Sports Nutrition- A Guide to Eating Right

Nutrition is an important part of sports performance for the young and the old. There is a direct link between good health and good nutrition. Macro and Micro nutrients as well as different vitamins and minerals are extremely important to maintain a balanced diet. 

Whether you are an athlete, a weekend sports player or a daily exerciser, a nutritionally adequate diet is the cornerstone of improved performance. 

Daily training diet requirements- 

The basic training diet should be sufficient to- 

 

1. Provide enough energy and nutrients to meet the demands of training and exercise. 
2. Enhance adaptation and recovery between sessions. 
3. Include a wide variety of wholegrain foods, vegetables (Especially green leafy),fruit ,low fat dairy products and if suitable lean meats to enhance long term nutrition habits and behaviours. 
4. Enable athletes to reach their optimal body composition, weight and performance.
5. Provide enough fluids to provide adequate hydration before, during and after workouts.
6. Promote the short and long terms of health.

 

An athlete’s diet is similar to that required for the general public.In general,  the following macronutrient goals work best: 60% carbohydrates, 20% protein, and 20% fat for cardiovascular athletes; 45% carbohydrates, 30% protein, and 25% fat for weight training athletes; and 55% carbohydrates, 25% protein, and 20% fat for both cardiovascular and weight training athletes.

Fat as fuel 

Fat is the primary fuel for light to moderate intensity exercise. Fat is a valuable metabolic fuel for muscles during endurance exercise and performs many important functions in the body, although it does not provide quick bursts of energy needed for speed.

The more efficient an athlete becomes in their respective sport, the easier it is for them to operate at a lower intensity while maintaining the same level of work or maintaining the same speed (metabolic efficiency).

At this lower intensity, stored fat in the muscle can be used as a fuel source. The average 150-pound athlete with 6% body fat carries 1,500-2,000 calories in the form of carbohydrates and more than 45,000 calories in the form of fat. Even for efficient endurance and ultra-endurance athletes, carbohydrates are still important, but stored fats help them reach the finish line.

 

Glycemic Index (GI) and sports nutrition 

The glycaemic index (GI) ranks food and fluids by how ‘carbohydrate-rich’ they are and how quickly they affect the body’s blood sugar levels. The GI has become of increasing interest to athletes in the area of sports nutrition.

 There is a suggestion that low GI foods may be useful before exercise to provide a more sustained energy release, although evidence is not convincing in terms of any resulting performance benefit.

Moderate to high GI foods and fluids may be the most beneficial during exercise and in the early recovery period. However, it is important to remember the type and timing of food eaten should be tailored to personal preferences and to maximise the performance of the particular sport in which the person is involved.

 

Carbohydrates and sports performance 

Adequate carbohydrate intake can prevent muscle breakdown from glycogen depletion and prevent hypoglycemia, both of which have been independently proven to reduce athletic performance.2 During exercise, glycogen stores are depleted as muscle glycogen is converted to glucose and used for energy. Once this happens, the body needs alternative fuel sources and will turn to protein and fat in a process called gluconeogenesis. Having enough glycogen on board before exercise and refueling during workouts can help preserve skeletal muscle integrity during exercise. And as exercise intensity is increased, glycogen becomes progressively more important as a fuel source. Enhancing the muscle’s capacity to store glycogen can improve performance in sports where glycogen depletion would hinder athletic performance. 

 

 Pre-event meal

The pre-event meal is an important part of the athlete’s pre-exercise preparation.

A high-carbohydrate meal 3 to 4 hours before exercise is thought to have a positive effect on performance. A small snack one to 2 hours before exercise may also benefit performance.

It is important to ensure good hydration prior to an event. Consuming approximately 500 ml of fluid in the 2 to 4 hours prior to an event may be a good general strategy to take.

Some people may experience a negative response to eating close to exercise. A meal high in fat, protein or fibre is likely to increase the risk of digestive discomfort. It is recommended that meals just before exercise should be high in carbohydrates as they do not cause gastrointestinal upset.

Examples of appropriate pre-exercise meals and snacks include cereal and low-fat milk, toast, fruit salad and yoghurt, pasta with tomato-based sauce, a low-fat breakfast or muesli bar, or low-fat creamed rice.

 

Eating after exercise

Rapid replacement of glycogen is important following exercise.

Carbohydrate foods and fluids should be consumed after exercise, particularly in the first one to 2 hours after exercise.

While consuming sufficient total carbohydrate post-exercise is important, the type of carbohydrate source might also be important, particularly if a second training session or event will occur less than 8 hours later. In these situations, athletes should choose carbohydrate sources with a high GI (for example white bread, white rice, white potatoes) in the first half hour or so after exercise. This should be continued until the normal meal pattern resumes.

Suitable choices to start refuelling include sports drinks, juices, cereal and low-fat milk, low-fat flavoured milk, sandwiches, pasta,fruit and yoghurt.

Since most athletes develop a fluid deficit during exercise, replenishment of fluids post-exercise is also a very important consideration for optimal recovery. It is recommended that athletes consume 1.25 to 1.5 L of (non-alcoholic) fluid for every kilogram of body weight lost during exercise.

 

Protein and sporting performance

Protein is an important part of a training diet and plays a key role in post-exercise recovery and repair. Protein needs are generally met (and often exceeded) by most athletes who consume sufficient energy in their diet.

The amount of protein recommended for sporting people is only slightly higher than that recommended for the general public. For example:

• General public and active people – the daily recommended amount of protein is 0.8 to 1.0 g/kg of body weight (a 60 kg person should eat around 45 to 60 g of protein daily).
• Sports people involved in non-endurance events – people who exercise daily for 45 to 60 minutes should consume between 1.0 to 1.2 g/kg of body weight per day.
• Sports people involved in endurance events and strength events – people who exercise for longer periods (more than one hour) or who are involved in strength exercise, such as weight lifting, should consume between 1.2 to 2.0 g protein/kg of body weight per day.
• Athletes trying to lose weight on a reduced energy diet – increased protein intakes up to 2.0 g/kg of body weight per day can be beneficial in reducing loss of muscle mass.

For athletes interested in increasing lean mass or muscle protein synthesis, consumption of a high-quality protein source such as whey protein or milk containing around 20 to 25 g protein in close proximity to exercise (for example, within the period immediately to 2 hours after exercise) may be beneficial.

As a general approach to achieving optimal protein intakes, it is suggested to space out protein intake fairly evenly over the course of a day, for instance around 25 to 30 g protein every 3 to 5 hours, including as part of regular meals.

There is currently a lack of evidence to show that protein supplements directly improve athletic performance. Therefore, for most athletes, additional protein supplements are unlikely to improve sport performance.

While more research is required, other concerns associated with very high-protein diets include:

 

• potential negative impacts on bones and kidney function
• increased body weight if protein choices are also high in fat
• increased cancer risk (particularly with high red or processed meat intakes)
• displacement of other nutritious foods in the diet, such as bread, cereal, fruit and vegetables.

 

Using nutritional supplements to improve sporting performance

A well-planned diet will meet your vitamin and mineral needs. Supplements will only be of any benefit if your diet is inadequate or you have a diagnosed deficiency, such as an iron or calciumdeficiency. There is no evidence that extra doses of vitamins improve sporting performance.

Nutritional supplements can be found in pill, tablet, capsule, powder or liquid form, and cover a broad range of products including:

• vitamins
• minerals
• herbs
• meal supplements
• sports nutrition products
• natural food supplements.

Before using supplements, you should consider what else you can do to improve your sporting performance – diet, training and lifestyle changes are all more proven and cost effective ways to improve your performance.

 

It’s best if dietary imbalances are adjusted after analysing and altering your diet, instead of by using a supplement or pill.

 

Water and sporting performance

Dehydration can impair athletic performance and, in extreme cases, may lead to collapse and even death.

Drinking plenty of fluids before, during and after exercise is very important. Don’t wait until you are thirsty. Fluid intake is particularly important for events lasting more than 60 minutes, of high intensity or in warm conditions.

Water is a suitable drink, but sports drinks may be required, especially in endurance events or warm climates. Sports drinks contain some sodium, which helps absorption. A sodium content of 30 mmol/L (millimoles per litre) appears suitable in sports nutrition.

While insufficient hydration is a problem for many athletes, excess hydration may also be potentially dangerous. In rare cases, athletes might consume excessive amounts of fluids that dilute the blood too much, causing a low blood concentration of sodium. This condition is called hyponatraemia, which can potentially lead to seizures, collapse, coma or even death if not treated appropriately.

Consuming fluids at a level of 400 to 800 ml per hour of exercise might be a suitable starting point to avoid dehydration and hyponatraemia, although intake should ideally be customised to individual athletes, considering variable factors such as climate, sweat rates and tolerance.