New Study Says an Apple a Day Might Keep You Slim

Apple Sandwiches

Photo and Recipe by Perry Santanachote

If the old adage, “an apple a day keeps the doctor away,” wasn’t enough to get you pumped about the crunchy fall fruit, apples are now getting props for helping people fight fat as well. New research published this week in the journal Food Chemistry reveals that a compound in apples could actually help prevent obesity-related inflammation, too.

“Apples in general are a package of bioactive compounds including polyphenolics and fiber, which have been shown in several studies to exert health benefits [and] prevent or delay the progress of diseases related to obesity,” says study author Giuliana Noratto, an assistant professor of food science at Washington State University.

RELATED: Mini Peanut Butter and Apple Sandwich Recipe

These compounds make it easy to argue that apples are a bona fide superfood: Polyphenols are an antioxidant often found in plants, and a polyphenol-rich diet has been shown to help protect against cancer, cardiovascular disease and diabetes. Additionally, fiber, a non-digestible carbohydrate, helps people stay full and keeps blood sugar under control, while also aiding digestion. 

The Healthiest Apple, Revealed

If you’ve spent any time in a grocery store, you know apples come in a variety of shapes, size, colors and flavors. The researchers set out to compare and contrast the beneficial compounds in several beloved cultivars including Braeburn, Fuji, Gala, Granny Smith, Golden Delicious, McIntosh and Red Delicious. They found that one apple seemed to rise above the rest: the tart, green Granny Smith.

“We identified Granny Smith for its enhanced content of polyphenolics and fiber, [and] low content of available carbohydrates, which makes it a novel apple to combat obesity,” Noratto says.

Once identified, the scientists ran tests to discover if the compounds in Granny Smith apples could potentially help change the proportions of fecal bacteria in obese mice. According to Noratto, obese people often suffer from an imbalance of bacteria in the colon, leading to low-grade, chronic systemic inflammation and metabolic disorders.

“It has been demonstrated that [inflammation] is the cause of metabolic disorders that lead to increased fat synthesis and [fat] storage in the adipose tissue, liver and muscle,” Noratto says.

The researchers believe that by restoring a balance of bacteria in the gut, the inflammation at the root of these metabolic disorders can be resolved. Supporting this theory, the team found that compounds in Granny Smith apples actually changed the balance of fecal bacteria in obese mice to be more similar to the proportions found in lean mice.

In other words, adding Granny Smiths to your grocery list might not be a bad idea.

One tip: While baked apples are tasty, raw apples may be most beneficial to your health. “The cooking process degrades polyphenolics,” Noratto says. 

Have we got you craving the crunch of an apple? Check out these 10 Amazing Apple Recipes for Fall