plants. Energy for a balanced human diet is supplied by carbohydrates, fats and proteins.
             A balanced diet can (and should) come from a variety of different foods, calculated to give the desired levels of carbohydrates, proteins, fats, vitamins and minerals.
             Nutritional scientists advocate that carbohydrates should provide at least 50% of our energy requirements - i.e. energy not alone for physical activity but also for all other continuous processes such as breathing, thinking, eating and sleeping.
             All carbohydrates are acted upon by the body to provide the necessary glucose supply for energy. The brain in particular must have a constant supply of glucose. If this is not readily available from ingested carbohydrate stores, then the body will have to increasingly turn to a process known as glucogenesis. This describes the production of glucose from non-carbohydrate sources such as fats and proteins.
             Starches provide the larger part of our carbohydrate needs. The sugars which nature provides alongside the starches in our food supply have also a very special role to play in human metabolism. For primitive man the sweet taste probably acted as a signal that the food was safe to eat. For modern man sugar is used to improve the palatability of many foods and can thereby encourage a more varied diet. For example, a grapefruit is an excellent source of Vitamin C which most people find too bitter to take without sugar. Likewise, many breakfast cereals may be lacking in taste and may actually contain too much fibre unless some sugar is added to them.
             All green plants make sugars. Through water and minerals in the soil and absorbing carbon dioxide (CO2) from the air they produce chlorophyll.
             Chlorophyll uses light energy from the sun to combine CO2 and water (H2O) to produce sugar. Plants also release Oxygen (O2) into the air as a by-product.
             The process by which plants make sugar is photosynthesis from the Greek 'photo' (light) and...