet not make one. They are not a magic means to reaching a goal, but can certainly assist and boost your natural gains. The popularity of supplements is still on the rise, UK Sports Nutrition related sales have increased by 27% in the last 2 years meaning that 1 in 4 of us will use some kind of supplement6. It is important to note that when taking vitamins and minerals, the most benefits can be seen if you are deficient in them. For example, someone who has a very low level of Vitamin D will feel more of an effect after supplementation than someone who has an adequate level. There are many ways to test for vitamin deficiency including a blood test or a complete meal analysis from a qualified Nutritionist.
Supplements are an almost an essential aspect of sports nutrition, regardless of the sport or level. Some are considered ‘ergogenic aids’, or a supplement/ nutrient with the ability to improve performance. One of the most tested and proven supplements is Creatine Monohydrate. Creatine can be found naturally in foods however supplementation is extremely effective especially in movements lasting 10 seconds or less. Creatine acts in the body by donating a phosphate group to the compound ADP to make ATP (the main energy compound in the body), helping to improve performance in short duration, high intensity exercise and 3-5grams is recommended to be taken each day prior exercise.
Nadia Farrugia | Oxford Vitality Nutritionist
Don't Miss Out!
Sign up now to receive our offers, news and weekly articles right to your inbox!
- When looking at the whole picture with sports nutrition there are a few key points to remember:
- Make sure you fuel your body to be efficient as possible, this means eating before and after exercise. Do not be afraid to eat!
- If you are trying to lose some pounds do not get caught up the hype of fad diets and supplements; keep it simple and make sure what you eat is less calories than what you burn on a daily basis.
- Try and monitor the proportion of carbohydrates, fats, and protein you eat by following the 40/30/30 proportion rule of macronutrients.
- If you are looking to gain lean muscle make sure you are consuming more calories than you are burning.
- One final and extremely important piece of advice is to stay hydrated!
1. Practical Applications in Sports Nutrition. chapter 1 page 1
2. Dietary Reference Values for Food Energy and Nutrients for the United Kingdom. Report of the Panel on Dietary Reference Values of the Committee on Medical Aspects of Food Policy. Department of Health (1991)
4. MD Mifflin, ST St Jeor, et al. A new predictive equation for resting energy expenditure in healthy individuals. J Am Diet Assoc 2005:51:241-247.
5. Ivy JL. Glycogen resynthesis after exercise: effect of carbohydrate intake. Int J Sports Med 19 Suppl 2: S142-S145, 1998.
6. Mintel’s Attitudes towards Sports Nutrition UK 2016 Report