Document Type : Review Article
Student Research Committee, School of Nutrition and Food Sciences, Shiraz University of Medical Sciences, Shiraz, Iran
Cardiovascular Research Center, Shiraz University of Medical Sciences, Shiraz, Iran
Baqiyatallah University of Medical Sciences, Tehran, Iran
Department of Clinical Nutrition, School of Nutrition and Food Sciences, Shiraz University of Medical Sciences, Shiraz, Iran
Overweight and obesity are the causes of many diseases. One of the most important and modifiable factors in obesity is dietary changes. Fats are macronutrients that provide more calories than proteins and carbohydrates; therefore, they are blamed for the accumulation of fat mass in the body. Different types of fatty acids have been shown to have different metabolic responses. There is no definite consensus on the effect of different types of fatty acids on body composition, but a review of the literature shows that different fatty acids have important differences in accumulation of adipose tissue. Monounsaturated fatty acid (MUFA) levels of more than 12% of calories in weight loss diets have been significantly associated with further reduction of adipose tissue. Higher blood levels of alpha linolenic acid (n-3) and gamma linoleic acid were inversely associated with weight gain. There is a significant inverse relationship between PUFA/SFA and MUFA/SFA levels and waist circumference and consity index. Methylation of adiponectin gene is altered by overuse of saturated fatty acids (SFAs). SFAs and trans fatty acids (TFAs) have lower oxidation rates than polyunsaturated fatty acids (PUFAs) and MUFAs. This feature makes them more inclined to save. Replacing SFA and TFA with MUFA and PUFA can reduce the accumulation of adipose tissue and maintain more lean body mass. Although it is recommended that about 30% of dietary calories to be obtained from fats, the exact share of each of these fatty acids in diet to achieve the desired results has not been determined, yet.