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Over the past several years, research has shone new light on the role of dietary fats as part of a healthful eating pattern. As it is now understood, some types of fats may actually enhance health.
This IFIC Review provides a look at the latest nutrition research and recommendations on dietary fats and fatty acids as well as innovations in food science designed to deliver products to help consumers meet recommendations of health professionals.
Fat—The Nutrient
Dietary fat is an essential nutrient required for many functions in the body.
Like carbohydrates and protein, fat is a source of energy, or calories, for the body. Fat is the most concentrated source of energy in the diet, and provides nine calories per gram compared with four calories per gram from either carbohydrates or protein. Fat is a particularly important source of energy for infants and young children; approximately 55 percent of the calories in human breast milk come from fat1. Dietary fat also supplies linoleic and linolenic acids, the essential fatty acids, which contribute to proper growth.
Fat is required for maintaining healthy skin, regulating cholesterol metabolism, and as a precursor of prostaglandins, hormone-like substances that regulate many body processes. Fat is also needed to carry fat-soluble vitamins A, D, E and K, and carotenoids to aid in their absorption by the intestines. Because fats are digested slowly, they may play a role in satiety or signals of fullness the body receives after eating.
Some fat is found in blood plasma and other body cells, but the largest amount is stored in the body's adipose, or fat, cells. These adipose tissues not only store energy, but also serve to insulate the body by supporting and cushioning organs.
Fatty Acids—Structure and Functions
Technically, we should refer to "fats" in the plural, since there is not just one type of "fat." Fats are composed mostly of the same three elements as carbohydrates—carbon, hydrogen, and oxygen. However, fats have relatively more carbon and hydrogen and less oxygen, thus supplying the higher energy value of nine calories per gram.
Fats are actually combinations of many different fatty acids, the building blocks of fats, which each exert characteristic physiological and metabolic effects. One molecule of a fat can be broken down into three molecules of fatty acids and one molecule of glycerol. Thus, fats are known chemically as triglycerides.
Fatty acids are generally classified as saturated, monounsaturated or polyunsaturated. These terms refer to the number of hydrogen atoms attached to the carbon atoms of the fatty acid chain. Polyunsaturated fats are further distinguished by the number of carbons contained in their acid chain designated by the location of the double bond, also known as the “omega” method of classification (omega-3 and omega-6). For example, the omega-3 fatty acids are classified as having the double bond at the third carbon from the methyl group.
Fats in foods contain both saturated and unsaturated fatty acids. In general, fats containing a majority of saturated fatty acids are solid at room temperature, although some solid vegetable shortenings are up to 75 percent unsaturated. Fats containing mostly unsaturated fatty acids are usually liquid at room temperature and are called oils.
For a list of common saturated and unsaturated fatty acids, their chemical structure, and source in the diet, see chart.
Fats are important ingredients in many foods because of their functional properties. In many recipes, fats enhance the taste, aroma, and texture of food. Saturated fatty acids are more stable than unsaturated fatty acids because of their chemical structure. Stability is important to prevent rancidity and off flavors or odors.
Dietary Fats in the Diet: A Moderate Approach … Not Just Focused on Heart Disease
In the past, dietary guidance recommended diets low in total fat to decrease the risk for heart disease. According to the National Heart, Lung, and Blood Institute (NHLBI), more than 12.5 million Americans suffer from coronary heart disease (CHD) and more than 500,000 die from CHD each year2. But the latest research now recommends consuming a moderate amount of dietary fat for overall good health, including heart health.
The 2005 Dietary Guidelines for Americans recommend a total fat intake between 20 and 35 percent of calories for adults to meet daily energy and nutritional needs while minimizing risk of chronic disease. Most fats in the diet should come from sources of polyunsaturated and monounsaturated fats such as fish, nuts, and vegetable oils3.
Consuming less than 20 percent of calories from fats may decrease desirable high-density lipoprotein (HDL) cholesterol. Low intake levels of dietary fats can also lead to inadequate intakes of vitamin E and essential fatty acids1, 4. Consuming more than 35 percent of calories from fats generally increases saturated fat intake and may make it more difficult to avoid consuming excess calories1, 4.
The 2005 Dietary Guidelines for Americans recommend a fat intake of 30 to 35 percent of calories for children two to three years of age, and 25 to 35 percent of calories for children and adolescents four to 18 years of age. Restricting fat intake is not recommended for infants less than two years of age because high energy intakes and essential fatty acids are required to support rapid growth and development5.
According to the Continuing Survey of Food Intakes of Individuals (CSFII), the median intake of total fat in the United States ranges from about 32 to 34 percent of total calories6. Major contributors of dietary fats include butter, margarine, vegetable oils, visible fat on meat and poultry, whole milk, egg yolks, nuts, and baked goods1.
Dietary Cholesterol
Cholesterol is not a fat, but rather a fat-like substance classified as a lipid. Cholesterol is vital to life and is found in all cell membranes. It is also necessary for the production of bile acids and steroid hormones. Most cholesterol in the blood is manufactured by the body, at a rate of about 800 to 1,500 milligrams per day.
The 2005 Dietary Guidelines for Americans recommend that healthy people consume less than 300 mg of cholesterol daily3. Dietary cholesterol is found only in animal products such as organ meats, egg yolks, meats, chicken, and shellfish. Vegetable oils and shortenings are cholesterol-free.
A Primer on Blood Cholesterol and Coronary Heart Disease
Although diet is important, it is just one factor influencing blood cholesterol levels. Many experts suspect that dietary influences on serum cholesterol may be more complex than just the cholesterol and fatty acid content of the diet alone. For some people at risk, family history could be a stronger predictor of cholesterol levels than diet. Regardless of how little fat or cholesterol these individuals consume, their bodies produce excess amounts of serum cholesterol, which is unhealthful. Scientists are already beginning to identify the gene or phenotype that is carried by such "cholesterol responsive" individuals.
Risk factors beyond control include age, race, and gender. But there are many heart disease risk factors that individuals can influence. These include maintaining a healthy weight, getting adequate physical activity, controlling high blood pressure, avoiding cigarette smoking, and managing stress. For those with diabetes, controlling blood glucose levels is also important.
The NHLBI developed the Adult Treatment Plan III (ATP III) guidelines, which prescribe Therapeutic Lifestyle Changes (TLC) to help cut the risk of heart disease. The guidelines recommend a low-cholesterol eating plan with less than 200 mg of dietary cholesterol per day2.
| Facts about Blood Cholesterol Cholesterol in the body travels through the blood via particles called lipoproteins—combinations of lipids and proteins. Lipids are a form of fat inside the body. Blood cholesterol reflects the amount of three major classes of lipoproteins: very-low-density lipoprotein (VLDL); low-density lipoprotein (LDL), which contains most of the cholesterol found in the blood; and high-density lipoprotein (HDL). LDL is thought to be the culprit in coronary heart disease (CHD) and is associated with cholesterol deposits on artery walls that aid in the development of atherosclerosis, or hardening of the arteries, which can lead to a heart attack. In contrast, HDL is seen as desirable. Studies suggest that the more HDL in the blood, the lower the risk of developing CHD. HDL is thought to carry cholesterol out of the blood and back to the liver for breakdown and excretion. |
The ATP III guidelines, which identify LDL cholesterol as the primary target of therapy, classify levels of total, LDL, and HDL cholesterol as follows:
| Total Cholesterol Level Less than 200 mg/dL
200-239 mg/dL
240 mg/dL and above
| Total Cholesterol Classification Desirable
Borderline high
High
|
LDL Cholesterol Level
Less than 100 mg/dL
100-129 mg/dL
130-159 mg/dL
160-189 mg/dL
190 mg/dL and above
| LDL Cholesterol Classification Optimal
Near optimal/above optimal
Borderline high
High
Very high
|
HDL Cholesterol Level
Less than 40 mg/dL
60 mg/dL and above
| HDL Cholesterol Classification Low
High
|
Dietary Fats and Obesity
The prevalence of overweight and obesity has increased markedly over the last two decades in the United States7. Overweight and obesity are caused by many factors. Much like blood cholesterol, an individual’s body weight is determined by a combination of genetic, metabolic, behavioral, environmental, cultural, and socioeconomic influences. Being overweight or obese increases the risk of many diseases and health conditions, including hypertension, diabetes, stroke, and some cancers8. For most people, weight gain is a product of excess calorie (energy) consumption and/or inadequate physical activity9.
Human investigations into the role of a high-fat diet in obesity do not single out dietary fats as a culprit independent of energy intake, although individuals are recommended not to exceed 35 percent of calories from fat as it may increase the risk for excess energy consumption1, 4. Practically, as the percent of calories from fats has declined in the U.S. diet, there is no evidence that body weight has declined. Further, diets in many European countries contain more calories from fat than in the U.S., but people in these countries generally experience lower rates of obesity. Over-consumption of any calorie-containing nutrient, such as protein, fat, carbohydrate or alcohol, can contribute to the development of obesity and therefore should be managed.
A review of short-term and long-term intervention studies on normal weight and moderately obese subjects generally indicates that significant reductions, of more than four percent, of calories consumed from fats result in small losses in body weight1. Long-term studies comparing high-fat and high-carbohydrate diets of equal caloric value fail to show high-fat diets contributing to weight gain to a greater or lesser extent than high-carbohydrate diets10. However, the National Weight Control Registry, a large prospective investigation of long-term successful weight loss maintenance, found that many obese subjects in their database maintained weight loss over one to two years by following a low-calorie, low-fat eating plan11.
Dietary Fats and Cancer
Through an evidence-based review of the literature and positions of other expert groups, the Dietary Guidelines Advisory Committee concluded that the “evidence between total fat intake and certain cancers is suggestive but not conclusive12.” Data suggest that diets low in folate and calcium and high in total fat, calories, meat, and alcohol are the associated with an increased risk of developing colorectal cancer, and that dietary fat from animal sources may be linked to a higher risk of prostate cancer13. Current research shows that dietary fat intake in general does not seem to be associated with risk of breast cancer14.
One of the questions that remains is whether associations noted between dietary fats and risk for developing cancer are correlated with the amount of fat, attributable to the type of fatty acid, or related to some other factor in food. Exploring the relationship between cancer and specific types of fats is an important area of current research14.
A Look at Different Types of Fatty Acids and Health
Unsaturated Fats
Monounsaturated and polyunsaturated fatty acids are unsaturated fats. When they replace saturated fats in the diet, they help reduce blood cholesterol levels and thus lower the risk of heart disease. The 2005 Dietary Guidelines for Americans and MyPyramid food guidance system recommend that most fat consumption come from sources of polyunsaturated and monounsaturated fatty acids such as fish, nuts, and vegetable oils3, 15.
Canola, olive, and high oleic safflower oils, and nuts are rich in monounsaturated fats. Intakes of monounsaturated fats for different age and gender groups range from 13.6 to 14.3 percent of energy16.
Two polyunsaturated fatty acids, alpha-linolenic acid (an omega-3 fatty acid) and linoleic acid (an omega-6 fatty acid), are known as essential fatty acids because they are essential for body function, but the body cannot synthesize them, so they must be consumed from food sources. A lack of either fatty acid results in deficiency symptoms such as scaly skin and dermatitis, but deficiencies are extremely rare in the United States and Canada. Recommended intakes for alpha-linolenic acid are 1.6 and 1.1 grams per day for men and women, respectively. Recommended intakes for linoleic acid are 17 and 12 grams per day for men and women, respectively1.
Omega-3 Fatty Acids and Reducing Risk of Chronic Disease
Two omega-3 fatty acids, eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), are found in all fish and shellfish. Oily fish from cold waters, such as salmon, mackerel, tuna, and trout are especially rich in EPA and DHA. Consuming two servings per week, approximately eight ounces, of fish high in EPA and DHA is associated with cardioprotective effects such as reduced risk of sudden death and death from coronary heart disease in adults. Further research is needed to determine whether other sources of EPA and DHA provide similar benefits4.
A small clinical trial found that patients who were given fish oil concentrate for two years had lower triglyceride levels and minimal artery blockage when compared to those receiving a placebo17. This trial showed that consuming omega-3 fatty acids daily may reduce the risk of abnormal thickening of arteries due to fatty deposits on arterial inner walls, more commonly known as atherosclerosis. A meta-analysis of studies on diabetes and fish oils found a 30 percent reduction in patient triglyceride levels—particularly among subjects with type 1 diabetes18. This is noteworthy, considering that the high cardiovascular mortality rate of people with diabetes has been partially attributed to increased triglyceride concentrations in the blood.
Emerging evidence also suggests benefits from omega-3 fatty acid consumption in health conditions such as depression, cancer, lupus, and asthma19-22.
To a limited extent, humans can convert alpha-linolenic acid, the plant source of omega-3 fatty acids, into EPA and DHA in the body. Alpha-linolenic acid also appears to confer cardioprotective benefits, although evidence is strongest for EPA and DHA. There is no evidence of a beneficial effect of alpha-linolenic acid intake on incidence of stroke3. Further research is needed to determine whether there is an association between alpha-linolenic acid and risk of prostate cancer and, if so, what this association is23-24.
Omega-6 Fatty Acids and Reducing Risk of Chronic Disease
Research shows that an intake of omega-6 fatty acids between five to ten percent of calories is associated with a most favorable lipid profile to reduce coronary heart disease risk and may decrease coronary heart disease mortality4. Mean intakes of omega-6 fatty acids by adults are approximately five to six percent of total energy intake25.
Much of the research conducted to determine whether there is an association between dietary fats and cancer risk has examined unsaturated fats intake, specifically linoleic acid. Yet there is not a clear consensus about unsaturated fatty acids or linoleic acid intake and cancer risk.
Saturated Fats
Meats, baked goods, and full-fat dairy products are the main sources of saturated fats in most diets. Coconut, palm, and palm kernel oils are also largely comprised of saturated fats. This section contains information on different types of saturated fats in the diet and their effect on health.
Saturated Fats and Heart Disease
Hundreds of studies have examined the effect of saturated fats on blood cholesterol levels. High intakes of saturated fats can raise the level of total cholesterol and low-density lipoprotein (LDL) cholesterol in the blood, and increase risk for coronary heart disease1. A reduction in calories from saturated fats by one percent decreases LDL cholesterol by an average of one to two percent.
The NHLBI ATP III treatment plan and the 2005 Dietary Guidelines recommend a low saturated fat diet calling for less than seven to ten percent of total calories coming from saturated fat2-4. Currently, saturated fats provide approximately 11 to 12 percent of calories in adult diets6.
Not All Saturated Fatty Acids are Created Equal—The Stearic Acid Story
Nearly 40 years ago, researchers first noticed the different effects of saturated and polyunsaturated fats on blood cholesterol. In the early 1950s, scientists observed that diets rich in unsaturated vegetable fats resulted in lower levels of blood cholesterol than diets rich in the more saturated animal fats.
Historically, two equations that predict the effect of dietary modifications on blood cholesterol levels have shown that saturated fats significantly raise cholesterol levels1. However, researchers also found that not all types of saturated fatty acids fit the predictive equation.
For example, fats rich in stearic acid (C18) were found to have a neutral effect on blood cholesterol. One equation also indicated that saturated fatty
acids with shorter carbon chains (C6-C12) did not raise cholesterol. Additionally, one equation identified myristic acid (C14) as the most hypercholesterolemic of the saturated fatty acids, and the other equation identified palmitic (C16) as the most hypercholesterolemic26-27.
Over the last four decades, the neutral effect of stearic acid on total and LDL blood cholesterol levels has been confirmed in animal and human studies26-31. In fact, a meta-analysis of 35 studies suggests that stearic acid has a minimal effect on LDL cholesterol and no effect on HDL cholesterol, while the other long chain saturated fatty acids increase both LDL cholesterol and HDL cholesterol32. Further study is needed to assess the potential impact of stearic acid intake on cardiovascular disease risk factors other than blood lipids (i.e., inflammation and thrombosis)1,12.
In light of the findings about stearic acid, some researchers recommend no longer grouping it with cholesterol-raising saturated fatty acids.
Saturated Fats and Cancer
As stated previously, the association between the development of breast cancer and dietary fats in general is thought to be weak, however, a meta-analysis of 45 case-control and cohort studies published in 2003 suggests that a higher intake of saturated fats was significantly associated with breast cancer risk, while monounsaturated fats and polyunsaturated fats were not33. However, earlier findings from the Nurses’ Health Study found no evidence that lower intake of saturated fats was associated with a decreased risk of breast cancer14.
Trans Fatty Acids
Trans fatty acids are found naturally occurring in beef, lamb, and dairy products. They are also formed in partially hydrogenated vegetable oils and are found in foods such as cookies, crackers, pastries, and fried foods.
Trans Fatty Acids and Risk of Chronic Disease
Scientific evidence indicates that diets high in trans fatty acids may increase the risk of heart disease by increasing total and LDL cholesterol levels. Some studies also indicate that increased intake of trans fats may decrease HDL cholesterol levels. An extensive review of the research can be found in Section 4 of the 2005 Dietary Guidelines Advisory Committee Report available at: http://www.health.gov/dietaryguidelines/dga2005/re port/HTML/D4_Fats.htm4.
According to the Institute of Medicine Dietary Reference Intakes report, trans fatty acids are not essential and provide no known health benefit1. Therefore, the 2005 Dietary Guidelines for Americans and other health authorities recommend keeping consumption as low as possible while consuming a nutritionally adequate diet3. A 1999 studied showed the mean trans fatty acid intake in the U.S. is 2.6 percent of calories, and it is estimated that 20-25 percent of trans fatty acids in the diet come from naturally occurring sources25.
| Naturally Occurring Trans Fatty Acids— Special Health Benefits? Conjugated linoleic acid (CLA) and vaccenic acid are types of trans fatty acids naturally present in dairy products, beef, and lamb. Emerging evidence from animal studies suggests that CLA decreases fat deposition and body lipid content34. However, limited human studies have not confirmed these findings. Animal studies also suggest that CLA protects against the development and progression of atherosclerosis35. Both animal and laboratory studies show that CLA and vaccenic acid exhibit anti-carcinogenic effects against many types of cancer36-38. |
The Food Science Behind Reformulated Fats
This section begins with an overview of the hydrogenation process and discusses the efforts of food scientists as they develop new products with fat profiles that meet new nutrition recommendations.
What is Hydrogenation?
Hydrogenation is the process of adding hydrogen atoms to points of unsaturation in fat molecules, making them more saturated. The process is conducted by reacting hydrogen gas with oil at elevated temperature and pressure in the presence of a catalyst.
Hydrogenation is used to convert liquid oils to a semi-solid or solid form for greater functionality in foods. For example, vegetable oils are often partially hydrogenated to produce solid shortenings or margarines, to provide textural properties in many foods, and increase the stability of a fat or oil, which is important in cooking and extending a product’s shelf life.
Fats have a tendency to break down or oxidize when exposed to air and heat over time. Oxidized fats impart a rancid flavor and undesirable odor. By adding hydrogen atoms, the fatty acids become more stable and resistant to oxidation. This stability is especially important for fats used in deep-fat frying.
Extent of Hydrogenation
The hydrogenation process is easily controlled and can be stopped at any desired point. The amount of trans fat in a product is highly variable and is dependent on the degree of hydrogenation. If the hydrogenation of a vegetable oil, for example, is stopped after only a small amount of hydrogenation has taken place, the oils remain with very small amounts of trans fatty acids in them. Further hydrogenation can produce soft but solid appearing fats that contain a greater amount of trans fatty acids, and are often used in solid shortenings and margarines.
Fully hydrogenated oils are solid at room temperature, and because the unsaturated fatty acids have largely become saturated, they contain no trans fatty acids.
The hydrogenation of oils rich in linoleic acid (a polyunsaturated fat) and oleic acid (a monounsatu-rated fat) result in the formation of oleic acid and stearic acid, respectively. Oleic acid has been found to have a lower effect on blood cholesterol levels when compared to saturated fats. And unlike other saturated fatty acids, stearic acid does not appear to raise blood cholesterol levels.
Hydrogenation and Trans Fatty Acids
Scientists often discuss hydrogenation in terms of “cis” versus “trans” fatty acids. The phrase “cis” describes the typical configuration of hydrogen atoms in unsaturated fatty acids, which are located on the same side of the carbon-to-carbon double bond.
During hydrogenation, some hydrogen atoms move to the opposite side of a double bond. This newly formed configuration of fatty acids is referred
to as “trans,” meaning “on the other side of.” Trans fatty acids contain at least one double bond in the trans configuration. The position of a carbon-to-carbon double bond within the fat molecule also may change.
Partially hydrogenated vegetable oils contain trans fatty acids. Trans fatty acids have physical properties generally resembling saturated fatty acids, and their presence tends to harden oils and prevent rancidity by contributing to their stability.
| Alternatives to Trans Fat in the Food Supply Scientists continue to look for ways to provide trans fatty acid—or “trans fat”—alternatives to help consumers meet recommendations of the 2005 Dietary Guidelines for Americans. Scientists face challenges in bringing acceptable alternatives to consumers that are lower in or free of trans fats, as well as lower in saturated fats. Trans fat replacements must provide the same functional characteristics such as texture, crispness, appearance, and stability of the product being replaced, while also remaining cost effective and abundant for use. Four major types of trans fat alternatives are currently on the market: Stable oils and fats. The most common oils that are relatively stable are palm, corn, and cottonseed oils. They require little or no partial hydrogenation for most food product applications and, thus, contain no trans fats. Used to a lesser extent are palm kernel, coconut, high oleic canola, high oleic sunflower, mid and high oleic sunflower, and low linolenic soybean oils, and animal fats (e.g., beef tallow and lard). Trait enhanced oilseed varieties (e.g., low linolenic soybeans), providing increased stability in oils, are also available in the marketplace. Interesterified oils and fats used as shortening. The interesterification process rearranges the fatty acids in a blend of oil and solid resulting in customized melting characteristics. Modified partially hydrogenated oils. Alteration of the variables influencing the hydrogenation process, such as time, pressure, temperature, or catalyst, can result in a partially hydrogenated product with a significantly reduced trans fat content. Fully Hydrogenated. This process completely saturates the fatty acids from vegetable oils resulting in the presence of little to no trans fatty acids. The dominant saturated fatty acid formed from the full hydrogenation vegetable oil is stearic acid. Other trans fat alternatives may arise as food scientists continue to further their research. |
Fats of the Future: Food Science Meets Nutrition
The results of fatty acid research, both in terms of health and functionality, are likely to have practical applications for food scientists. Changing the fatty acid profile of oils is a likely beginning. In fact biotechnology is now being used to develop canola plants to produce oil with increased levels of stearic or oleic acids for use in soft margarine products and confectionary production.
Some researchers see the structure of individual triglycerides, as opposed to the fatty acid composition of oils, as the next frontier. Every triglyceride, or fat, contains three fatty acids. The rearrangement of these three fatty acids within a triglyceride molecule potentially could affect the atherogenic potential of such a fat. Scientists continue to search for the best dietary fatty acid profile for health promotion.
The science that drives nutrition recommendations regarding the effects of dietary fats on health is complex and continuously evolving. So, too, is the science and technology used to reformulate food products based on these new recommendations. Sometimes the science and technology that drive product reformulation cannot evolve quickly enough to create products with both the latest “desired” nutrient profile and the ability to meet consumer preference.
The evolving research behind dietary fats dietary fats offers a great opportunity for nutrition scientists and food scientists to work in concert to deliver nutrition recommendations that promote health and food products that deliver on those recommendations.
Fats in the Marketplace
When it comes to fats, the nutrition policy community is now researching and regulating other fatty acids in addition to total fat, saturated fats, and unsaturated fats. For instance, to assist consumers in monitoring their intake of trans fatty acids, the Food and Drug Administration as of 2006, requires manufacturers to list trans fat on Nutrition Facts panels and some Supplement Facts panels. Consumers can use this information, along with both health claims that meet significant scientific agreement (SSA) and those that are “qualified,” on food packaging to make more informed choices about products before purchase.
Health claims are an example of a label education tool regulated by the Food and Drug Administration (FDA). They appear on food packages to aid the consumer with additional nutrition information about health effects of that specific food. These claims display the strength of scientific evidence representing the relationship between a food component and a disease or health-related condition39. Health claims have historically focused on foods low in fat, saturated fats, and cholesterol and the potential to reduce the risk of coronary heart disease or some cancers40.
“Qualified” health claims, which characterize the level of scientific evidence linking a specific food component or food to a disease or health-related condition, are more common as additional science becomes available on individual fatty acids and their impact on health. After evaluation of research on two fatty acids, the FDA released two qualified health claims for EPA/DHA and olive oil. The qualified health claims are in reference to their possible beneficial effects of reducing the risk of coronary heart disease41-42.
Dietary Fats—From Science to the Plate
Much is yet to be learned about the roles of different fatty acids in terms of both health promotion and risk for some chronic diseases. As research continues to unfold, the 2005 Dietary Guidelines for Americans and USDA’s MyPyramid food guidance system represent the best advice for incorporating dietary fats and cholesterol into a healthful eating plan3,15.
These guidelines are only one aspect of good nutrition. Variety, moderation, and balance of all foods are the most prudent approach for the general population. Moreover, eating a well-balanced diet while getting plenty of physical activity, maintaining a healthy weight, avoiding smoking, and controlling diseases such as heart disease and diabetes continues to be the best approach to a healthful lifestyle.
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