Fortunately, researchers, health professionals and even many consumers are now putting more emphasis on the quality of dietary fat instead of its quantity. The 2015 Dietary Guidelines for Americans, the American Heart Association and other organizations recommend a limit of 5 to 10 percent of total calories to come from saturated fat and suggest replacing some saturated fatty acids with unsaturated fatty acids. Additional information comes from a 2014 systematic review of Nordic research, which examined the effects of dietary fats on various measures of cardiometabolic disease risk. Below is a brief summary.
Similar to other studies, the Nordic review found convincing evidence that partial replacement of saturated fatty acids with polyunsaturated or monounsaturated fatty acids lowers both total and LDL-cholesterol levels. Eight of nine studies reviewed found such an effect. The authors noted no effect on serum triglycerides and were unable to make a conclusion regarding HDL-cholesterol concentrations.
Though there were only a few studies and a total of 229 subjects in the insulin sensitivity studies, the authors concluded there was probable evidence that when monounsaturated fatty acids replace saturated fatty acids, insulin resistance improves. They also found probable evidence for lower fasting insulin concentrations. Additionally, the American Diabetes Association recommends that people with diabetes replace trans fatty acids and some saturated fatty acids with unsaturated fatty acids.
Though two randomized controlled trials found that a diet enriched in monounsaturated fats and restricted in saturated fats resulted in lowered blood pressure, the overall evidence for an association between total fat, type of fat and blood pressure was limited-no conclusion.
The Nordic review found probable evidence for a moderate direct association between total fat intake and body weight. There were no conclusions regarding waist circumference. However, other emerging research suggests that both canola oil and high oleic canola oil may reduce abdominal adipocity when compared to other healthful plant oils.
Counseling Patients and Clients
Though more of my patients are hip to the benefits of unsaturated fats, many still come in hesitant and with questions. I find that giving them actionable and positive messages empowers them to make good choices in the supermarket, the kitchen and when eating away from home. I use my Good Fats 101™ Shopping List and my Good Fats 101 Try This, Not That Cards. Together we search for recipes, review food labels and create a sample menu. I make simple suggestions such as these:
- Spread mashed avocado or almond butter on whole grain toast.
- Snack on a half of a peanut butter sandwich instead of a bologna sandwich.
- Cook up salmon, barramundi or other fatty fish at least twice weekly.
- Sprinkle nuts instead of croutons onto salads.
- Substitute all or half of the butter in your recipe with canola oil.
- When baking, replace 4 tablespoons of butter with 3 tablespoons of canola oil.
- Schwab U, et al. Effect of the amount and type of dietary fat on cardiometabolic risk factors and risk of developing type 2 diabetes, cardiovascular diseases, and cancer: a systematic review. Food & Nutrition Research 2014, 58: 25145.
- Evert AB, Boucher JL, Cypress M, et al. Nutrition therapy recommendations for the management of adults with diabetes. Diabetes Care 2014;37(Suppl. 1):S120–S143.