Quantcast
Insights/Opinion
A mix of fats, such as those found in nuts, avocados, salmon and olives, could be healthy and more satisfying. a_namenko / iStock / Getty Images Plus

Learn to Balance Fats for a Healthier Diet, Researcher Argues

By Heidi Silver

Public health guidelines, such as the Dietary Guidelines for Americans, have long emphasized reducing dietary fat intake, but nutritionists and other health scientists now have more recent evidence that not all fats have adverse effects. Dietary fats differ with regard to their effects on health and risk for chronic diseases, particularly in regard to effects on risk for heart disease.

Indeed, some nutrition experts now believe that certain types of dietary fat may even reduce cardiovascular risk. Some dietary fats may lower fats in the blood called triglycerides. They may also increase levels of HDL, or what is known as the "good" cholesterol, and reduce LDL-cholesterol, or the less healthy type of cholesterol, thus improving the HDL to total cholesterol ratio.


Also, many diet plans that do not strictly limit the total amount of dietary fat a person consumes have been associated with better diet satisfaction, weight loss and preservation of muscle mass.

As a research professor in the field of nutrition and dietetics, I am convinced that findings from our work, along with other published current evidence, show that the concept that dietary fat is "toxic" is very much outdated and misguided.

Although there is conclusive evidence that one type of fat, trans fat, has no place in a healthy diet, I believe that consumers should start to learn how to balance the other types of fats in the diet.

A Balancing Act

While not all fats are alike, they do share some things in common. They provide energy with approximately nine calories per each gram of fat, they are all broken down during digestion by enzymes in the gastrointestinal tract, and they are well absorbed as fatty acids, or chains of hydrogen and carbon.

But these carbon chains vary in length and their degree of saturation. As a result, dietary fats vary in their effects on the body.

In some instances, the carbon molecules bind to other carbon molecules. In others, they bind to hydrogen molecules. You likely have heard names for these two types of fats—unsaturated and saturated. Unsaturated fats are those in which carbon molecules bind to other carbon molecules. Saturated fats are those in which carbon molecules bind to hydrogen molecules. Within the two broad types of fat, there are differences still.

Among the unsaturated fats, there are those that are mono-unsaturated, or those that have one unsaturated carbon bond, which are found in olive oil and certain kinds of nuts, and there are those that are poly-unsaturated and are found in such foods as walnuts, plant oils, salmon and sardines.

We also have learned that different kinds of saturated fats affect the body in different ways. For example, the 12-carbon lauric acid, 14-carbon myristic acid, 16-carbon palmitic acid and 18-carbon stearic acid are all saturated fats. But stearic acid does not increase LDL-cholesterol levels like the other saturated fats.

While these differences are not new, the understanding of their effects is new, mostly due to findings from more recent studies like my own.

Thus, the amount of total fat in the diet no longer is the sole measure of the health effects of dietary fat. It's also about the type of fatty acid, how long the carbon chain is, and whether the fat is saturated, mono-unsaturated or poly-unsaturated.

The Link to Heart Health

The scientific discourse about the potentially toxic role of dietary fat and cholesterol on human health started in the late 1950s and early 1960s, when scientists discovered how to analyze fats in the lab. They also discovered the link between dietary fat intake, serum levels of total and LDL-cholesterol and risk for cardiovascular diseases in animals.

Because heart disease has been the leading cause of death in the U.S. since the 1930s, the Nutrition Committee of the American Heart Association in 1968 recommended reducing total and saturated fat intake. The emphasis on lowering dietary fat intake was advanced further in 1977 with the publication of the first Dietary Guidelines for Americans by the Senate Select Committee on Nutrition and Human Needs.

Health care professionals in turn shifted their nutrition counseling efforts toward encouraging a low-fat diet. And, the food industry began to develop and produce of a wide-ranging assortment of "low-fat," "reduced-fat," "light" and "fat-free" items.

In the mid-1980s, advice to consume a low-fat diet also became a strategy for weight control. Evidence from the landmark Framingham Heart Study uncovered that obesity increased risk for heart disease, and national data showed that the entire population was getting heavier.

Americans responded with a substantial reduction in the percentage of calories consumed as fat. But humans have a biological preference for the taste of fat. And with fat off the table, millions increased their consumption of dietary carbohydrates to compensate for the loss in flavor and appeal of foods. As a result, there has been a substantial increase in the waistlines of Americans.

An Alternative Approach

Given the mixed scientific evidence on fat, and the diverse roles of dietary fatty acids in health and disease, about four years ago I designed a diet that is moderately high in fat but the types of fat are proportionally balanced, that is, one-third of total fat comes from saturated fats; one-third comes from monounsaturated fats; and one-third comes from polyunsaturated fats.

Based on this balanced moderately-high fat diet approach, my research team developed a 14-day cycle of menus comprised of three meals and two snacks per day that increases intake of foods high in the 18-carbon monounsaturated fat, oleic acid and the 18-carbon and longer chain polyunsaturated fats (more commonly known as omega-3 and omega-6 fatty acids). To do this, we replaced high simple carbohydrate snacks with nuts, we replaced croutons in salads with avocado slices, and we used salad dressings high in safflower oil, canola oil and olive oil.

We have been studying the effects of this balanced moderately high fat diet in adults who are overweight or obese. In a study with 144 women over a period lasting 16 weeks, we found that study participants had significant reductions in abdominal fat and waist circumference; a 6 percent improvement in blood pressure; reduced blood levels of markers of inflammation; and overall a 6 percent reduction in their five- and 10-year cardiovascular risk.

Study participants reported that they found our diet to be highly palatable, satisfying and economically feasible to adhere to. The firm adherence to our balanced moderately high fat diet in the four-month study was reflected by significant changes in participants' plasma fatty acid profiles (the array of saturated and unsaturated fats in the blood) that reflected the fatty acid composition of the diet menus.

In a follow-up study using more in-depth analysis of the lipid response to the balanced moderately high fat diet, we found a difference in response between Caucasian females and African-American females. While the Caucasian females had improvements in serum triglyceride and LDL-cholesterol levels, African-American females had the most significant improvement in HDL-cholesterol levels. These data support the concept that not all people respond to a dietary approach in the same way and there is no one optimal diet for all people.

In another follow-up study of the response to a higher fat diet, we also found that people with a specific genotype had a stronger response, and that response differed by sex, particularly with regard to improvements in HDL-cholesterol being stronger in females versus males.

Thus, I believe the choice of an effective dietary approach must be determined based on an individual's goals and an individual's clinical and metabolic response to the interaction between genes and environment.

There are limited studies on the strategy of balancing the type of dietary fat. While current scientific consensus is that extremes of dietary fat intake, too high or too low, are unhealthy, I believe that a paradigm shift focusing on the types of dietary fats consumed may offer the opportunity to modify our cardiometabolic risk factors without requiring major changes in the amount of fat or calories we consume.

Heidi Silver is an associate professor of medicine at Vanderbilt University.
Disclosure statement: Heidi Silver received funding to study dietary fat from the Atkins Foundation.

Reposted with permission from our media associate The Conversation.

Show Comments ()

EcoWatch Daily Newsletter

Sponsored
Health
PxHere

This Common Preservative in Processed Food May Be Making You Tired

By Brian Mastroianni

Is it hard to motivate yourself to get off the couch and go exercise?

Keep reading... Show less
Popular
MarioGuti / iStock / Getty Images

EVs 101: Your Guide to Electric Vehicles

By Patrick Rogers

If you have ever considered making the switch to an environmentally friendly electric vehicle, don't drag your feet. Though EV prices are falling, and states are unveiling more and more public charging stations and plug-in-ready parking spots, the federal government is doing everything it can to slam the brakes on our progress away from gas-burning internal combustion engines. President Trump, likely pressured by his allies in the fossil fuel industry, has threatened to end the federal tax credits that have already helped put hundreds of thousands of EVs on the road—a move bound to harm not only our environment but our economy, too. After all, the manufacturing and sale of EVs, hybrids, and plug-in hybrids supported 197,000 jobs in 2017, according to the most recent U.S. Energy and Employment Report.

Keep reading... Show less
Animals
An adult bush dog, part of a captive breeding program. Hudson Garcia

A Rescue Dog Is Now Helping to Save Other (Much Wilder) Dogs

By Jason Bittel

Formidable predators stalk the forests between Panama and northern Argentina. They are sometimes heard but never seen. They are small but feisty and have even been documented trying to take down a tapir, which can top out at nearly 400 pounds. Chupacabras? No.

Keep reading... Show less
Health
RoNeDya / iStock / Getty Images

What Is Mead, and Is It Good for You?

By Ansley Hill, RD, LD

Mead is a fermented beverage traditionally made from honey, water and a yeast or bacterial culture.

Keep reading... Show less
Sponsored
Climate
U.S. Army member helps clear debris from Tyndall Air Force Base following Hurricane Michael. U.S. Army

Pentagon: Climate Change Is Real and a 'National Security Issue'

The Pentagon released a Congressionally mandated report (pdf) that warns flooding, drought and wildfires and other effects of climate change puts U.S. military bases at risk.

The 22-page analysis states plainly: "The effects of a changing climate are a national security issue with potential impacts to Department of Defense (DoD or the Department) missions, operational plans, and installations."

Keep reading... Show less
Popular
Protesters interrupt the confirmation hearing for Andrew Wheeler on Capitol Hill Jan. 16 in Washington, DC. Chip Somodevilla / Getty Images

5 People Calling Out EPA Acting Head Wheeler for Putting Polluters First

This week, people across the country are joining environmental leaders to speak out against the nomination of former coal lobbyist Andrew Wheeler to lead the the U.S. Environmental Protection Agency (EPA). As Scott Pruitt's hand-picked successor, Wheeler has continued to put polluters over people, most recently by using the last of his agency's funding before it expired in the government shutdown to announce plans to allow power plants to spew toxic mercury and other hazardous pollution into the air.

Keep reading... Show less
Sponsored
Popular
Great white shark. Elias Levy / Flickr / CC BY 2.0

Marine Biologists Raise Flags About Viral Great White Shark Encounter

By now you might have seen Ocean Ramsey's rare and jaw-dropping encounter with a great white shark in waters near Oahu, Hawaii.

Ramsey, a marine biologist, said on the TODAY Show that it was "absolutely breathtaking and heart-melting" to be approached by the massive marine mammal.

Keep reading... Show less
A tree found severed in half in an act of vandalism in Joshua Tree National Park. Gina Ferazzi / Los AngelesTimes / Getty Images

Wall Before Country Takes Mounting Toll on Americans Everywhere

By Rhea Suh

One month on, the longest and most senseless U.S. government shutdown in history is taking a grave and growing toll on the environment and public health.

Food inspectors have been idled or are working without pay, increasing the risk we'll get sick from eating produce, meat and poultry that isn't properly checked. National parks and public wilderness lands are overrun by vandals, overtaken by off-road joyriders, and overflowing with trash. Federal testing of air and water quality, as well as monitoring of pollution levels from factories, incinerators and other sources, is on hold or sharply curtailed. Citizen input on critical environmental issues is being hindered. Vital research and data collection are being sidelined.

Keep reading... Show less
Sponsored

mail-copy

The best of EcoWatch, right in your inbox. Sign up for our email newsletter!