Fat: Friend or Foe
Science is coming to the defense of this "villain" of the food world.
For many years, accusing fingers were pointed at fats. Eating too much of fats is harmful. Fats increase the risk of obesity. Fats will lead to heart disease, cancer, and other diseases. On the other hand, some fats are essential for normal body function and good health. So, what is the true role of fats in the diet? Research by the Asian Food Information Centre (AFIC) attempts to clear up the murky picture.
Benefits from fat
Nutrition recommendations in the 1980s and onward practically demanded adopting low-fat diets. High-fat diets were said to contribute to obesity, heart disease, and cancer. But many scientists now question simple instructions to reduce fat intake, especially since emerging research is showing that the type of fat may be as important as the amount of fat you consume. They are saying that fat is necessary in the diet.
Fat is an energy source. Gram for gram, fat provides more than twice as many calories as carbohydrates and proteins. Fat provides 9 calories per gram; proteins or carbohydrates,
including sugars, reach up to 4 calories per gram. Fat supplies essential fatty acids such as linoleic and linolenic acids, which help regulate cholesterol metabolism, prostaglandin production, and the supply or absorption of fat-soluble vitamins A, D, E, and carotenoids. Most of the fat in the body is stored in adipose tissue (cellular fat), which insulates the body and cushions the organs.
Fats and health
One of the biggest changes in recent years is the report from the World Cancer Research Fund (WCRF) and the American Institute for Cancer Research on "Food, Nutrition, Physical Activity and the Prevention of Cancer," which was released in 2007. Unlike previous reports, this one specifically did not include a recommendation to reduce fat intake.
Here is what some research results are showing about the role of fat as a contributor to obesity, heart disease, and cancer.
- Cancer. Reviewing past research on the connection between dietary fats or oils and cancer risk, the WCRF 2007 report concluded: "... there is only limited evidence suggesting that diets relatively high in fats and oils [in total or any type] are in themselves a cause of cancer. This judgment contrasts with those of earlier reports which concluded from evidence then available that diets high in fats and oils might be a substantial cause of some cancers."
- Overweight and obesity. Body weight is determined by a complex interaction between genetic, metabolic, behavioral, environmental, and cultural influences. Regarding diet, an increase in body weight occurs when we take in more calories than we expend. Fats, because they have twice the calories of proteins or carbohydrates, may lead to weight gain if the excess calories are not balanced byphysical activity. But excessive intake of calories from any source—fats, proteins, or carbohydrates—can lead to weight gain.
- Heart disease. A study compared low-fat (12 percent total fat) weight-loss diets to diets with 35 percent monounsaturated fat (healthy fat found in foods such as olive oil and peanut oil) and the equivalent number of calories. The discovery: the diet with 35 percent monounsaturated fats lowered LDL cholesterol and the tendency of forming oxidized LDL, the more dangerous form that increases risks of blocking vessels leading to heart attack or stroke. An example: the traditional diets of Mediterranean populations, which contain high levels of monounsaturated fats, provide protection for the heart.
- Here are tips for making sure your diet is balanced.
- Replace trans fats (check food labels for TFA content) and saturated fats (animal fats such as butter, and fat on meat) with monounsaturated (olive oil, canola, avocados, nuts) and polyunsaturated (safflower, sunflower) fats.
- Try to eat oily fish (salmon, tuna, sardines, mackerel) at least twice a week. These fish are excellent sources of omega-3 fatty acids.
- Choose low-fat dairy products and lean cuts of meat trimmed of fat. Remove the skin from poultry.
- Eat natural sources of fats (nuts, seeds, grains, avocados, fatty fish) to obtain extra nutrients and phytochemicals.
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Source: The Asian Food Information Centre, founded in 1998 and registered in Singapore, is run by a team of scientific, health, and communications professionals who work in close collaboration with the academic and scientific communities in Asia to close the gap between scientific understanding and popular consumer perception on a wide range of food and health topics. Web site: www.afic.org.