One avocado daily makes a significant impact, trial reveals

By Lisa Marie Basile | Fact-checked by Davi Sherman
Published April 16, 2024

Key Takeaways

  • A randomized, controlled trial split participants with obesity into two groups to assess avocados’ impact on diet quality.

  • The first group added one avocado per day to their diet while the second group did not. At 26 weeks, the first group saw improvements in diet quality (measured by the Healthy Eating Index 2015) compared to the second group.

  • The study’s authors also found that avocados caused neither weight gain nor weight loss.

A recent multicenter, randomized, controlled trial found that eating one entire avocado every day is associated with improved diet quality, according to findings published in Current Developments in Nutrition.[] 

The trial aimed to examine how food-based interventions impact changes in the Healthy Eating Index (HEI)-2015, a measure of diet quality used to assess how well certain foods align with key recommendations and dietary patterns published in the Dietary Guidelines for Americans (Dietary Guidelines). Additionally, the trial focused on associations between HEI-2015 change and intervention effects on cardiometabolic risk.[] 

Originally, the researchers examined the impact of daily avocado intake on abdominal obesity, but their focus changed to the avocado’s impact on overall diet quality.[] 

Over 26 weeks, 1,008 participants aged 25 years or older with abdominal obesity (defined by women with waists measuring 35 or more inches and men with waists measuring 40 or more inches) were divided into two groups: One group (the avocado-supplemented diet group) ate one avocado per day, while the other group (the habitual diet group) maintained their typical diet. The former group did not change their diet in any other way, while the latter group was required to limit avocado intake to two or fewer per month.

The research team assessed the results utilizing the HEI-2015 from one 24-hour recall conducted at four different time points. 

Researchers found that the avocado-supplemented diet group experienced increases in diet quality (per the HEI-2015) at 26 weeks compared to the habitual diet group. Improvements occurred in a few key areas, including total vegetable intake, fatty acid ratio, sodium, refined grains, and added sugars. There were no notable differences across race, ethnicity, study site, body mass index, or age.  

“We saw improvements in vegetable intake and overall diet quality, which we know is associated with lower risk of many diet-related chronic diseases in heart disease, type 2 diabetes, and cancer,” Kristina Petersen, PhD, study author and Associate Professor and Professor in Charge at Penn State University’s Graduate Program in Nutritional Sciences, tells MDLinx.

However, there were gender differences: “In the avocado-supplemented diet compared with the habitual diet group, the HEI-2015 increased in females (6.50 points; 95% CI: 4.39, 8.62) but not in males (0.02 points; 95% CI: −3.44, 3.48),” the authors write. They note, however, that “this observation was attenuated…after adjustment for baseline total HEI-2015 score, suggesting the effect was driven by differences in baseline HEI-2015 scores.”

The team also found that the average HEI-2015 change was not associated with intervention-related changes in cardiometabolic disease risk factors. “The findings demonstrated that the habitual dietary incorporation of 1 avocado per day did not reduce visceral adipose tissue volume and had minimal effect on risk factors associated with cardiometabolic disorders,” the authors note.

That said, the authors believe that “there is a need to examine how food-based interventions alter diet quality and the relationship with risk factors for chronic diet-related diseases.” 

“Avocados are a generally well-liked vegetable. However, often people avoid them because of the high fat content and fears of weight gain. In our study, we saw no weight change when participants ate one avocado per day for six months,” Dr. Petersen says. “Correcting the misperception about avocados promoting weight gain may be needed for some patients to incorporate them into their diet.”

Jen Scheinman, MS, RDN, CDN, the owner of Next Jen Health, agrees. “Avocados are loaded with monounsaturated fats, which studies show are great for heart health. These fats help lower LDL (bad) cholesterol, which can reduce the risk of heart disease and stroke,” she says. “Plus, avocados are [rich in fiber], which most Americans lack in their diet. Fiber has so many benefits. It’s great for heart health, blood sugar stabilization, gut health, and weight management.”

Although the authors found that one avocado per day had no impact on weight gain or loss, Autumn Beam MS, ACN, CNS, LDN, Chief Nutrition Officer at Hope Wellness in Los Angeles, CA, says that people shouldn’t go overboard with the food: “There are some downsides to be mindful of: Avocados are calorie-dense due to the fat content, and you can easily move into eating too many calories for the day if you aren't paying attention. Those who do not process fats well or who are histamine-sensitive may also have trouble consuming avocados.”

Petersen also tells MDLinx that she and her team didn’t tell the participants how to eat the avocado each day,  and that they incorporated it in many different ways. For those who want to integrate the popular food but aren’t sure how to, Scheinman suggests making guacamole to use as a dip, as a spread for toast, or on top of eggs. She says that it makes a great replacement for mayonnaise as well. “Since avocados can [become overripe] quickly, I love freezing cubes of avocado and keeping them in the freezer to toss in smoothies. They help make the smoothie really creamy without adding any off flavors,” she adds.

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