Nutrition

 

“Why do we eat?”

We eat to survive, for good health, for energy, to be sociable, as a comfort, through boredom, as a habit!

It is possible to have a high intake of food and still be undernourished because the constituents of the food are not balanced to provide a healthy diet.

For a well balanced diet we need to incorporate the following:­

Constituent
% of daily food intake
Carbohydrates
55-60%
Proteins
15%
Fats
25-30%
Vitamins and minerals
Fibres

Carbohydrates

We require most of our food intake from carbohydrates as this is our main energy source. These are categorised into two groups - Simple (sugars) and Complex (starches). Complex carbohydrates also have minerals, vitamins and fibre. Simple carbohydrates, excluding the natural sugars (e.g. In fruits) - have not.

Some foods contain both complex and simple carbohydrates for example biscuits, however the table below will indicate where to find the main sources of each.

 

Complex Carbohydrates
Simple Carbohydrates
Potatoes Sweets
Rice Jam
Pasta
Soda (i.e. cola)
Bread
White sugar
Cereal (not all)
Honey
Vegetables
Grains
Fruit

 

Gram for gram, all carbohydrates contain the same amount of calories though it is important to mainly eat complex carbohydrates because these take longer for the body to absorb, give us a sustained energy release and therefore keep us fuller for longer, (so hopefully it prevents us from snacking!).

Glycaemic Index

All carbohydrates have an absorption time, this is called the Glycaemic Index (G.I). The Glycaemic Index describes more accurately the effects different foods have on your blood sugar levels and is ranked from 0 to 100. Glucose is said to have a G.I of 100 and would therefore be absorbed immediately into the bloodstream. All foods are absorbed at different rates, the higher the G.I score the more rapidly that specific food will increase our blood sugar levels.

G.I figures are more useful for athletes who need to replenish their muscle cells quickly for example during or immediately after exercise. However, for general fitness training, if you had not eaten for a while and had finished exercising, you may feel slightly fatigued or lacking in energy so a high G.I product such coke would hit your sugar levels straight away making you feel more replenished. (Don’t undo all your good work though by consuming too much sugar!) A medium G.I product (ie. a banana) would be suitable to eat approximately an hour before your training begins so that you do not fatigue too early.

Product

GJ score

Milk
27
Pasta
37
White rice
87
Muesli
56
Dried apricots
31
Orange juice
46
Weetabix
69
Baked potato
85

When should I eat?

Ideally it is best to have eaten between 2 and 4 hours before you begin exercising so you have time to digest the food. This ‘meal’ should primarily consist of carbohydrates and have a low to medium G.I.

A smaller meal or healthy snack could be eaten 1 to 1½ hours before exercise and have a medium to high G.I.

Post exercise you are able to replenish your energy levels more quickly within the first 2 hours. This would be the best time to eat.

Protein

Protein is used by the body for growth and repair of muscle tissue that is broken down through exercise. Weight training will require us to eat a higher proportion of protein due to the larger demands on our muscles. However, once the body has used the protein required, the remaining amount will be stored as fat.

Protein is found in all meats, fish, and dairy produce and in smaller quantities in beans, lentils, nuts and seeds. Higher quality protein is found in lean meats, chicken/turkey, fish, pulses and Soya. Protein such as cheese, yogurt, eggs and nuts, all contain high levels of fat and should therefore be eaten in lower quantities. It is still important to eat dairy products though as these give us the calcium we need to keep our bones and teeth strong.

Proteins are composed of amino acids. These are categorised as Indispensable (primary/essential) and Dispensable (secondary). The body needs to obtain indispensable amino acids from foods such as fish, chicken, meat, and generally animal products. If all of these are present in a particular food, that product can be classed as being of ‘high biological value’. If all of the indispensable amino acids are not present then the protein source for that particular food is viewed as being of ‘low biological value’. We need to try and get all of the essential amino acids in the same meal so that our bodies can use the food as a protein source. Nine of the amino acids must be provided by our food and only some foods contain all these.

High biological value
Low biological value
Meat
Beans (most varieties)
Poultry
Nuts and seeds
Fish and shellfish
Lentils and peas

Milk, cheese, yogurt

Bread, potatoes, cereals
Eggs
Green leafy vegetables
Pasta and rice

Fat

Fat provides us with twice as much energy as both carbohydrate and protein and is needed for insulating and protecting the body (i.e. around the internal organs). It also allows us to absorb fat-soluble vitamins A, D, E and K.

Fat is the main fuel source when exercising at low-level intensities. (We must, however, exercise for a longer period)

Any foods eaten in excess regardless of what type, will be stored as fat. Fats can be placed into two categories:­

- Saturated (solid at room temperature)

- Unsaturated (liquid at room temperature)

Saturated fats are animal derived and are not essential in the diet. They are also linked to high rates of coronary heart disease due to increasing the levels of ‘bad’ cholesterol in the blood and the tendency for the blood to clot. Generally this source of fat is higher in calories and does not contain ‘Essential fatty acids’ required by the body.

Unsaturated fats are plant derived and 60% of our fat calories should come from this source. Another good source of fat is the monosaturated kind.

Common sources of each type of tat are below:-

Saturated
Polyunsaturated
Monosaturated
Beef
Olive Oil
Corn Oil
Butter
Peanuts
Mayonnaise
Cheese
Peanut butter
Soybeans
Chocolate
Peanut Oil
Sunflower Oil
Cream
Vegetable Oil
Lamb

 

How much should I eat?

Your intake of fat should be relative to your calorie consumption. As mentioned before your fat intake is recommended as 25-30% of your total calories. The table below will give an idea of the recommended amount of fat grams you need to consume for a particular calorie diet.

Total amount of calories

Recommended daily fat intake
1500
41-50g
2000
55-66g
2500
69-83g
3000
83-l00g

Remember, most of your fat intake should come from unsaturated fats found in olive, rapeseed and sunflower oil, nuts (all kinds), seeds (e.g. Sunflower, sesame, pumpkin), oily fish (e.g. sardines, mackerel, salmon), peanut butter and avocado.

These fats are also called Omega-3 Polyunsaturated Fat (essential fat found in fish and flaxseed) and Omega-6 polyunsaturated Fat (essential, though found in many foods including meat, eggs. dairy products and vegetable oils used in food processing). As the Omega-6 option is so easily obtainable we tend to eat too much of it and a lot of the foods containing this fat also contain saturated fats. The more beneficial option would therefore be the Omega-3 fat, or monosaturated fats.

Vitamins and minerals

Vitamins are nutrients that the body needs in small amounts for growth, health and physical well-being. They are involved in energy production and exercise performance, the functioning of the immune, hormonal and nervous system. Our bodies cannot make vitamins therefore they must be supplied by the diet.

Minerals are metals and salts required in small amounts. Some form part of the structure of bones and teeth such as calcium and phosphate. Others are involved in controlling the fluid balance in tissues, and help with muscle contraction, formation of red blood cells and nerve function. Minerals also need to be supplied by the diet.

It you are unsure as to whether or not you have good balanced diet it maybe worth taking a vitamin and mineral supplement. Food packaging often relates vitamin and mineral amounts to the food when it is fresh, raw and unprocessed. To prevent deficiency, select the correct foods as part of a varied and nutritional diet, and to safeguard your vitamin intake further, eat one or more of the list below on a daily basis.

l. Fruit

2. Bread and cereal

3. Vegetables, salad and potatoes

4. Milk, cheese and dairy products

5. Meat, fish and eggs

6. Fats, oils, butter and margarine

7. Drinks

Food should be eaten as near to it’s natural state as possible. Cook food for the shortest time and at the lowest temperature to avoid vitamin loss. Vitamins are destroyed due to, too much light or heat.

Stored vegetables and fruit can lose 40% of their vitamin C content after just one day!

Tips to prevent vitamin loss

Do not leave vegetables and fruit to stand in water.

Cut larger pieces and eat as soon after preparation as possible.

Do not peel potatoes or fruit, the vitamins are found under the skin.

Try to steam vegetables instead of boiling.

Freeze fresh products immediately if they will not be consumed, this will help preserve vitamins.

Food Labels

When selecting a particular product to buy it is a very good idea to read the label. Not all products are as beneficial or as low in fat as they first seem!

The legal requirements for information on food labels are as follows:

- Name of food

- Country of origin

- Name and address of maker

- Ingredients listed by weight. including additives (name or E number)

- Use by or best before dates

- Instruction for safe storage

- Nutrition labeling

Most products will also contain the following information:-

Energy …..Kcal
Fat …..g
Kj
(of which saturates) g
Protein g
Fibre g
Carbohydrates g
Sodium g
(of which sugars) g

 

On food labels the ingredients will always be listed greatest first. Most foods will inform you of the calorie content for the whole product, however some will only explain how many calories there are per 100 grams. Ensure you check how many grams the product contains so you are aware of the total number of calories for the whole item. Some packaging will give the energy rating as kilojoules (kj). One calorie is the equivalent of 4.2 kilojoules.

It is recommended that we consume no more than 5g of salt each day. Most products will inform you of the sodium content not the salt content. In order to get an accurate salt content for a particular product it is necessary to multiply the amount of sodium grams by 2.5. If the food you are eating contains 2 grams of sodium then that food contains the total amount of salt required for the whole day. It is very easy to consume a high quantity of salt as a lot of processed foods contain high sodium levels. Too much salt the diet is sometimes a contributing factor for high blood pressure, but it is important to consume some salt, as it is essential in maintaining a balance in the body fluids. Salt is lost through sweating and must be replaced.

The vast majority of food labels will give you the amount of fat grams the product provides, though more importantly, the saturated fat. When trying to lose weight it would initially help if you cut down on the amount of saturated fat that you consume alongside a regular exercise regime. If a product states that it contains ‘hydrogenated vegetable fat/oil’ or ‘partially hydrogenated’ (which you may find particularly in bakery products and chocolate) then this is informing you that it is a commercially synthesised trans fat. These fats are formed from one type of fat to another and give you little nutritional value.

All fats, gram for gram, contain 9 calories. If something states that it is 95% fat free it does not automatically make the product low in fat. Do not immediately buy a ‘Go ahead’ or ‘Good for you’ product just because you think it will be better for you. Always read the label. If a product has less than 30% fat then it can be considered low in fat. An example of how to calculate this is below:­-

Kit Kat (48g)

Total calories (kcal) = 243

Total fat grams = 12.7 of which saturates = 8.6 (high)

To calculate the total amount of calories from fat = 12.7*9 = 114.3

To calculate the percentage of fat the product contains – (114.3/243)

*100 =47%

A Kit Kat would therefore be considered high in fat. Chocolate does taste nice but unfortunately it is generally high in fat and calories and should be eaten sparingly.

Fibre and water

Fibre and water work alongside each other in maintaining good health, aiding digestion and helping pass waste products through the body. Fibre is found in:

- Vegetables

- Whole grain and seeds

- Brown rice

- Oats

Water causes fibre to swell, helping you feel fuller. If you consume a high fibre meal you should hopefully feel full enough to abstain from fattening foods until your next meal. Generally, wholemeal items will have a more significant fibre content. The following is a list of foods you could incorporate into your diet to try and improve your fibre intake:

Wholemeal bread, rice and pasta

Cereals containing bran, grains or oats

(I.e. porridge, weetabix, bran flakes, all bran)

Fruit and vegetables (vegetables contain more fibre than fruit)

Beans and lentils

Soluble fibre, which is important in the control of blood glucose and cholesterol can be found in oats, rye, peas, beans, lentils, fruit and vegetables.

Insoluble fibre found in whole-wheat bread, rice, pasta, whole grain breakfast cereals, fruits and vegetables, is used for the prevention of bowl disorders such as constipation.

How much?

It is recommended that we consume 18g of fibre per day.

We can lose up to 3 litres of water a day through sweating, our urine and when exhaling. When exercising the body loses even more water and therefore is at a risk of dehydration. This can cause headaches, lack of concentration, fatigue etc. Try to drink water on a regular basis and

especially when exercising (you can lose as much as half a litre of water in an hour!). Pure cold water would be more beneficial than juice, pop or tea as it is more easily absorbed into the blood stream. Caffeine actually counteracts our hydration levels, so consuming a lot of tea or coffee (or alcohol!) would require more water to be drunk. A guideline for adequate hydration is around 1.5 litres of water a day, or 10— 12 cups. All foods containing a lot of water including fruit and vegetables will help with hydration levels. (Remember, vitamins B and C are water-soluble!)

How do I know if I am hydrated enough?

You may sometimes wake up feeling like you have a ‘hangover’ or you have a bad headache, this is a sign of dehydration. Any sort of tiredness you feel may not only be due lack of sleep but to a reduced water intake and poor diet. Good indicators of hydration include clear bright eyes, stronger and less brittle nails and clear urine, (the darker your urine the more dehydrated you are).

Click on the following links for more inforamtion on dehydration; nhsdirect, wikipedia and symptomsOfDehydration.

Losing weight

Effective weight loss is never quick and generally not that easy. If we are trying to lose weight we need to consume less calories than our body requires. During exercise we ‘burn’ calories, this helps us with an increased weight loss. One pound (1lb) of fat is equivalent to 3500 calories. We will need to burn this through exercise or alternatively, reduce our calorie intake by this amount to lose 1 lb in weight. This also works the other way around. Eat 3500 calories (easily done!) more than you need and your weight will increase by 1lb. Safe and effective weight loss is done gradually. Aim to lose 1 to 2lbs a week. You may find that initially you lose more than this but most of it will be water, especially if you have cut down the amount of carbohydrate you eat.

Try not to totally eliminate a particular food constituent from your diet as this may reduce the nutrients your body needs. It would be more appropriate to reduce the total amount of calories you eat.

If placed on a similar calorie diet, each individual will lose weight at slightly different rates depending on their metabolism. This is very difficult to determine, however, exercise will help you increase your metabolism and weight training will be of great benefit as the greater your muscle mass, the more calories you will require to sustain your weight. This is generally the reason men find it less difficult to lose weight. Genetics can also play their part in determining the rate of your metabolism.

After dieting for some time, the basal metabolic rate (i.e. the number of calories required by the body at rest) will drop. This is an automatic response to the reduction in ‘fuel’ and the body presumes it is being placed under famine conditions. In order to protect itself from starvation, the body will then try to hold onto its fat reserves. Try not to reduce your calorie intake by a drastic amount and ensure you exercise on a regular basis to counteract this happening.