I. BASICS OF NUTRITION

Introduction
Proper nutrition in combination with adequate exercise and emotional well-being is the key to optimal performance of human mind and body. Lately, lot of research has been done in the field of dietetics. But all these studies have certain inherent limitations. One of the major limitations of these studies is that they have often been conducted on small groups of population or on rats in the laboratories. Even within the same group, different members have responded in different ways to dietary stimulus. For example, in many case studies, where the group was put on the same diet and exercise regimen, some of the group members gained weight, while the others did not gain any weight at all. However, despite all these limitations there are certain basic principles of nutrition which are supported by scientific research as well as by empirical findings.

Preparation of diet plan is not a matter of plain arithmetics in which calculations are made on the basis of calories, proteins, carbohydrates, vitamins, etc. A balanced diet plan for an individual has to take into account several other important factors, e.g., age, gender, nature of physical and mental work, health status, sensitivity to a particular food, income, family food tradition etc. This section explains the basics of nutrition and provides broad guidelines for diet planning.

Principles of nutrition

There are three basic principles of nutrition:- –
(i) Our body requires six essential nutrients, viz., proteins, carbohydrates, fats, vitamins, minerals and water.
ii) These nutrients are found in four basic food groups, viz., (a) cereals (b) vegetable/fruits, (c) meat/meat substitutes, (d) dairy products
iii) The food items from these groups have to be consumed each day in the way that our maximum food intake comes from cereals followed by vegetables/fruits, meat/meat-substitutes and dairy products.

Food guide pyramid
US Department of Agriculture (USDA) has developed the following food guide pyramid as guidelines for daily dietary intake from different food groups, which can be useful for us also.



Important – The number of servings given in the food pyramid is recommended for the entire day. For example, 4 slices of breads in the breakfast, ½ cup rice in the lunch, 4 chapatis in the dinner, ½ cup dal in the lunch and ½ cup dal in the dinner taken together will provide 9½ servings from the bread/cereal group.

Vegetarian or non-vegetarian? This is one of the most frequently asked questions, especially by vegetarian sportspersons – Can I compete against non-vegetarians on a vegetarian diet only ?

To this question, my answer will be – Yes! Look at these vegetarian sportspersons –

1. Carl Lewis – One of the fastest athletes in the world, in 1991 broke the world record for 100 meters in 9.86 seconds.
2. Martina Navratilova – The first tennis player to win Wimbledon nine times (six being consecutive).
3. Edwin Moses – From 1977 to 1987 achieved 122 victories in the 400 meter hurdles. Won two Olympic gold medals, two world titles, four world records and a streak of 122 consecutive victories.
4. Paavo Nurmi – Great marathon runner, achieved 20 world records with nine Olympic gold medals. In 1924 Olympic Games, he won the 1500 meters and the 5000 meters with just one hour of rest between the two events.
The diet of Tarahumara Indians, a tribe of North Central Mexico is mainly vegetarian. They are known for their extraordinary endurance ability. During their popular sport ‘Raripuri’ the participants run for 150-300 kms, repeat, 150-300 kms!

Who is a vegetarian?

In fact, vegetarianism has its own different shades. For example, ‘Lacto-vegetarians’ do not eat meat, fish, fowl and eggs, but they eat dairy products. ‘Lacto-ovo-vegetarians’ avoid meat, fish and fowls but include dairy products as well as eggs in their diet. ‘Vegans’ simply avoid all animal products including meat, fish, fowl, eggs, dairy products and even honey. In India, a traditional vegetarian diet falls somewhere in ‘Lacto-vegetarian’ category. In our analysis, those who rarely consume meat can also be called vegetarians by and large.

Advantages of non-vegetarian diet
(i) It is rich in protein.
(ii) It provides complete protein and has all essential amino acids.

Disadvantages of non-vegetarian diet
(i) Too much of meat consumption means too much intake of protein. Excess protein intake is fraught with many health risks. Studies have found that diets rich in protein cause excretion of more calcium through urine, thereby increasing the risk of osteoporosis (thinning of bones).
(ii) Non-vegetarian diet is high in saturated fats. High intake of saturated fats is associated with major risk factors of cardiovascular disease.
(iii) It is high in cholesterol. Again, high cholesterol is associated with major risk factors of cardiovascular disease.
(iv) It is low in roughage and therefore promotes constipation.
(v) It is low in vitamins.

Advice to non-vegetarian

(i) Select those animal products which are comparatively low in saturated fats and cholesterol, e.g., chicken is preferable to beef, egg whites to egg yolk.
(ii) Consume meat within a reasonable limit to avoid excess intake of protein, saturated fat and cholesterol.
(iii) Take adequate carbohydrates.
(iv) Include green vegetables and salads in your diet for roughage and essential vitamins.

Advantages of vegetarian diet

(i) It is high in carbohydrate, the principal source of energy.
(ii) A diet based on cereals, vegetables, fruits does not have saturated fats and cholesterol and thereby reduces the major risk factors associated with cardiovascular disease.
(iii) It is rich in vitamins and minerals.
(iv) It has plenty of roughage facilitating good bowel movement.

Disadvantages of vegetarian diet

(i) It is generally low in protein.
(ii) It does not contain all essential amino-acids. Low protein intake may result into low muscular gain.

Advice to vegetarians

(i) Combine two or more cereals or vegetable proteins for getting all essential amino acids. For example, combine rice or wheat with soybeans/pulses/legumes/lentils. Actually, this is what traditional Indian diet usually includes. By this method of combination (mutual supplementation), you can compensate individual amino acid deficiency of a vegetable protein.
(ii) You can increase protein intake by simply increasing your caloric intake, e.g., take additional cup of moong sprouts or additional cup of milk.
(iii) Include low fat dairy products in your diet.

Back to top >

II. PROTEINS

Importance of proteins
(i) Proteins are important for building and repairing of all cells and tissues, including internal organs, muscles, blood cells, brain, bones and skin.
(ii) Proteins are components of enzymes and some hormones which regulate our body’s activities.
(iii) Proteins also provide energy (4k calories/gm) in case of carbohydrate-depletion. Carbohydrate-depletion takes place during starvation or prolonged exercise session. However, foods rich in proteins are often expensive and we should not waste them as fuel for energy. Proteins are primarily meant for building and maintenance of the body; carbohydrates and fats are preferred fuel for energy.

More protein – more muscles?

More protein does not lead to more muscles. In our body, proteins exist in a dynamic state. They are continually broken down and replaced by new proteins. This continued replacement is known as ‘protein turnover rate’. Increased physical training, severe illness, hard manual labour etc. increase protein turnover rate. Thus, demand for more proteins arises from within the body. It is not possible to increase the body’s protein metabolism artificially and thereby stimulate muscle growth simply by eating more amount of protein. Therefore, you should be careful of the advertisements of high-protein diets claiming to give you a bodybuilder’s body without doing any exercises. You might be really pumping your money to the shopkeeper’s pocket by eating so much of protein-supplements!

How much proteins do we need?

(i) The RDA (Recommended Dietary Allowance) for proteins in adults is .8 gm per kg/body weight per day. If one weighs 70 kg, his daily proteins requirement will be 70 x .8 =56 gm.
(ii) Those who are involved in exercise of high intensity and high volume may benefit by taking proteins well above the RDA (1.2-2 gm/kg body weight/day). Studies show that protein intake beyond 2 gm/kg body weight is not desirable.
(iii) Normally, caloric intake from proteins should be 15-20% of the total caloric intake. If one’s daily total caloric intake is 3000 Kcalories, 450-600 Kcalories should come from proteins. Rest of the calories should come from carbohydrates and fats.
(iv) Depending upon the nature, intensity and volume of work/ exercise, there can be minor variations in proportion of calories from three major nutrients (i.e., proteins, carbohydrates and fats). For the athletes engaged in strength exercises, 20% of calories may come from proteins, 60% from carbohydrates and 20% from fats. On the other hand, in case of endurance athletes the proportion of carbohydrates may go up to 70%, thereby reducing the caloric percentage from proteins and fats.
(v) If there is decrease in total caloric intake for any reason (e.g., in case of someone trying to lose weight by reducing the total caloric intake) he should raise the percentage of caloric intake from proteins above 15% to avoid loss of lean body mass. Lean body mass is the body mass minus fat. The main reason for this is that our major energy requirement should be met from carbohydrates and proteins should be spared for building and maintenance of the body. Proteins are used for energy, only under the extreme conditions, as mentioned earlier. Therefore, if carbohydrate-depletion is a deliberate act and proteins are intended to be used as fuel, total percentage of protein intake will have to be increased above the RDA.

What happens to surplus protein?

(i) If dietary protein’s intake is more than our requirement, it can be utilized by our body for energy or simply converted to fat for future use.
(ii) Many of the high-protein diets are high in fat also (e.g., animal foods have large amount of saturated fat and cholesterol). This is a health risk factor.
(iii) High-protein diets are often low in fibre. This hampers smooth food movement inside on body and overloads digestive system leading to constipation.
(iv) Studies have found that high-protein diet can even cause too much loss of calcium through urine. Those who take high-protein diet should also take high doses of calcium to avoid osteoporosis over a period of time.
(v) Excess protein is not good for kidneys. The kidneys would have to process more nitrogenous wastes which are generated during protein metabolism. This overload on kidneys may ultimately lead to kidney disease.
(vi) High-protein diets are also more dehydrating. Removal of nitrogenous wastes by kidneys is done through increased fluid excretion causing fluid loss. Dehydration often leads to poor physical and mental performance.
Essential and non-essential amino acids

Amino acids are building blocks of proteins. There are approximately 22 different amino acids. Ideally, our food should provide all amino acids. The body itself can synthesize some amino acids from carbohydrates (these are called non-essential amino acids). But there are nine amino acids which cannot be synthesized by the body and we have to obtain them from our dietary protein (these are called essential amino acids).

Dietary proteins that contain all amino acids (both essential and non-essential amino acids) are known as ‘complete proteins’. The complete proteins are generally found in foods of animal sources, i.e., meat, dairy products, eggs, fish, etc. Contrary to this, dietary proteins that do not contain all the amino acids are called ‘incomplete proteins’. These are generally of plant origin, e.g., nuts, grains, legumes, seeds, etc.

However, vegetarians need not get alarmed by this. By ‘mutual supplementation’ two or more vegetable proteins can be mixed together to compensate for each other’s individual deficiency of all amino acids. For example, soy beans, peas, beans, lentils, legumes can be mixed with rice, wheat, corn etc. This way vegetarian proteins can be as good (and as complete) as non-vegetarian proteins.

Back to top >

III. CARBOHYDRATES

Introduction The main function of carbohydrates is to supply energy. Though carbohydrates provide approximately equal amount of energy as proteins (4Kcalories/gm), they are far more efficient fuel than proteins.
Dietary carbohydrates are of two types – simple and complex. Simple carbohydrates are made up of one or two sugar molecules (e.g., honey, jelly, soft drinks, etc.). Complex carbohydrates contain many sugar molecules linked together. (e.g., whole grains, potatoes, vegetables and fruits, etc.).

How much carbohydrates should we take?
(i) As per the RDA, (Recommended Dietary Allowance) our daily carbohydrates intake should be within range of 6-11 gm/kg of bodyweight. If a person weighs 70 kg, he should take 420-770gms of carbohydrates depending upon his daily caloric requirement. A 70-kg marathoner will require more caloric intake (and, thereby, proportionately more carbohydrates) than a 70-kg sedentary clerk.
(ii) 55-60% of our total dietary calories should come from carbohydrates. If a person’s daily caloric intake is 3000 calories, 1650-1800 calories should come from carbohydrates.
(iii) Carbohydrates are a preferred metabolic fuel. They spare proteins for muscle building and maintenance of body. If our intake of Carbohydrates is less than the RDA, our body may tend to utilize proteins for energy and consequently muscle building may suffer.
(iv) Low carbohydrate diet will build up low glycogen stores in the muscles. Thus, chronically deplete muscle glycogen stores may lead a person to reduced performance. Those on ‘crash diet’ should note this.

Digestion of carbohydrates

Digestion of carbohydrates starts in mouth. While chewing of food (mastication) we produce saliva. Salivary enzyme amylase breaks down the starch(which is tasteless) of carbohydrate to maltose which is sweet. This is why food tastes sweet if properly chewed.

Chewing our food well helps better digestion and optimal utilization of food intake. Yoga teachers recommend to ‘drink the food’ (chew the food so long that it becomes liquid in your mouth, then swallow it) for its best utilization. Chewing well also discourages overeating. (The task itself is so boring that naturally you will not have much patience to take huge dose of food !)

Complex vs simple carbohydrates

Complex carbohydrates are preferable to simple carbohydrates for these reasons –

(i) Complex carbohydrates contain fibre, water, vitamins and other nutrients. Simple carbohydrates on the other hand, have hardly any other nutrients.
(ii) The presence of fibres in whole-grain food makes them more satisfying. Foods rich in fibre prevent constipation.
(iii) High-fibre foods, also take more calories for their digestion. This has an important implication for weight control. One can eat high-fibre foods to his satisfaction and still may not gain much weight!
(iv) Complex carbohydrates encourage better glycogen storage than simple sugars.

Carbohydrates loading (carbo-loading)

Carbo-loading is a practice prevalent among endurance athletes. This technique is used to enhance muscle glycogen store of the athlete prior to the race. Firstly, the athlete eats low-carbohydrates diet for 3 days and simultaneously has prolonged exercise sessions of high-intensity to deplete his body of the carbohydrates to a great extent. This is followed by 3 days of rest or very low-intensity exercise and simultaneously a high-carbohydrates diet. During these 3 days, a ‘carbo-starved’ body tends to store more muscle glycogen than its normal level (super-compensation effect). This increased level of glycogen store helps the athlete to perform for a longer time. ‘Hitting the wall’ is an experience that occurs to runners during long distance runs (e.g., during marathon) when marathoner’s body is so depleted of carbohydrates that he seems to ‘hit the wall’ and has hardly any energy left in him to carry forward. Carbo-loading pushes the ‘wall’ further towards the finishing line. (If earlier you hit the wall at 30th km, now you may experience it, may be, at 40th km.)

However, this technique does not suit everyone. Sometimes carbo-loading in its carbo-depletion stage causes undesirable side effects, e.g., physical and mental fatigue, depression and irritability. Never try this at the time of race unless you have done so during your training.

Tips to make the most out of carbohydrates:

(i) Carbohydrates are best absorbed if taken immediately after the exercise. Why? A prolonged, intense exercise causes carbohydrates- depletion in our body. The muscle glycogen level requires to be restored soon after the exercise. If carbohydrates are not ingested within half an hour or so, our body turns to utilize its proteins for energy requirement. As mentioned earlier, proteins are primarily meant for body building and not for supplying energy. If they are diverted to be used as fuel, muscle building will take a back seat.
(ii) What’s the best type of carbohydrates for instant refuelling after exercise? A natural choice will be those carbohydrates that figure high on glycemic index. (Glycemic index is a scale that describes how fast a food is converted to glucose in the blood). However, in some cases, taking too much of high glycemic carbohydrates may elevate blood-sugar level. This may stimulate sudden spurt of insulin which may cause abnormal fall in the blood-sugar level (hypoglycemia). Due to temporary hypoglycemia, one may feel weak or dizzy. Therefore, it is advised to have a wise combination of both high and low glycemic foods.

Most fruits and vegetables, whole grain breads, milk, dals are low glycemic Index foods. Cornflakes, potatoes, watermelon, white bread, sugar, honey are high foods.


Back to top >

IV. FATS

Introduction

Fats are not as bad as most of us are made to believe. On the contrary, they are useful in many ways -

(i) They help in absorption of fat- soluble vitamins, i.e., vitamin A, vitamin D, vitamin E and vitamin K. Vitamin A is required for growth and repair of tissues, maintenance of proper vision, resistance to infection; Vitamin D is required for bones and teeth; Vitamin E helps in the muscle tissue/repair process; Vitamin K is required in the process of blood clotting, protein formation and also for healthy bones.
(ii) Fats provide energy.
(iii) Let’s be honest about it, fats make our food tasty.
(iv) Essential fats (those fats which our body cannot make; therefore, we have to get them from food) are required for our normal growth, healthy arteries and nerves, for smooth skin and healthy joints. They also help in cholesterol metabolism. Corn, soybean, safflower oils are very high in essential fats. Nuts, seeds are also very important source of essential fats.
(v) Studies have shown that Omega-3 fatty acids (found mainly in fish as well as in green leafy vegetables, nuts) are helpful for the patients of heart disease and high blood pressure. They help to make high density lipoprotein (HDL) and regulate production of low density lipoprotein (LDL).
(vi) Fats regulate sex hormones.
(vii) Fats are necessary for healthy cells.

How much fat is enough?

(i) American Heart Association (AHA) recommends that in our daily diet not more than 30% of total calories should come from fat. However, in case of bodybuilders, athletes, who have to carry more muscle mass than fat in their body composition for peak performance, fat may come form 15-20% of their total calories. For a normal person 20% dietary fat is enough.
(ii) Saturated fats should contribute not more than 30% of the total calories from fats.
(iii) However, by reducing fat intake less than 15-30%of total dietary calories you risk trouble in absorption of fat-soluble vitamins (vitamins A, D, E, K).

Saturated, unsaturated and trans fats

The classification of fats is based on the saturation of their chemical bonds by hydrogen. In saturated fatty acids most of the chemical bonds are occupied by hydrogen. Unsaturated fats have fewer of these bonds occupied by hydrogen.

Animal fats are available in meat, egg, milk and milk products. These fats are predominantly saturated and associated with heart disease. Therefore, their consumption should be limited. Vegetable fats are predominantly unsaturated. Unsaturated fats are mostly liquid at room temperature (e.g., vegetable oils). Saturated fats are mostly solid at room temperature. However, coconut oil is an exception, which is saturated but exists as a liquid at room temperature. Trans fats are produced when liquid fat is made solid by a process called hydrogenation. Trans fats act like saturated fats and can pose the same health risks. Many of the processed foods like potato chips, samosa, bakery items (cakes, muffins, cookies, etc.), french fries contain trans fats.

Why excess dietary fat is not good for you:

When we count the fat intake in our diet, we should not overlook the hidden fat. For example, while munching deep fried peanuts we should not forget that in addition to the oil used for cooking, the peanuts themselves contain huge amount of fats.

These are some inherent health risks involved with high-fat diet –

(i) There is a relationship between dietary fat (especially saturated fat), blood cholesterol level and risk of heart disease. The risk of colon cancer is also associated with high-fat diet.
(ii) Unsaturated fats contribute to production of free radicals which are associated with aging and certain degenerative diseases.
(iii) Fat has less thermic effect. This means that fewer calories are required to convert dietary fat into body fat. This contributes to weight gain.
(iv) Fat is a high-energy source. (Protein/carbohydrates4 kcalories/gm; fat9 kcalories/gm). It satisfies appetite very readily and is stored in body very easily. This may discourage one to take balanced food if his hunger is already satisfied.

Cholesterol

Cholesterol is a waxy, light-coloured substance. It comes in two different forms- cholesterol in food and cholesterol in blood. Our dietary cholesterol intake should not exceed 300mg/day. Food cholesterol is mainly found in foods of animal origin (meat, dairy products). Plant foods do not contain any cholesterol. Foods like liver, eggs, beef, pork, chicken, milk are high in cholesterol.

Our liver manufactures blood cholesterol from saturated fats. This means that the more saturated fat we take the more cholesterol our liver will make. The excess circulation of cholesterol in blood can accumulate on the inner walls of the arteries (called plaque) leading to heart disease. Cholesterol may be present in blood as a constituent of Low Density Lipoprotein (LDL) or of High Density Lipoprotein (HDL). LDL and HDL affect heart disease risk differently. LDL is known as bad cholesterol. It is responsible for depositing cholesterol on the artery walls. HDL is good cholesterol. It contains smaller amount of cholesterol. Its job is to remove cholesterol from the cells in the artery walls and transport it back to the liver for reprocessing .

Back to top >

V. VITAMINS AND MINERALS

Introduction

Vitamins and minerals are referred to as micronutrients. Unlike macronutrients (i.e., proteins, carbohydrates and fats) they do not directly supply energy. But they help in the metabolism of macronutrients.

Vitamins
Vitamins are organic substances. They cannot be synthesized by our body. Therefore, they are to be obtained from our diet.

Vitamins are classified according to their solubility in fat or water. There are four fat-soluble vitamins – vitamins A, D, E and K. They are absorbed with dietary fats and can be stored to some extent in our body.

Water-soluble vitamins are – vitamin C, B1, B2, B6, B12, niacin, folic acid etc. Unlike fat soluble vitamins, these vitamins are not normally stored in the body. Therefore, we have to take them daily. Symptoms of water-soluble vitamins deficiency may be apparent in 6-7 days.

How much vitamins do we require?

One of the most frequently asked questions is whether one requires vitamins supplements. The answer is – generally, there is no cause of worry about vitamins deficiency if one is on a nutritionally balanced diet. This applies to athletes also.

However, in case of very intense/high-volume exercise, one may require to take vitamin/mineral supplementation. Studies have shown that heavy exercise may reduce vitamin/mineral status in the body. This generally happens in case of vitamin C and riboflavin (B2). Stressful situations may increase the need for vitamins and minerals too. But one should remember that generally the increased requirement for vitamins and minerals can be met by proportionately increasing total amount of diet.

Sometimes, high doses of vitamins may produce a temporary feeling of improved performance. But remember that vitamins taken in abnormally high doses, are no longer working as vitamins only; possibly they are acting like performance-enhancing drugs.

Functions of major vitamins and their food sources are given in the table below –

Vitamins	Functions	Best Food Sources
Vitamin A	Normal vision, growth and repair of body tissues	Liver, egg yolk, whole milk, butter, carrot, ghee, papaya, green leafy vegetables.
Vitamin D	Helps in absorption of calcium and building of bone mass.	Fish, milk, egg yolks, butter and sunlight.
Vitamin E	Helps in repairs of exercise- induced tissue damage	Nuts, seeds, wheat germ, polyunsaturated vegetable oils, fish liver oils, peanut butter
Vitamin K	For normal blood clotting, bone formation	Vegetables, milk.
Vitamin C	Helps iron absorption, protects against infections.	Amla, Citrus fruits and green leafy vegetables, lemon juice, potatoes.
Vitamin B- Complex	Metabolism of carbohydrates, proteins, fats, healthy nervous system, normal growth.	Rice, wheat, animal foods, nuts, peanuts, soybean, leafy vegetables, fruits, beans.

Minerals

Minerals are inorganic elements constituting approximately 3-4% of our body weight. These are generally divided into two categories – (i) Trace elements – these minerals are present in very small quantities, i.e., less than .01% of body weight; (ii) Macrominerals – they are more then .01% of body weight. Both are equally important for our body and their deficiency may have major health implications. The macrominerals include sodium, calcium, phosphorus, magnesium, potassium, sulphur. Important trace elements are iron, zinc, selenium, iodine. We will discuss about some important minerals.

Sodium

Sodium maintains normal water balance within our body, affects blood pressure, maintains acid-base balance and muscular contraction. The major sources of sodium are common salt (Sodium Chloride) and MSG (Monosodium Glutamate). One tea spoon of salt (approx. 5 gm) has approximately 2000-2200 milligram of sodium. Sodium is naturally found in majority of the foods. The recommended sodium intake is around 500-2400 mg a day (i.e. not more than approximately 1¼ tea spoon). Most of us eat more salt and thus take more sodium than we actually need. This will be evident when we notice the ‘hidden salt’ in our foods – both natural as well as processed. Junk foods are bad due to their high salt contents also.

Excess sodium intake can cause water retention in our body which may result into undesirable weight gain. Don’t be surprised if one fine morning your weighing machine suddenly shows a weight gain of 200-400 gm. In all probability, the culprit may be just the small salty pickle you ate previous night! Secondly, high salt intake may increase the risk of high blood pressure. Thirdly, too much of salt is bad for our kidneys.

There are two myths associated with salt – (i) one requires more salt while doing vigorous and prolonged exercise, and (ii) cramps can be avoided (especially during distance running), if salt intake is increased. The fact is that actual loss of salt through sweat is not very significant. If we look at our daily amount of salt intake, we will find that our daily intake of salt is enough for running a marathon per day! Secondly, the studies have yet to find any substantive relationship between muscle cramps and salt deficiency.

Calcium

Calcium and Phosphorous are major constituents of our bones and teeth. Every day some amount of calcium from the bones circulates in the blood. This removed amount of bone calcium is quickly replaced by calcium from our diet. If the dietary calcium is not adequate, the lost bone calcium cannot be fully replaced. Calcium deficiency may thus lead to inadequate bone calcification and subsequently to osteoporosis. Dairy products are major sources of calcium. Therefore, those who avoid intake of dairy products in their diet (for fear of weight gain) are at a greater risk.

Increasing calcium content of diet may be useful to prevent osteoporosis. Physical exercise, particularly weight training, may also help prevent and reverse osteoporosis. Weight training increases the density of bones by stressing them. Therefore, the best way to prevent osteoporosis will be to combine both exercise and diet.

There is a word of caution for those who are engaged in long-distance running. Their diet may not be adequate enough to provide sufficient calcium for replacement of lost bone calcium. In their cases, prolonged exercise may lead to bone-thinning instead of bone-strengthening. Such athletes should seek medical advice to increase their calcium intake accordingly.

Iron

Iron deficiency is found to be common among athletes, especially, those involved in prolonged physical activities (e.g., long-distance running). This deficiency may be due to inadequate absorption of dietary iron, losses from gastrointestinal tract, or excessive sweating.

The RDA for iron is 10 mg/day for men and 15 mg/per day for women. Women require more iron than men because of iron losses during their menstruation.

Since iron is necessary for carrying oxygen to muscles, iron deficiency may lead to less oxygen supply to muscles. This deficiency may result into extreme fatigue, loss of strength and endurance, and prolonged recovery periods after an exercise.

Iron is found in two forms. Heme iron (in animal foods, e. g., meat, liver, poultry, fish) is readily absorbed iron. Non-heme iron (in vegetables) is less absorbed. Your body is not able to absorb all iron present in the vegetables. However, there are certain food items that help in more absorption of non-heme iron, e. g., foods rich in Vitamin C. Add some fruit or a glass of fruit juice, or salad to your diet, or simply sprinkle some lemon juice for better absorption of iron from vegetables.

Coffee and tea tend to inhibit the absorption of iron. Hence, these beverages should be taken 1-2 hrs. after the meal.

On the other hand, excess iron intake has its own harmful implications. It tends to cause indigestion and constipation. In its extreme form excess iron intake may lead to hemochromatoris, in which the body stores excess iron in heart and liver tissue.

Functions of important minerals and their food sources are given in the following table –

Mineral	Function	Best Food Sources
A. Major Minerals Calcium	Healthy bones, teeth, muscle contraction.	Dairy products, green leafy vegetables, Ragi.
Phosphorous	Strong bones and teeth.	Animal foods, whole grains, nuts.
Magnesium	Metabolism of carbohydrates and proteins.	Whole grains, nuts, green vegetables.
Potassium	Maintenance of normal fluid balance of cells, muscle contraction.	Potatoes, vegetables, fruits, banana.
Sodium	Maintenance of normal fluid balance of cells, Nerve and muscle function.	In almost all foods
B. Trace Iron	Red blood cell formation, oxygen transport to cells.	Green leafy vegetable, liver, meats, nuts, beans.
Iodine	Regulation of growth, development, energy metabolism.	Iodized salt.

Back to top >

VI. WATER

Importance of water

By weight, water constitutes approximately 45-60% of human body. Water provides a medium for biochemical reactions as well as transport and exchange of nutrients, metabolic by-products, gases and heat. Therefore, any small change in water content in our body may cause changes in biochemical reaction dependent on water. Acute water loss, i.e., dehydration may bring many health complications.

Sufficient water intake is necessary for healthy kidneys. Inadequate water intake increases concentration of urine and thus contributes to stones formation as well as growth of germs infections. The best way to avoid these complications is to keep urine sufficiently dilute by drinking sufficient water throughout the day.

One body loses water through perspiration and respiration. Depending upon intensity and duration of exercise or outside temperature, a person may lose between 1-3 litres of water per hour (i.e., approximately 1-3 kg of body weight). Any intense exercise beyond one hour will thus interfere with cooling function of the body and will affect a person’s performance. A marathon runner may lose even upto 4.5 litres of water during 2½-3 hrs. of race. This loss cannot be compensated during the race and there will be a huge deficit of water intake. It is, therefore, important to hydrate one’s body before, during and after any prolonged exercise.

Guidelines for adequate hydration:

(i) Don’t wait for thirst. The feeling of thirst lags behind your body’s need for water. Therefore, without waiting for thirst, drink sufficient amount of water in a day. The colour of your urine is a good indicator of your body’s hydration. It should always be clear or pale; if it is yellowish, it may be indicative of under-hydration.
(ii) Cold water (4-5 0C) is absorbed faster in your system. However, during cold day warm water will make you more comfortable.
(iii) On higher altitudes, where it is dry, drink more water.
(iv) Avoid coffee, tea, cola, alcohol. These are diuretics (diuretics cause the body to eliminate water and thus dehydrate it). It is a good idea to drink a glass of water before drinking tea or coffee.
(v) During an exercise of a longer duration (beyond 1 hour), drink (100-150 ml) every 15-20 minutes. But never ‘over drink’.
(vi) Sugar-and-electrolyte solutions can be taken during prolonged exercise, but they should be sufficiently diluted. It should be a hypotonic solution with a lower osmotic pressure than that of body’s fluids. If the solution is too concentrated, it will not be absorbed by the body and can lead to gastric distress. Taking glucose in dry powder form is not a good practice.

Hyponatremia (water intoxication)

It is good to hydrate oneself at regular intervals during an exercise of long duration. But too much of water intake has its own hazards. Over drinking may lead to hyponatremia (loss of sodium). This happens as too much of water ingestion dilutes sodium contents in blood. Acute sodium-deficiency may result into heat exhaustion and cardiovascular collapse.

Summary of the chapter –

Nothing is as confusing as the subject of nutrition. Don’t get confused. Be practical. Eat whatever you have been eating and enjoying so far. Just keep following points in your mind regarding your diet –

(i) Proportion of daily calories should approximately follow this formula – 60% from carbohydrates, 20% from protein and 20% from fats.
(ii) Avoid processed, tinned food (which are high in sugar, salts and low in fibres). Prefer natural, seasonal, fresh, fibrous food.
(iii) Follow Food Guide Pyramid.
(iv) Reduce your salt intake. Excess salt adds to high blood pressure. It also adds to overall body weight by retaining more water in body.
(v) Include nuts in your diet.
(vi) Eat sprouts of Bengal gram, moong, soybeans,etc. They are filled with enzymes, protein, complex carbohydrates, fibre, vitamin and minerals. Sprouts also contain antioxidants and protect us from the ongoing effects of aging.
(vii) Cut down on sugar.
(viii) Cut down on saturated fats. Prefer low fat diet.
(ix) Avoid overeating. Eat 4-5 small meals instead throughout the day.
(x) Be happy while eating your food.

Medical disclaimer - The website content is provided for general educational purpose only. It does not substitute professional medical advice. Reader is advised to consult his doctor before starting any fitness program to avoid any health risks.