Public awareness of the health risks caused by dietary fat has increased dramatically. Today's Americans are fat-phobic. However, people find it difficult to reduce their fat intake primarily because fat greatly enhances the flavor of foods. Consequently, the food industry for the past decade has worked hard to produce non-fat mimics of fat.
Fat substitutes are made from carbohydrate, protein, fat, or a combination of these components. Carbohydrate-based fat substitutes include gums, aligns from kelp, modified food starches or oat and wheat fiber. The carbohydrate-based fat substitutes absorb water and imitate the thickness and creaminess of fat and are useful in some baked products, processed meat products, spreads, dips, frostings, soups, and frozen desserts. These fat replacers do not work for frying (1).
The protein-based fat substitutes are made by heating and blending (microparticulation) milk and egg-white protein or they are produced from a mixture of egg-whites, whey protein, and xanthine gum. Their usefulness is very similar to the carbohydrate products mentioned above. They are not well suited for baking and cannot be used in frying (1).
The fat-based substitutes that have recently attracted public attention include the sucrose polyester which is known as olestra (now also known as Olean). Olestra is made by binding (esterifying) 6-8 fatty acids to a sugar (sucrose) molecule. Olestra has all the characteristics of real fat in reference to taste and texture contribution and performs like regular fat in baking and frying procedures. However, the digestive enzymes of the small intestine are not able to digest Olestra. Consequently, Olestra passes through the digestive system without the fatty acids being absorbed. Thus, it contributes near zero calories. Recently the Food and Drug Administration did approve Olestra for limited usage in snack foods.
The general negative concerns that the nutritionists have for this product relate to a fat that passes through the digestive system without being absorbed. An unabsorbed fatty material may bind fat soluble vitamins and result in a loss of these important nutrients. Additionally, an unabsorbed fatty material has a potential of producing real disturbances in the large bowel. These concerns have also been expressed by Dr. David Kessler of the Food and Drug Administration. Since the effect of a long-term use of Olestra (or Olean) containing products are unknown,
those products should be used sparingly.
Miller and Groziak (1) have reviewed the impact of fat substitutes on fat intake. They conclude that for short term, fat substitutes can decrease both dietary fat intake and percentage of caloric intake form fat. However, individuals have a tendency to compensate for this calorie reduction by increasing their consumption of other macronutrients. Specific studies using lean young men (2) and children (3) on diets utilizing Olestra as a fat substitute have shown that these subjects make a 75 - 80 percent compensation for the non-caloric fat by the consumption of calories form other nutrients.
Thus, it appears that we tend to fool ourselves with a low or no-caloric fat substitute. Rather, it is desirable that we establish a healthy lifestyle that is low in fat and high in fruits, grains, and vegetables and we do not play games with ourselves by trying to simulate a high-fat diet.