Fat Substitutes in Low-Calorie Diet
Fat substitutes are food additives used to replace fat in low calorie foods that give foods the same characteristics (appearance, taste, stability, texture, etc.) they would have if prepared with fat. They not only contain fewer calories than fat but they are also lower in saturated fat and cholesterol.
Dietary fat is not only a source of energy, it also provides flavour, volume and texture to foods. Fat substitutes are designed to mimic the positive attributes of fat while minimizing the health risks associated with certain types of fat. They are made from carbohydrates, protein, fat or their combination. Usually, a combination of these components is necessary to mimic the texture and taste of a single fat.
Fat substitutes are added to low-fat or fat-free versions of foods that normally contain fats. Such products may include baked foods, cookies, candy, cheese, ice cream, margarine, mayonnaise, table spreads, sour cream and salad dressing.
Although fat substitutes allow people to reduce their intake of calories, saturated fats and cholesterol, consumers should not view them as a way to avoid eating a healthy, nutritionally balanced diet.
Types of Fat Substitutes
Some fat substitutes act as “fat replacers” whereas others mimic the properties of fat, such as texture and taste. They generally include:
Carbohydrate-based substitutes. They are made from plant polysaccharides that absorb water and take on a thickness and creaminess which is similar to natural fat. Such ingredients include:
- Polydextrose – serves as a bulking agent to replace volume lost due to removal of fat.
- Modified starches, dextrins and malodextrins – absorb water and form gels that mimic the texture of fat.
- Cellulose gel – cellulose ground to microparticles lends a mouth feel similar to that of fat.
- Gums – help stabilize emulsions and provide a creamy mouth feel.
- Soluble fiber – includes several variations used as bodying and texturizing ingredients.
Calories in these substitutes range from almost zero to four calories per gram as compared with nine calories per gram in fat. Substitutes such as modified starches or dextrins are digested and provide the body with some energy. However, fiber-based substitutes such as cellulose cannot be digested and, therefore, provide no energy to the body. Carbohydrate-based products cannot be used to replace fats in frying, but are often useful in baking.
Protein-based fat substitutes. These substitutes are made with protein from egg whites, fat-free milk or whey protein. They stabilize emulsions, improve appearance and texture and provide a creamy sensation to foods. Protein-based fat substitutes are not used in foods prepared at high temperatures (e.g., fried foods) and are not useful in baking. They provide between one and four calories per gram, depending on whether or not they are mixed with ingredients that cannot be digested.
Fat-based substitutes. They are mostly made with chemically altered fats that are only partially digested and absorbed by the body. Examples include emulsifiers, Salatrim, Sorbestrin and Olestra/Olean (rarely used these days due to its potential for causing digestive discomfort). Sorbestrin provides 1.5 calories per gram, Salatrim 5 calories per gram and emulsifiers 9 calories per gram, which is the same amount as fat but less is used by the body. Unlike carbohydrate- and protein-based fat replacers, many fat-based substitutes can be used for frying and baking. In addition, plant stanol esters and plant sterol esters are used as substitutes in fat containing foods (e.g., spreads, salad dressings) to help lower “bad” cholesterol levels. Certain stanol ester products can be used in cooking, but sterol ester products are only available as table spreads.
Health Effects of Fat Substitutes
Fat substitutes are primarily used as a way to lower overall fat intake in order to help people lose weight and improve their general health. However, these food products should not be consumed excessively. Foods made with fat substitutes still contain calories and fat and should be eaten in moderation. They can cause temporary digestive discomfort in some people, or when consumed in large quantities. In addition, some fat-based substitutes may also affect the body’s ability to absorb the fat-soluble vitamins A, D, E and K. Therefore, these vitamins are often added to products made with such substitutes.
Although all FDA-approved fat substitutes are considered safe, their long-term health benefits and record of safety remain unknown. The potential effect of fat substitutes on the digestive tract is not fully understood and their long-term cumulative effect on health is not known. For this reason, patients with digestive or nutritional disorders should contact the doctor before incorporating fat substitutes in their diet.
Where to Find More Information: Calorie Control Council