Breaking down fats
What's good? What's bad? We wade through the evolving debate
If you can't answer right away, don't worry. You have a lot of company.
According to recent polls, many Americans are dropping low-fat diets for "healthy fat" diets, but only about a third of us can correctly differentiate between so-called good and bad fats.
(By the way, the answers: Polyunsaturated and monounsaturated are good fats, and sources include olive oil, avocados and oily fish.)
But maybe this isn't so surprising, given the flip-floppy advice the nutrition establishment has issued on fats and cholesterol over the years. Remember when avocados and eggs were considered fatty no-nos, while margarine was seen as a healthful alternative? How times have changed.
Though science may have further surprises in store, today's mainstream nutritional advice largely places heart-healthy monounsaturated fatty acids and polyunsaturated fatty acids on the good team and saturated fatty acids and trans fatty acids on the bad. Basically, eat your sardines and olive oil but ditch your fatty burgers and processed snacks made with partially hydrogenated oils.
New research, however, is challenging this simple formula and indicating that some types of saturated fats may actually be neutral to beneficial. Another important finding, according to Harvard University scientist Dariush Mozaffarian: The recent trend in Western diets of replacing saturated fats with refined carbohydrates (such as sugar and white bread) actually makes health worse. They should be replaced, instead, with polyunsaturates (as found in soybean oil and corn oil).
Still, reports from the National Institutes of Health suggest that we need to be choosy about our polyunsaturates, based on their ratio of omega-6 to omega-3. Researcher Joseph Hibbeln says most seed oils (soy, corn, etc.) deliver unhealthy levels of omega-6.
Studies also show that "bad" foods can develop healthier fat profiles depending on what animals are fed and how the fats are processed. Some advocate the healthful consumption of certain animal fats and dairy from pastured animals.
So how can a consumer sort through all of this to simply figure out what foods to eat and avoid? The accompanying charts show where most experts are in agreement, as well as where debates remain on dietary fat and cholesterol.
Of course, your best choices will depend on your cardiovascular health, metabolism, genetics and consultations with your doctor, but here is some information to get you started.
Good fats, bad fats
Sources: Corn, soybean and flaxseed oils, as well as walnuts, flaxseeds and fish. Best sources of omega-3 polyunsaturates are oily fish; plant sources offer smaller levels.
What they do: Lower cholesterol levels and reduce inflammation among other benefits.
The debate: Some scientists caution that seed oils contain too much omega-6 fat at the expense of omega-3 benefits. Others argue that both omega-3 and 6 are beneficial.
Daily recommendation: 8 to 10 percent of calories
Sources: Peanuts, canola, olive oil, avocados, almonds, hazelnuts, pecans and pumpkin seeds
What they do: Improve blood cholesterol levels among other health benefits.
The debate: Their effects when substituted for saturated fats are still being studied.
Daily recommendation: 10 to 25 percent of calories
Sources: Meat, and whole milk dairy as well as coconuts and palm oil
What they do: Raise bad cholesterol levels but also good cholesterol.
The debate: Reductions in saturated fats have not produced better cardiovascular health but have coincided with a rise in obesity. Since many have swapped saturated fats for refined carbohydrates, experts are debating the wisdom of continued reduction recommendations.
Daily recommendations: 10 percent of calories or less
Sources: This plant oil injected with hydrogen is found in stick margarine, some shortening and some processed snacks.
What they do: Lower good cholesterol levels while raising bad.
The debate: None
Daily recommendation: None
Foods to consider
Fat profile: Contain about 5 grams of fat each, of which only about 1.5 grams is saturated.
Pros: Full of protein and other important nutrients.
Cons: Those with cholesterol issues may want to avoid dietary cholesterol found in eggs.
Best version to eat: Pastured chicken eggs contain higher levels of omega-3 than those from indoor chickens.
Fat profile: 55 percent unsaturated, 39 percent saturated
Pros: Can be a good source of vitamin D with less saturated fat than butter.
Cons: Can carry pesticide residues, especially if lard is not organic.
Best version: Pastured, organic pig lard with higher levels of omega-3s
3. Coconut oil
Fat profile: 87 percent saturated, 8 percent unsaturated
Pros: Unprocessed, virgin coconut oil is trans-fat-free and relatively low in calories and it contains high levels of lauric acid that experts consider neutral to beneficial.
Cons: Hydrogenated versions — most often studied in the past and found in processed foods — can raise bad cholesterol.
Best version: Virgin coconut oil
4. Avocados Fat profile: 75 percent monounsaturated, 16 percent saturated
Pros: Good source of vitamin E, protein, fiber, folate and other nutrients
Cons: High in calories
Best version: Any
Note: Because these recommendations for percentage of fat calories are from varied sources, taken together they can exceed official government dietary guidelines.
Sources: U.S. Department of Agriculture, Harvard School of Public Health, "Good Fats" and Centers for Disease Control and Prevention.