YOUR BODY'S NO.1 ENEMY

Think sugar is bad? Experts say vegetable oil — in tons of tasty snacks — is worse

N the middle of the 20th century, concerned by the growing heart-attack epidemic, Americans ditched butter and other saturated fats in favor of vegetable oils.

According to Dr. Catherine Shanahan, author of the new book “Deep Nutrition: Why Your Genes Need Traditional Food” (Flatiron Books, out now), that was a fatal mistake.

Shanahan — a family physician based in Denver with a degree in biochemistry and genetics — has built a career around bucking nutritional norms. Unlike many doctors and dietitians who suggest diets packed with fruits and vegetables, Shanahan recommends an eating plan based on animal fats and proteins, along with traditional healthy foods such as vegetables and nuts. She began her career practicing medicine and studying traditional diets in Hawaii, and gained a fan in Kobe Bryant. She overhauled his diet, taking out vegetable oils and sugar and adding in foods such as bone broth, and went on to became the director of the Los Angeles Lakers’ nutrition program, a position she still holds. With the release of “Deep Nutrition,” she’s made it her mission to get Americans to ditch vegetable oils — or, in her words, “your brain’s worst enemy.” To understand the problem with the substances — which include canola, palm, corn, soy, sunflower, safflower, cottonseed, rice bran and grapeseed oils (but not olive, coconut, avocado or peanut oils) — Shanahan says, you have to understand why we began eating vegetable oils

Both Girl Scout cookies and Nutella contain palm oil, a type of vegetable oil found to be potentially carcinogenic. But, Nutella claims its oil is processed to be less harmful.

in the first place. “In the 1950s, we were told we couldn’t have saturated fats,” she says. “We stopped eating butter and natural fats, but still craved fatty foods, so we turned to vegetable oil[s]. And then restaurants started using them because they’re dirt cheap.”

While unsaturated vegetable oils seemed healthy at first, recent research has shown that they may be more destructive than the fats they replaced. One re-evaluation of a heart study from the 1970s, published in April in the British Medical Journal, questioned the original finding that consuming vegetable oils instead of saturated fats can lower the risk of heart disease and death. It found that consuming too much vegetable oil may actually increase the risk of heart disease.

Researchers believe that this may be due to what happens when vegetable oils are processed or heated during cooking.

“The way the oils have been treated strips away the anti-oxidants,” says Shanahan. As a result, the balance between disease-fighting antioxidants and free radicals is tipped in favor of free radicals, which have been shown to promote disease. (Shanahan’s claims have a foundation in previous studies, but most of her specific ideas have not been scientifically tested.)

While Shanahan says that vegetable oils can wreak havoc on all areas of the body, she’s particularly concerned about the brain. Regularly consuming vegetable oils can lead to lethargy and trouble concentrating in the short term, she believes, and, in her view, might trigger brain conditions, such as Alzheimer’s or dementia.

“The No.1 symptom someone would feel is migraines,” she says.

Maria Elena Rodriguez, a registered dietitian and diabetes educator at Mount Sinai Hospital, has a more moderate view. “On a scale of oils, vegetable oils land somewhere in the middle” in terms of how bad they are, she says.

Still, Rodriguez says, vegetable oils shouldn’t be the basis of anyone’s diet. “When we’re talking about heart health, diets that are high in veg- etable oils can lead to plaque buildup and heart disease.” They can also cause inflammation.

But she’s not a fan of replacing vegetable oils with saturated fats from butter or coconut oil. “Saturated fat is shown to have a higher risk of plaque, heart disease, diabetes and inflammation,” Rodriguez says — claims that Shanahan calls outdated and based on faulty science.

New research appears to back up Shanahan. The European Food Safety Authority issued a report in May warning against high levels of contaminants in palm oil, an inexpensive vegetable oil used in Nutella, margarine, most Girl Scout Cookies and other treats. The report cautioned against potential gerotoxins and carcinogens that are created when the oil is heated over roughly 400 degrees Fahrenheit during refining. The EFSA announced last week that it will reexamine the warning.

A rep for Ferrero, the company that makes Nutella, tells The Post that the palm oil used in the chocolate spread is refined at lower heat, and therefore contains fewer contaminants. The Girl Scouts of the United States of America say they are aware of potential risks and are working closely with their bakers to determine if there is any cause for concern in light of the new studies. “Providing safe products is always our top priority,” the organization said in a statement to The Post.

The FDA, typically less cautious than the EFSA on such matters, has yet to weigh in on palm oil.

Research is raising other red flags. In 2015, scientists at England’s De Montfort University cautioned that heating sunflower and corn oils produced much higher levels of aldehydes — compounds that may cause heart disease and cancer — than fats such as olive oil and goose fat. Other studies have also raised concerns over potential disease-causing properties of vegetable oils.

At the same time, there’s been a resurgence in appreciation for old-school fat sources, from butter to lard.

Shanahan says: “Why not go with a healthier, tastier fat?”