Due to the intensity of subject 1’s weekly calorie needs (4 hours of football), the 57% of carbohydrate content needs to probably exceed the 60% guideline to maintain a high level of performance.
Subject 2
Subject 2 has a bodyweight of 50 kg, so BMR = 50(kg) x 24 (hours) = 1200 Kcal
For the week:
1200 x 7 = 8400 Kcal
The PAR for subject 2 is:
Activity Duration Kcal / min Total
Walking 100 mins 4.1 410
Cleaning 240 mins 3.1 744
Football 90 mins 6.1 549
Walking 120 mins 4.1 492
2195
BMR + PAR = 10595
Therefore calorie needs for each day:
10595 / 7 = 1514 Kcal
By adding the amount of Kcal in the diet together for each day we get 7709.9 Kcal for an average day.
Kcal = total calories for week / 7 (days)
= 7709.9 / 7
= 1101.4 Kcal
The amounts for the remaining nutrients are:
total for week = 898.13
for a daily amount: 898.13 / 7 = 128.3g
To convert this amount in grams to calories:
128.3 x 3.75 = 481.25
To express this as a percentage:
481.25 / 1101.4 x 100 = 44% carbohydrates
total for week = 284
for a daily amount: 284 / 7 = 40.6g
As a calorie amount:
40.6 x 4 = 162.4 Kcal
As a percentage:
162.4 / 1101.4 x 100 = 15% proteins
total amount for week = 248.354g
for a daily amount: 248.354 / 7 = 35.5g
As a calorie amount:
35.5 x 9 = 319.5 Kcal
As a percentage:
319.5 / 1101.4 x 100 = 29%
In assessing each nutrient, the need for carbohydrates if BMR / PAR is taken into consideration:
- carbohydrates = 60% of diet,
So: 60 x (BMR +PAR) = 60 x 1514 / 100 = 908.4 Kcal
So: 25 x 1514 / 100 = 378.5 Kcal
so: 15 x 1514 / 100 = 227.1 Kcal
If we compare these amounts, we can see that per week:
ideal intake = 908.4 Kcal
actual intake = 898.13 Kcal
ideal intake = 378.5 Kcal
actual intake = 248.354 Kcal
ideal intake = 227.1 Kcal
actual intake = 284 Kcal
Subject 2 needs 1514 kcal but is only eating 1101 kcal, in accordance with the amount of training undertaken by subject 2 there needs to be higher calorie consumption. There are too many meals of refined, simple carbohydrates (a daily consumption of chocolate bars is evident), these simple carbohydrates have a relatively low energy content and usually a high fat content, what energy these provide is quickly burned therefore not providing the sustained release of energy that complex carbohydrates would provide (wholemeal pasta, wholemeal bread, cereals).
Subject 2 needs to consume more vegetables; only on Sunday is there any substantial meal with the vitamins that vegetables provide (peas and bean shoots). There are a few high protein meals such as chicken, good because of the low fat content in its white meat, and low fat content. These high protein meals could be supplemented with beans/pulses perhaps, providing a serving of carbohydrates as well as another healthy serving of protein.
Overall the diet of subject 2 needs particular supervision in its high content of sugars and refined foods such as chocolate bars, and its low content of complex carbohydrates – there is only rice, that being white not the advised wholemeal, that provides any real serving of complex carbohydrates. The amount of water consumption is low, with the preference towards fizzy, caffeinated, high sugar drinks such as fanta and coke. Subject 2, in relation to their activity ratio should be drinking at least 1.5 litres of water each day.
Subject 3
Subject 3 has a BMR of: 50 x 24 = 1200
and has a PAR of:
Activity Duration Kcal / min Total
sailing 180 mins 7.9 1422
football 180 mins 7.9 1422
football 90 mins 7.9 711
yoga 60 mins 3.1 186
walking 360 mins 4 1440
5181
BMR + PAR = 1200 + 5181 = 6381 Kcal / week
per day: 6381 / 7 = 912 Kcal / day
Subject three therefore needs a daily consumption of approx. 912 kcal/day
Comparing this to the actual average calorie of subject 3’s diet for the week:
9819 / 7 = 1403 Kcal
This is, of course, higher than the need according to subject 3’s BMR and PAR, this would indicate that there is a risk of weight gain if the calorie intake is not monitored, or the exercise ratio is not increased.
As for nutrient content:
- As carbohydrates should be 60% of the daily intake, we can compare this to subject 3`s actual intake
9819 / 7 = 1403 kcal (average actual calorie intake/day)
Of this amount:
Carbohydrates should be approx. 547 kcal per day or 146g (547 / 3.75)
The actual amount is an average of
833 kcal per day or 223 g (833 / 3.75)
As fat should be approx. 25%:
The calorie intake should be approx.228 kcal per day or 25g (228 / 9)
The actual amount is an average of
423 kcal per day or 47g
As protein should be approx. 15%:
The calorie intake should be approx. 137 kcal per day or 34g (137 / 4)
The actual amount is an average of 172 kcal per day or 43g (172 / 4)
As we can see these amounts of actual intake are considerably higher than the perceived guideline for the intake of nutrients, this would mean that there needs to be serious revision of the diet for subject 3, in order to maintain a healthy body and to maintain a stable body weight considering the high calorie intake.
Once again we see that subject 3`s diet contains considerable quantities of simple sugars and simple carbohydrates, foods such as what seems like a daily consumption of mars bars, as well as other chocolates. This is not part of a stable healthy diet; these sugars are used by the body quickly and upset the homeostasis of the body with a high burst of sugar that the body counters with the release of insulin. If the consumption of these simple sugars in the form of sweets is prolonged, the risk of sugar related illness such as diabetes in the extreme cases is greatly increased.
As far as other nutrients are concerned, on the plus side there is quite a high consumption of fruits such as bananas and apples, providing essential vitamins as well as a sustained energy release. Ignoring the simple, sugary snacks, there is a basis for a relatively healthy diet, with some complex carbohydrates being consumed such as jacket potatoes, baked beans – also a good source of protein, and pasta – although not wholemeal, a good enough source of carbohydrates nonetheless.
The liquid consumption again needs monitoring, with the high activity ratio of subject 3 the intake of water needs to be a minimum of 1.5 litres a day, ideally in excess of this amount in order to stop dehydration and to optimise ATP production for exercise.
Subject 4
BMR: 87 x 24 = 2088
for a week: 2088 x 7 = 14616 Kcal / week
PAR:
Activity Duration Kcal / min Total
football 240 mins 13.5 3240
walking 200 mins 6.9 1380
4620
BMR + PAR = 14616 + 4620 = 192.36 Kcal / week
so: 192.36 / 7 = 2748 Kcal / day
This gives an ideal intake for the following nutrients:
- carbohydrates: 60% x 2748 / 100 = 1649 Kcal
- protein: 15% x 2748 / 100 = 412 Kcal
- fat: 25% x 2748 / 100 = 687 Kcal
By assessing each day and adding all the nutrients separately, the results are:
total per week = 1384g / week
per day: 1384 / 7 = 198g
as an expression of calories: 198 x 3.75 = 742 Kcal
to find this calorie as a percentage:
742 / total Kcal for day = 742 / 1549 x 100 = 48%
= 48% carbohydrate content of diet
total per week = 749g/ week
per day: 749 / 7 = 107g
therefore, as calories: 107 x 4 = 428 Kcal
as a percentage of diet: 428 / 1549 x 100 = 28%
= 28% protein content of diet
total per week = 286g / week
per day: 286 / 7 = 41g
so, as calories: 41 x 9 = 368 Kcal
as a percentage of diet: 368 / 1549 x 100 = 24%
= 24% fat content of diet
The diet of subject 4 is slightly lower in carbohydrates than the guidelines suggest, although this is balanced by the low intensity and amount of activity, thus eliminating the needs for large stores of carbohydrates that would otherwise be needed for a more intense regime. There is a large consumption of protein in the diet, this, unlike carbohydrates is not stored in the muscles so cannot be stored as fat.
The intake of fat in the diet is almost the same as the guideline amount(24% as compared to the guideline 25%).
The importance of nutrients to athletes
Calories
Calorie needs are high during periods of growth and gradually decrease after 30 years of age. A combination of high physical activity with rapid growth dramatically increases calorie needs. The decreased calorie needs and physical activity that tend to occur with ageing often result in weight gain. The calorie needs for athletic performance depends on the type of athletic event, intensity, duration, and frequency performed. Individuals participating in vigorous physical training can have calorie needs ranging from 2,000 to 6,000 calories per day.
Carbohydrate
In general 60%of calories should come from carbohydrate. A high carbohydrate diet increases muscle glycogen stores. Muscle glycogen stores provide an energy reserve, resulting in greater endurance and delayed fatigue. For long duration athletic competitions (events longer than 90 minutes), maximising muscle glycogen stores is achieved by a modified carbohydrate loading plan which consists of a very high carbohydrate diet three days prior to the event and a week of reduced workouts, and resting the day prior to the athletic event. The modified carbohydrate loading plan is recommended over the original carbohydrate loading plan which involved a carbohydrate depletion period, and resulted in decreased ability to train before the event and possible health risks.
Protein
The Recommended Dietary Allowance (RDA) for protein for the general adult is 0.8 gm per kilogram body weight. Athletes may require more protein than the adult RDA, but the increased requirement appears to be small.
A protein intake of 1.0 to 1.5 gm proteins per kilogram body weight may be recommended for competitive athletes. Even this higher protein intake level can be easily met through a balanced diet including a variety of foods. The use of amino acid and protein supplements is not necessary, nor do they contribute to athletic performance or increased muscle mass. In fact, amino acid or protein supplements can be harmful to athletic performance, by increasing dehydration risks. Protein beyond required amounts is stored as fat, this requires that breakdown products from protein metabolism are excreted in the urine resulting in water loss and increased risk of dehydration.
Fat
Fat intake should not exceed 30% of calories. In determining the distribution of calories for an athlete, carbohydrate and protein needs are calculated first, and then fat is used to provide the additional calories, but not to exceed 30%.
Vitamins and Minerals
Vitamins and minerals play an important function in carbohydrate, protein and fat metabolism, and in muscle function. While physical activity may increase the need for some vitamins and minerals, the increased need can be met by consuming a well-balanced diet, high in carbohydrate, moderate in protein, and low in fat. Only individuals who consume low calorie diets are at risk for having a low vitamin and/or mineral intake. The increased calories athletes need for physical activity will provide the additional vitamins and minerals needed if a wide variety of foods and a well-balanced diet are consumed. There is no evidence that athletes consuming a well-balanced diet need vitamin and/or mineral supplements, nor that vitamin and/or mineral supplements will improve athletic performance.
Iron and calcium are two minerals that are especially important for young athletes, especially women. Iron is part of haemoglobin and myoglobin, which are essential for oxidation to occur. If iron deficiency occurs then athletic performance is hindered. Athletes should be screened periodically to evaluate their iron status. A temporary condition called "Sports anaemia" is sometimes experienced by athletes due to an increase in blood volume associated with initial training; however this condition does not affect athletic performance.
Low body fat levels and high physical activity, such as gymnastics, swimming and long-distance running, may decrease bone development in young female athletes at a time when maximum bone formation should occur. This condition is called "amenorrhea." Amenorrhea can increase the risk of stress fractures and hinder athletic performance. If amenorrhea is present, increased calcium intake to 120% of the calcium R.D.A helps bones to develop properly and maintain bone density.
Fluids and Hydration
Increased muscle activity results in increased heat production in the body. The body's main way of removing heat is by producing sweat. Sweating can lead to dehydration which can have an adverse effect on muscle strength, endurance, co-ordination and increase the risk of cramps, heat exhaustion, and heat stroke which can result in death.
To prevent dehydration, water must be replaced. Some athletes can loose 6 to 8 lbs. of body fluid per hour of strenuous physical activity. To make sure adequate body fluid is replace, body weight is measured before and after athletic sessions. One pint or 16 oz of fluid is needed to replace each pound lost. If the next day body weight is not within 1 to 2 pounds of the previous day's pre-athletic activity additional fluids should be consumed before exercising.
Guidelines for fluid intake are 2 cups fluid about 2 hours before the athletic event, an additional 2 cups fluid 15 to 20 minutes before the event. In hot and humid conditions, frequent small (4 - 6 oz) servings of plain cool water are recommended. Thirst is not a good indicator of fluid need because vigorous physical activity can delay the thirst mechanism.
For most individuals cool water may to replace fluids after exercising for 1 hour or less. The typical American diet provides sufficient sodium and other minerals lost in perspiration. Exercise over 1 hour, or in high temperature/humidity conditions may warrant use of sports beverages as part of re-hydration. Sports drinks with 6% to 8% glucose, glucose polymer, or sucrose with a small amount of sodium are quickly absorbed and help maintain blood glucose levels during athletic events without causing stomach distress. Fructose as the carbohydrate source may cause stomach distress and require more time before it can be used by the muscles for energy because it must first be converted into glucose.
Sports drinks – Isotonic/hypertonic/hypotonic
Depletion of the body's carbohydrate stores and dehydration are two factors that will limit prolonged exercise.
Sweating is the way in which the body maintains its core temperature at 37 degrees centigrade. This results in the loss of body fluid and electrolytes (minerals such as chloride, calcium, phosphate, magnesium, sodium and potassium) and if unchecked will lead to dehydration and eventually circulatory collapse and heat stroke. The effect of fluid loss on the body is as follows:
Electrolytes serve three general functions in the body:
- many are essential minerals
- they control osmosis of water between body compartments
- they help maintain the acid-base balance required for normal cellular activities
The sweat that evaporates from the skin contains a variety of electrolytes. The electrolyte composition of sweat is variable but comprises of the following components:
- Sodium
- Potassium
- Calcium
- Magnesium
- Chloride
- Bicarbonate
- Phosphate
- Sulphate
There are three types of Sports drink all of which contain various levels of fluid, electrolytes and carbohydrate.
The osmolality of a fluid is a measure of the number of particles in a solution. In a drink these particles will comprise of carbohydrate, electrolytes, sweeteners and preservatives. In blood plasma the particles will comprise of sodium, proteins and glucose. Blood has an osmolality of 280-330mOsm/kg. Drinks with an osmolality of 270-330mOsm/kg are said to be in balance with the body's fluid and are called Isotonic. Hypotonic fluids have fewer particles than blood and Hypertonic have more particles than blood.
Consuming fluids with a low osmolality, e.g. water, results in a fall in the blood plasma osmolality and reduces the drive to drink well before sufficient fluid has been consumed to replace losses.
Isotonic - quickly replaces fluids lost by sweating and supplies a boost of carbohydrate. This drink is the choice for most athletes - middle and long distance running or team sports. Glucose is the body's preferred source of energy therefore it may be appropriate to consume Isotonic drinks where the carbohydrate source is glucose in a concentration of 6% to 8% - e.g. Lucozade Sport.
Hypotonic - quickly replaces fluids lost by sweating . Suitable for athletes who need fluid without the boost of carbohydrate - jockeys and gymnasts.
Hypertonic - used to supplement daily carbohydrate intake normally after exercise to top up muscle glycogen stores. In ultra distance events high levels of energy are required and Hypertonic drinks can be taken during exercise to meet the energy requirements. If used during exercise Hypertonic drinks need to be used in conjunction with Isotonic drinks to replace fluids.
Suggested daily diet plan
Subject 1
Kcal CHO Fat Protein
weetabix x 2 198 43 2 4
s/s milk 250ml 123 13 6 8
wholemeal pasta 355 90 7 8
110g -uncooked
water – 500ml
veg mix 250 25 8 9
(peas/carrots/corn) 60g
banana 50 18 3 3
water – 500ml
chicken curry 200 15 10 14
60g
wholemeal rice 300 60 3 8
85g - uncooked
water – 500ml
water intake approx. 1.5 l
Subject 2
Weetabix mini crunch 141 29 4 2
75g
milk 250ml 123 13 6 8
semi-skimmed
water 500ml
jacket potato 275 60 5 4
100g
b/beans 350 53 8 9
½ tin
water 500ml
apple 45 4 2 3
spaghetti bol. 350 83 7 9
100g w/sauce
lean mince 200 3 9 20
45g
orange juice 50 1 1 2
300ml
water 500ml
daily intake approx. 1.5litres of water.
Subject 3
Fruit&fibre 225 52 3 8
80g
milk 250ml 123 12 5 8
water 550ml
vegetable bake 210 35 10 6
(carrots/onion/peas)
water 550 ml
banana 50 18 3 3
chicken 150 2 2 11
50g
wholemeal rice 200 30 1 2
80g
water 550ml
fluid intake > 1.5 litres
Subject 4
Milk 153 13 6 10
s/s 300ml
weetabix x3 220 73 3 10
water 500ml
chicken w/pasta 275 75 13 74
and vegetables 250g
water 500ml
¾ tin baked beans 350 68 5 23
banana 50 18 3 3
lasagne 225 89 5 27
275g
water 500ml
mixed veg. 150 37 8 10
(peas/carrots/corn)
wholemeal rice 200 60 3 9
80g
water 500ml
fluid intake approx. 1.5litres
Dietary Recommendations For Exercise/Competition
Before Exercise/Competition: Dietary guidelines for before exercise mainly involve adequate carbohydrate and fluid intake for exercise. Two to six hours before and endurance event, a meal consisting of 85 to 200 g complex carbohydrates, low fat and low protein. Avoid foods known to cause stomach or intestinal distress. A liquid meal supplement providing a balance of fluid and nutrients may be helpful for athletes with pre-competition stomach distress.
During Exercise/Competition: Small carbohydrate intakes, about 24 g carbohydrate every 30 minutes during endurance events more than 1 hour may delay fatigue. Athletes should be comfortable with this during practice sessions, because some athletes do not tolerate this well. Some athletes tolerate carbohydrate-containing beverages better.
After Exercise/Competition: Carbohydrate intake after exercise helps to replace muscle glycogen. Muscle is better able to replace glycogen stores when up to 600 g easily digested carbohydrate is consumed within a couple of hours after exercising. Consumption of high-carbohydrate foods, as soon as possible after competition, promotes glycogen storage.
Webliography
Bibliography
Boris, C (1990) Athletic Nutrition, McDonald and Janes, Liverpool
Flux, E (1980) Nutrition for sport, Rivers, London
