Changes in dietary energy with novel proteins and fats

Obesity and heart disease are two of the major health concerns in the Western world.As a consequence of these and other nutritional concerns, it has been suggested that the amount of energy derived from fat in the diet should be reduced.Many of the nutritional factors involved are not fully understood but the perceived health issues have led to increasing pressure into ways of reducing the fat content of foods.A number of products that are intended to aid a reduction in fat intake are already available; for example, low-fat spreads and milks, oven chips and aerosol creams.It must be remembered, however, that without fat, meals often lack flavour and other pleasant organoleptic properties that are associated with fatty foods.Additionally, it is clear that there are nutritional needs for oils and fats and, although a reduction in the amount of fat consumed might be beneficial, a balanced diet containing fat is essential.Nonetheless, for some time investigations have been undertaken in an attempt to find the ideal fat substitute.Studies on the digestibility of rapeseed oil were carried out by Deuel(l948), and several workers, including Channon & Collinson (1929), have studied the absorption of mineral oils.In the mid to late 1980s, a number of potential replacements of fat were proposed and some have gained 'generally regarded as safe' (GRAS) status, and are incorporated into foods sold in the UK.There are, however, certain obstacles that threaten the development of fat substitutes.For example, more information regarding the potential metabolism of unabsorbed fat in the gut might be required.In addition, concern has been expressed over the potential of certain fat substitutes to reduce the absorption of fat-soluble vitamins.Unlike many other food additives or ingredients, the probably high intakes of fat substitutes will mean that certain fat mimetics will require most considerable safety testing.Nutritionists are also concerned that the use of fat substitutes will encourage poor eating habits since large quantities of ice-cream and snacks, for example, might be consumed at the expense of fruit and vegetables.It should be remembered, however, that fat substitutes provide less energy than conventional fats and, thus, they provide a means for reducing dietary fat to levels recommended by the National Advisory Committee on Nutrition Education (1983) and Committee on Medical Aspects of Food Policy, Department of Health and Social Security (1984) reports.In addition, certain fat substitutes are associated with a lowering of blood cholesterol levels.It is the purpose of the present paper to review the three main groups of fat mimetics and to examine their properties and uses.It may be considered that fat mimetics fall into two main groups: those based on gels formed from modified starch or proteins and those based on fatty acids or fatty alcohols that are esterified to a number of components in such a way that metabolism of these compounds does not take place. THE MALTODEXTRINSThis group of compounds is based on starch and, when incorporated into food products, might be considered to be high in water and low in solids.A number of products of this