Research continually provides us with valuable information about associations between the foods we eat and our health. One component of food that we’re learning a great deal about is fat.  

Over the years, scientific research has shown that all fats are not created equal and that not only do you need fat in a healthy diet but some fats are quite healthy and help reduce your risk of developing heart disease.
 

The Fat – Health Link
High total fat intakes have not been directly linked to obesity or any other chronic disease.  Rather, by consuming high levels of total fat you may run the risk of consuming too much saturated fat (“bad” fat) and/or too many calories (fat has 9 calories per gram).  The 2005 Dietary Guidelines recommend keeping total fat intake between 20-35% to keep saturated fat and calories within recommended limits.
Source: Hu, FB., et al., Dietary fat intake and the risk of coronary heart disease in women. N Engl J Med 1997;337;1491-1499.  2005 Dietary Guidelines Advisory Report.  

Also, a recent large scale clinical trial showed that reducing total fat intake to 28.8% of total calories did not reduce heart disease or cancer risk in postmenopausal women.  Investigators suggest the type of fat in the diet versus lowering total fat intake is more important when trying to reduce the risk of coronary heart disease.  The risk for cardiovascular disease is more strongly related to the dietary intake of trans and saturated fatty acids than to total dietary fat intake.
Source: Howard BV., et al., Low-fat dietary pattern and risk of cardiovascular disease: the Women’s Health Initiative Randomized Controlled Dietary Modification Trial. JAMA. 2006;295(6):655-66.

And yet another recent study found that replacing a certain percentage of carbohydrate in the diet with unsaturated fats significantly reduced blood cholesterol levels and blood pressure.
Source: Appel LJ., et al., Effects of protein, monounsaturated fat, and carbohydrate intake on blood pressure and serum lipids: results of the Omni Heart randomized trial. JAMA. 2005; 294(19):2497-8.

THE TYPE OF FAT YOU EAT IS MORE IMPORTANT THAN HOW MUCH FAT YOU EAT!

Knowing how certain fats affect blood cholesterol is the first step in lowering your risk for heart disease. Monounsaturated and polyunsaturated fats have been shown to lower total and LDL (“bad” cholesterol).  On the contrary, saturated fat and trans fat have been shown to raise LDL cholesterol and trans fat also lowers HDL cholesterol, which can increase your risk for heart disease.  By incorporating a variety of fats and oils into your diet, you can achieve a balance of unsaturated fats and reduce your risk for cardiovascular heart disease. 
Source: Gardner, C and Kraemer, H. Monounsaturated fat versus polyunsaturated fat and serum lipid. Arteriosclerosis, Thrombosis, and Vascular Biology. 1995;15:1917-1927.

 What the Experts Say
“Considerable recent research, including controlled feeding and epidemiological studies, has provided pretty good evidence that replacing saturated and trans fats with mono- and poly-unsaturated fats can significantly reduce important health risks. According to some studies, this substitution can potentially reduce the risk of heart disease by up to 30-40 percent.” 
-- Mark B McClellan, MD, PhD Commissioner, Food and Drug Administration. July 1, 2003