We need to eat a healthy diet and our requirements for specific nutrients will vary at different times in our lives - for example, in childhood, adolescence, pregnancy, menopause and old age.
Eating too little or defective digestion or absorption of nutrients can cause deficiency diseases. Therefore it is important to get the balance right, and we must ensure that we get sufficient but not excessive nutrients from the food we eat.
The link between being overweight or obese and lifestyle diseases is well established, and your primary goal should be to achieve and maintain a healthy weight. Body weight is all about energy balance, or kilojoules in versus kilojoules out. If you're overwight, a combination of reducing kilojoules from the food you eat plus burning more kilojoules through physical activity is the key to success.
Most nutritionists would agree that a healthy diet would include adequate amounts of protein, carbohydrates, fat, vitamins, minerals and fibre. It is now widely accepted that it is prudent to reduce our fat intake - both visible and invisible. For instance, invisible fat is present in a wide range of foods, including cookies, cakes, ice cream, pastries and some processed convenience foods.
We should also ensure that we include some unrefined whole-grain cereals in our diet, as these are a valuable source of fibre which helps prevent constipation and may protect against common bowel problems.
It is also argued that a reduction in salt can be beneficial, and while it is acceptable to season our food with salt, we should take care not to eat too many processed and canned foods which often contain large amounts of it. Most people consume at least 50 per cent more food than their bodies need, and high salt intakes have been linked in some cases with high blood pressure. However, it should be remembered that a certain amount of sodium is essential for our health and wellbeing.
We all need to eat several servings of fresh fruit and vegetables daily (see the diet table). They are good sources of vitamins and minerals and play an important role in health maintenance and disease prevention.
Diets should be base on the above table!
Many people are adopting a vegetarian diet and cutting out meat and fish and, in the case of vegans, dairy products too. If care is taken to design a nutritionally balanced diet with adequate protein, it is possible to obtain a fully satisfactory diet and maintain good health. Lacto-vegetarians who consume dairy products and eggs have no nutritional problems. However, vegans who restrict their food intake to vegetable foods only must ensure that they eat a wide range of foods including whole-grain cereals, beans and legumes, nuts, fruit, leafy vegetables etc. Iron deficiency can be a problem as the iron in vegetable foods is not absorbed as well as the iron in meat, so there is a higher risk of becoming anaemic. Vitamin B-12, which is found mainly in animal foods, may also be deficient, so vegetarians should take care that they obtain these essential nutrients.
People often talk about eating a "balanced diet", but what does this actually mean? Usually we choose to eat the food we like rather than the food that is nutritionally best for our health. Our diet is made up of a mixture of different foods, and this is how we obtain a supply of all the nutrients our bodies need. There is no precise prescription for the sort of food and the amounts we must eat in order to stay healthy, and individuals have differing requirements. We need to "balance" our food intake to meet our requirements for different nutrients. This means eating a range of foods from all the major food groups every day.
Most nutritionists also encourage the physical fitness aspects of health and will weave a lifestyle change into their recommendations. Walking on a regular basis (five times a week) is the most frequent suggestion, but for some the fellowship of group activity, such as dancing, playing tennis, bicycling or aerobic classes, is more acceptable. The more we learn about the effects of exercise, the less it seems we can truly say that one type of exercise is the best when one is only trying to increase motion and cardiovascular activity and not trying to create a marathon runner. In fact, jogging has many casualties among the older set because of the tremendous strain it places upon ligaments, tendons and cartilages which have been comparatively quiescent for many years.
This is a well rounded balance of needed nutrients and can be easily varied to be more in line with individual tastes. Fortunately most nutritionists do not encourage or force radical dietary changes but instead concentrate on the eliminiation of refind sugar and flour from foods, and those containing partially or completely hydrogenated oils or margarine, and any foods that are so refined and contain so many additives that it's questionable whether they should be called foods. It's amazing how even small changes in the type of food consumed can increase your feeling of wellbeing.
Reducing high fat consumption is another admonition which the nutritionist will give. Since fat increases the satiety value of foods, a high fat diet will often reduce the amounts of cereal grains, vegetables and fruits you consume. Instead of being the mainstay of the diet, these three are relegated to minor intake resulting in a diet which must lead to health problems. Fat should constitute approximately 30 to 25 percent of the diet with more being allowed in the cold climates and less in the temperature or tropical climates.