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Eating for Health
Carbohydrates in a healthy balanced diet | How much carbohydrate should I eat? | Sugar and diet quality | Carbohydrates' role in appetite | Sugar and health | Which foods are high in carbohydrate? | Breakfast - the most important meal of the day! | The role of fat in a healthy, balanced diet | Protein in the diet | Supplementation | Being active
Eating a healthy, balanced diet along with taking regular exercise is key to physical and mental wellbeing. No foods should be considered as ‘good or bad’ as all foods play an important role in the diet. It is only when foods are eaten in excess that health problems result.
What you eat has an important impact on how you cope with daily activities. By choosing a carbohydrate-rich diet you will notice that you are able to keep going for longer and are less tired afterwards. Current scientific evidence shows that individuals who consume a low-fat, high-carbohydrate diet, rich in fruit and vegetables, tend to be lean rather than overweight or obese.
If you would like to lose some weight, don’t try starting a low energy diet and exercise programme together. It will leave you feeling tired, irritable and inclined to give up the whole idea. Instead, try boosting your carbohydrate and reducing your fat intake. You can then adjust the amounts you eat once you are in the habit of exercising. For information on how to lose weight and keep it off, see Successful Dieting.
Carbohydrates in a healthy balanced diet
A healthy balanced diet is essential for good health. The key to making our diet healthy and balanced is simply a variety of foods and everything in moderation. Moderation is important, because anything over-consumed will unbalance the diet and in the case of some nutrients - fat and alcohol in particular - could also lead to health problems. As for variety, this will not only make the diet more interesting and enjoyable, but will also help ensure that the requirements for all the micronutrients - vitamins and minerals - are met.
The balance part takes it a stage further and divides the key nutrients up into proportions. For health, over half (55%) of our energy intake should come from carbohydrates, and for regular exercisers this should increase to more like 60-70% of energy from carbohydrates. The rest of the diet should be made up by a bit of protein (around 12-15%) - about half of what most of us eat - and some fat (less than 30%).
A healthy diet is only half the story. At least as important to health is regular exercise. And choosing the right diet can help make exercise more enjoyable. Carbohydrates are particularly important in the diet of anyone who exercises regularly.
Carbohydrates
Carbohydrates are all the starches and sugars in the diet and they can be divided into three basic groups:
Monosaccharides
These are single molecules of sugar. The monosaccharides are:
- Glucose
- Fructose
- Galactose
Glucose is found in many fruits and is a component of most carbohydrate foods including sugars and starches. Most carbohydrates are eventually digested or converted into glucose by the body for energy (fuel). Fructose is also known as fruit sugar as it is found, along with other sugars, in fruits, vegetables and honey. It is mostly converted into glucose by the liver. Galactose is part of lactose, the sugar found in milk.
Disaccharides
These are two linked sugar molecules which are broken down into the monosaccharides by digestion. The disaccharides are:
- Sucrose which is made up of glucose + fructose
- Lactose = glucose + galactose
- Maltose = glucose + glucose
Sucrose (table sugar) normally comes from sugar beet and cane, which happen to be rich sources of this natural sugar. But sucrose can also be found naturally in all fruits and vegetables, and even most herbs and spices. Lactose is found in milk and milk products. Maltose is formed when starch is broken down.
Starches
Starch is simply hundreds of molecules of glucose sugar joined together. When starch is digested, it is first broken down into maltose and then into glucose. So, the only difference between sugars and starch is the size of the molecule. Ultimately, most carbohydrates will end up as glucose to provide that vital energy fuel.
How much carbohydrate should I eat?
Carbohydrates help to switch off hunger when you have had enough. So boosting the level of carbohydrate-rich foods in the diet not only fuels your muscles, but helps to prevent overeating.
When eating a meal, the pasta, potatoes or rice should take up a much larger part of the plate than the meat, sauce or other main course. Don’t forget to add plenty of vegetables. Finish off with a fruity, low-fat dessert.
If you have sandwiches, use thick slices of bread, less meat or cheese and plenty of salad or pickle.
There is no need to cut out fat or fatty foods altogether. Many are important sources of nutrients in the diet, for example, meat is rich in iron, and dairy products are rich in calcium. Just make sure you tip the balance in favour of carbohydrates.
After exercising or completing strenuous activities your muscles will need refuelling. A good way to do this is to have a high-carbohydrate meal, snack or drink.
Carbohydrate requirements
Just how much carbohydrate we need depends on the amount of activity we do - the more sport and exercise we do the more carbohydrates we need to consume. There are two ways of working out our carbohydrate needs. Most recommendations state them in terms of percentages - ie 55-70% food energy (daily calories) from carbohydrates, depending on our physical activity levels. However, it is difficult enough to guesstimate the proportion of carbohydrate-containing foods in one meal, let alone drinks and food for the rest of the day.
The other, and probably simpler, way to calculate our daily carbohydrate needs is to first work out how much we require, depending on the number of hours of exercise we do, and then multiply that by our weight in kilograms. For example, if someone weighs 60kg and exercises for about an hour each day, their daily carbohydrate requirement would be: 60 x 6 = 360g of carbohydrates.
The bulk of our carbohydrate intake should come from the starchy sources such as bread, rice, potatoes and pasta and the remaining from more sugary sources such as sugar, fruit and juices. All the expert committees that have reviewed the evidence in the last ten years have come to the same conclusion: that sugar has a useful part to play in healthy balanced diet. Furthermore, as most carbohydrate foods, for example pasta or sugars, are eventually broken down into glucose, one type is not intrinsically better than the other, so we can rely on our taste preference to limit sugar consumption.
Sugar and diet quality
Sugars are often cited as a source of ‘empty calories’ that displace nutrient-dense foods, resulting in a dilution of diet quality. However, the scientific evidence available to date concludes that sugar can be included as part of a normal, healthy balanced diet and, providing that energy needs are met, it is unlikely to adversely affect the nutrient quality of the diet or the variety of foods consumed. What's more, the body cannot distinguish between added sugars and naturally occurring sugars, such as those in grains, fruit and vegetables, so focusing purely on added sugars, rather than the diet as a whole, is not particularly useful.
The optimal diet for weight control is a low-fat, high-carbohydrate diet, that limits total energy (calories) to what is needed. Of the specific nutrients, the major health focus is on limiting saturated fat intakes. Research has shown us that dietary fat intakes can be reduced overall simply by increasing the amount of starchy and sugary carbohydrates in the diet. In addition, the sugar plays a useful role in helping make a low-fat diet more palatable and therefore easier to stick to.
Carbohydrates' role in appetite
It is also well known that all carbohydrates are satiating, making us feel full, and therefore their consumption helps regulate appetite and food intake. The sweet taste of sugars has also been shown to play a specific role in suppressing appetite.
Sugar and health
The expert committees have also noted that the balance of available evidence does not implicate sugar in any of the ‘lifestyle diseases’ obesity, diabetes, coronary heart disease, or cancer at any site. These health issues in relation to sugars and carbohydrates are covered in more detail in the Science Centre.
When it comes to exercise, research has shown that diets high in carbohydrate, whether obtained from sugars or starches, are equally effective in improving performance. However, regular exercisers need to eat a lot of carbohydrates, and quite frankly there is only so much bread and pasta one can eat, so this is where sugary snacks and drinks have a useful role to play, both in providing energy before exercise, and in helping restock glucose stores after exercise, ready for the next training session.
Which foods are high in carbohydrate?
Carbohydrates come in the form of starch and sugars, and are found in many foods. Some good examples of carbohydrate sources are:
- All types of bread, pasta, noodles, rice and potatoes
- Breakfast cereals
- Peas, beans, lentils and chickpeas
- Fresh, dried or canned fruit
- Jam, honey and marmalade
- Fruit juices and regular soft drinks
- Puddings, cakes, biscuits, cereal bars and confectionery all contain carbohydrate - but choose those with a lower fat content. Some lower fat examples include: arctic roll, sorbets, fruit yoghurt, trifle, rice pudding, currant buns, jaffa cakes, fig rolls, jelly beans, jelly babies and mints.
As well as being good sources of carbohydrate and containing virtually no fat, fruit and vegetables also provide important vitamins and minerals. Try to include at least five portions in your meals and snacks every day.
Examples of 1 portion include;
- A glass of orange or other fruit juice
- 2 tbsp vegetables - raw, cooked, frozen, canned
- 1 dessert bowl of salad
- 1 apple, banana or orange
- 2 plums
Supermarkets now stock a wide range of fruit and vegetables. Experiment with those you have not previously tried to add variety to regular meals.
Breakfast - the most important meal of the day!
Eating a healthy breakfast helps to get the day off to a good start. After an overnight fast your body's energy stores need replenishing to give you the energy to get on with your work. Skipping breakfast usually leads to a lack of concentration and continuous snacking throughout the day, often on high-fat foods. A high-carbohydrate breakfast is ideal for providing the energy you need.
Try eating breakfast cereal, served with skimmed or semi-skimmed milk, with some fresh fruit or fruit juice. If you prefer toast, use thickly-cut slices of white or brown bread, or a bagel, and use low-fat spread sparingly with either jam, marmalade or honey. If you do want to have a cooked breakfast every once in a while, try grilled bacon with poached eggs and plenty of toast, rather than the traditional 'fry-up'.
The role of fat in a healthy, balanced diet
In the past low-fat, low-sugar diets were advised as part of a healthy, balanced diet. Research has shown, however, that people who consume a high-sugar diet tend to consume lower amounts of fat and vice-versa. Sugar provides less than half the calories provided by fat (4 calories per gram of sugar compared to 9 calories per gram of fat). So including sugar, and other carbohydrates, in the diet will help to reduce the total energy consumed.
Consuming a diet low in fat does not mean having to eat a fat-free diet. It is essential to have some fat in the diet. Fat is required for energy production and to supply essential fatty acids and fat-soluble vitamins (A, D, E, K). Avoiding all foods that contain fat reduces the variety of foods eaten and can lead to nutritional deficiencies.
Fats can be divided into three types, depending on the fatty acids they contain:
- Saturated Fatty Acids (SFAs)
- Monounsaturated Fatty Acids (MUFAs)
- Polyunsaturated Fatty Acids (PUFAs)
PUFAs contain the Essential Fatty Acids (EFAs) n-6 (omega-6) and n-3 (omega-3). These are termed essential because they cannot be made in the human body and must be supplied by the diet. N-6 PUFAs are common in most diets and are present in nuts, seeds, vegetable oils and margarines. N-3 PUFAs are less common in the UK diet, as these are found in oily fish (such as mackerel, salmon, tuna, herring), linseeds, pumpkin seeds and walnuts. Current dietary recommendations suggest consuming 2-3 portions of oily fish per week to obtain the necessary level of n-3 PUFAs.
The type of fatty acids consumed is very influential to health. Diets containing more unsaturated fatty acids (MUFAs and PUFAs) and less saturates (SFAs) have been shown to decrease total cholesterol levels, especially LDL cholesterol. High levels of LDL cholesterol are associated with Coronary Heart Disease (CHD) development. Very low fat diets, however, also reduce the levels of the protective HDL cholesterol in the blood. Incorporating foods that supply unsaturated fats, for example, avocado, nuts, seeds, oily fish and olive oil, into the diet will increase variety and improve the flavour of meals.
Protein in the diet
Protein is a macronutrient essential for - growth and repair of tissues; transport of oxygen and nutrients in blood and cells; a healthy immune system; and regulation of fluid levels within the human body. Requirements are especially high in young people, pregnant and nursing women and following traumatic experiences or physical injury.
Meat, dairy products, fish, eggs, cereals, nuts and pulses (peas, beans and lentils) are all important sources of protein. The preconception that these foods are high in fat often leads to them being wrongly excluded from the diet. Choosing low-fat varieties of such foods, for example, semi-skimmed milk and leaner cuts of meat, can help to keep the total fat content of the diet low.
High-protein, low-carbohydrate diets tend to be high in fat and are not nutritionally adequate. Consuming a high-fat diet over a period of time has been shown to increase the risk of obesity, Coronary Heart Disease (CHD) and stroke.
Supplementation
Eating a wide variety of foods as part of a healthy, balanced diet will provide all the nutrients essential for health. In general there is no need to take dietary supplements. Deficiency can normally be corrected by adding foods to the diet that are rich in the lacking nutrients. In certain circumstances, however, supplementation may be required, for example, iron deficiency in vegetarians or vitamin B12 in strict vegetarians (vegans).
It is not advisable to take individual vitamin or mineral supplements, unless advised to by your GP. Nutrients levels are regulated by the body creating a natural balance. Taking high levels of one or two individual nutrients could upset this balance and cause more harm than good.
If you do decide to take a supplement for general health, choose an all-purpose multi-vitamin. In doing so, the balance of nutrients within the body will be maintained and it is unlikely that toxic quantities will be consumed.
Being active
Many benefits can be gained from being active. Everyone should try to live an active lifestyle, not just, as is commonly thought, those who are trying to lose weight. Increasing activity levels will help to increase your energy levels, motivation and concentration levels.
All types of physical activity are beneficial to health. The important thing is to enjoy yourself whilst getting the heart rate going regularly. Your heart doesn’t know if your muscles are dancing, jogging or spring-cleaning the house!
Everyone is different, both in terms of their level of fitness and their preferred activities. Choose activities that you will enjoy and can manage comfortably. Being active should be a fulfilling part of life, not a chore! Taking a friend along may make it more enjoyable and provide an incentive to attend regularly. Group activities can also help to make new friends.
How do I get started?
Getting started is easy. Take a look at your daily routine. Try to think how you can make changes that will increase your activity level. These changes may only be minor but every little helps.
Simple changes may include the following suggestions:
- Go for a short walk
- Use the stairs instead of the lift
- Cycle or walk on shorter journeys instead of driving or taking the bus
- Get off the bus or underground a stop early and walk the extra part
- Take young children or pets for regular walks in the local park
- Take up a new hobby to get you out and about instead of watching television
- Many communities have organised group-activities, such as walking groups, exercise classes or sports lessons, for varying levels of fitness and abilities, that take place regularly. Contact your local community or leisure centre and see what is happening in your area.
Realistic targets
Set realistic targets when increasing activity levels. Don't try to run before you can walk! Gradually, as your fitness level improves, you can build up the amount and level of activities you take part in, if you wish. This will increase your chance of success. Being over-ambitious to begin with may leave you feeling discouraged and likely to give up. Keep going until the new routine becomes part of your daily lifestyle. Regular activity helps to delay one of the most important aspects of ageing - the decline in the ability to get around.
A healthy appetite
Being active actually helps to regulate your appetite so you eat just what you need. In the long term this helps to maintain a stable weight and prevent weight gain. Eating enough carbohydrates, in the form of starch and sugar, is a vital part of an active lifestyle. The more physically active you are, the more calories you need. If you are already slim this means you can enjoy your food even more without gaining weight.
Fluid requirements
An active person needs plenty to drink to prevent dehydration and tiredness. It is important to replace the fluid you lose during activities. As a guide you need to drink about a pint of water or other non-alcoholic drink for every 30 minutes of activity, and more in hot environments. Have a drink while you are being active or as soon as you can afterwards.
Water is a good choice to drink during everyday activities. If you are working hard, however, ordinary squash, sports drinks or other soft drinks can be useful, as they help replace vital carbohydrates as well as fluid.
If you drink alcohol after exercising, make sure you have some water or soft drink first.
Key References
- See also Fitness Zone, which includes further information on carbohydrates and protein.
- Anderson G.H., Catherine N.L.A., Woodend D.M. and Wolever T.M.S. 2002. Inverse association between the effect of carbohydrates on blood glucose and subsequent short-term food intake in young men. American Journal of Clinical Nutrition, 76, pp1023-1030.
- Bowman S.A. and Spence J.T. 2002. A comparison of low-carbohydrate vs. high-carbohydrate diets: energy restriction, nutrient quality and correlation to body mass index. Journal of the American College of Nutrition, 21(3), pp268-274.
- Department of Health. 1989. Dietary Sugars and Human Disease. Committee on Medical Aspects of Food Policy. Report on Health and Social Subjects No 37. HMSO, London.
- Department of Health. 1992. Dietary Reference Values for Food Energy and Nutrients for the United Kingdom. Committee on Medical Aspects of Food Policy. Report on Health and Social Subjects No 41. HMSO, London.
- Deutsche Gessellschaft fur Ernahrung, mit Osterreichische Gesellschaft fur Ernahrung, Schwiezerische Gessellschaft fur Ernahrungsforschung und Schweizerische Verienigung fur Ernahrung. 2000. Referenzwerte fur die Nahrstoffzufuhr. Umschau/Braus, Frankfurt am Main.
- Food and Agriculture Organisation of the United Nations & World Health Organisation. 1998. Carbohydrates in Human Nutrition. Report of a Joint FAO/WHO Expert Consultation. FAO Food & Nutrition Paper 66.
- Forshee R.A. and Storey M.L. 2001. The role of added sugars in the diet quality of children and adolescents. Journal of American College of Nutrition, 20(1), pp32-43.
- Gibney M.J., Sigman-Grant M., Stanton J.L. and Keast D. 1995. Consumption of sugars. American Journal of Clinical Nutrition, 62(suppl.), pp178S-194S.
- Gibney M.J. and James W.P.T. 2001. Nutrition and diet for a healthy lifestyle in Europe: the Eurodiet Project - Carbohydrates. Public Health Nutrition, 4(2A), pp402-405.
- Gibson S.A. 1997. Micronutrient intakes of British pre-school children: association with non-milk extrinsic sugars (NMES). British Journal of Nutrition, 78, pp367-378.
- Gibson S.A. 2002. Dietary sugars and micronutrient dilution in normal adults aged 65 years and over. Public Health Nutrition, 4(6), pp1235-1244.
- Health Council of the Netherlands. 2001. Dietary Reference Intakes: energy, protein, fats and carbohydrates. Health Council of the Netherlands, The Hague.
- Institute of Medicine of the National Academies. 2002. Dietary Reference Intakes for Energy, Carbohydrate, Fiber, Fat, Fatty Acids, Cholesterol, Protein, and Amino Acids (Macronutrients): A Report of the Panel on Macronutrients, Subcommittees on Upper Reference Levels of Nutrients and Interpretation and Uses of Dietary Reference Intakes, and the Standing Committee on the Scientific Evaluation of Dietary Reference Intakes. The National Academies Press, Washington.
- Kafatos and Codrington Eds. 2001. Eurodiet - Reports and Proceedings. Public Health Nutrition, 4:2(a) Special Issue.
- Lavin J.H., French S.J., Ruxton C.H.S. and Read N.W. 2002. An investigation of the role of oro-sensory stimulation in sugar satiety. International Journal of Obesity, 26, pp384-388.
- Warren JM, Henry CJ, Simonite V. 2003. Low glycemic index breakfasts and reduced food intake in preadolescent children. Pediatrics, 112(5):e41.
- World Health Organization / Food and Agriculture Organization. 1996. Preparation and use of food-based dietary guidelines. Technical report series 880. WHO, Geneva.
