How much fat should I eat per day?

Fat serves important functions in the human body such as providing insulation, cushioning your organs, manufacturing hormones and aiding in the absorption and transportation of the fat-soluble vitamins. Most individuals mistakenly think that all fat is bad and should be cut from the diet. Fat aids in satiety, or promotes a feeling of fullness, and gives many foods flavor, juiciness and flakiness. You should pay more attention to choosing foods that contain healthy unsaturated fatty acids and controlling the quantity you consume than omitting fats all together.

How much fat do I need per day?

Although fat is an essential nutrient that provides energy in the form of calories, there is not a set Recommended Dietary Allowance (RDA) or Recommended Adequate Intake (AI) level for total fat. There are, however, AI levels for two specific polyunsaturated fatty acids, linoleic acid, known commonly and collectively as the omega-6 fatty acids, and α-linolenic acid, or the omega-3 fatty acids. Most Americans consume too much linoleic acid and not enough α-linolenic acid. The AI for omega-6 fatty acids is 17g/day for men and for women, 12g/day. The AI for α-linolenic acid is 1.6g/day for men and 1.1g/day for women.

You should eat some fat every day to avoid deficiencies of these fatty acids. Omega-3 fatty acids, in particular, are essential for brain development and eyesight in infants. They also may promote heart health and reduce inflammation. Excellent food sources of omega-3 fatty acids are seafood, canola oil, walnuts, soybeans and flaxseeds. Since most Americans consume too much fat overall, especially saturated and trans fats, aim to limit your total fat intake to about 30% of calories. On a 2,000-calorie diet, that would be about 66g.

How much fat per day is healthy?

The Institute of Medicine Food and Nutrition Board suggests an Acceptable Macronutrient Distribution Range for total fat intake to be between 20 and 35% of your total calories with an emphasis on foods rich in poly- and monounsaturated fats. No more than 10% of your total calories should come from unhealthy saturated and trans fats. This range was set to limit chronic diseases associated with a high fat diet, such as heart disease.

Can you explain trans versus saturated fats?

Saturated fats describe a group of naturally occurring fatty acids that are mostly solid at room temperature. Food products particularly rich in saturated fats include poultry skin, cheese, whole milk, premium ice cream, fatty meat/regular ground meat, butter and cream. Saturated fat intake should be limited to 10% or less of total calories.

Trans fatty acids are found naturally in small amounts in some meats and dairy products but the most harmful trans fats are man-made. They have been used in processed foods to give these items the consistency, texture and shelf-life of those made with saturated fats. Trans fats are not essential and provide no known benefits to human health. Therefore, there is no recommended intake. In fact the American Heart Association recommends limiting total trans fat intake to 2g or less daily, 0g is best.

Foods rich in trans fats include household shortening, regular stick margarine, fried foods and many baked goods. With most types of saturated fatty acids and trans fats, there is a positive linear trend between amount consumed, LDL cholesterol concentration, and risk of developing coronary heart disease.

How much fat is in whole milk?

Whole milk refers to cow’s milk that contains approximately 3.5% fat. It is higher in total fat and calories than low-fat or skim milk. Unfortunately, much of the fat in whole milk is saturated. An 8-oz. glass of whole milk, a standard serving, provides about 150 calories and 8 grams fat. Over half of the amount of total fat, 4.5g, is saturated. For perspective, on a 2,000-calorie diet, 10% of calories from saturated fat comes out to about 20g for the day. One cup of whole milk meets nearly 25% of your daily limit for saturated fat.

REFERENCES

• Food and Nutrition Board. Dietary Reference Intakes for Energy, Carbohydrate, Fiber, Fat, Fatty Acids, Cholesterol, Protein, and Amino Acids (Macronutrients) (2005). Chapter 8: Dietary Fats: Total Fat and Fatty Acids (422-541). Available at: http://www.nap.edu/openbook.php?record_id=10490&page=422
• AH Lichtenstein and L Van Horn. American Heart Association Science Advisory: Very Low-Fat Diets. Circulation. 1998;98: 935-939.
• J Anderson et al. Colorado State University Extension: Nutrition for the Athlete (12/10): http://www.ext.colostate.edu/pubs/foodnut/09362.html
• Atkins Diet: Program Overview. http://www.atkins.com/Program/ProgramOverview.aspx
• U.S. Department of Agriculture National Nutrition Database for Standard Reference: http://www.nal.usda.gov/fnic/foodcomp/search/