Reviewed by Dietitian Madeline Peck, RDN, CDN
Credit: EatingWell design
Key Points
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Older adults are at a higher risk for falls due to declines in muscle mass and strength.
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Researchers found that a daily serving of peanut butter may improve lower-body power.
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A healthful diet and regular strength exercise is essential for healthy aging.
While getting older is a privilege, some of the changes that come with it? Not so much. Muscle mass and strength naturally begin to decline as early as your 30s—and the process tends to accelerate after 50. Meanwhile, social media is brimming with “longevity hacks” promising to preserve your body composition and keep you strong for decades to come. But what picture-perfect social media posts often leave out is a less glamorous reality of healthy aging: maintaining muscle power and muscle strength to prevent falls. This matters because the risk of falls increases with age–about one in four American adults age 65 and older fall each year.
Traditionally, a nutritious diet and regular strength training have been considered key strategies for reducing age-related declines, including fall risk. However, new research suggests that a simple daily habit—incorporating peanut butter into your diet—may also play a role in maintaining muscle strength and power.
To find out whether this pantry staple could make a difference in healthy aging, researchers in Melbourne, Australia set out to examine what would happen if older adults added peanut butter to their daily eating pattern. Rather than focusing on extreme diets or complicated exercise protocols, the intervention was surprisingly straightforward: consume a consistent amount of peanut butter each day and monitor changes in physical function over time.
In fact, an extra spoonful per day of peanut butter may not be as random as it sounds. Peanut butter provides plant-based protein, healthy fats and calories—nutrients that can be especially important for older adults working to maintain muscle and overall strength. So researchers set out to answer a simple question: Could this small dietary change meaningfully support physical composition and healthy aging?
How Was the Study Conducted?
Researchers at Deakin University’s Institute of Physical Activity and Nutrition (IPAN) in Melbourne, Australia conducted a six-month, single-blind, randomized controlled trial to get clear answers. They recruited 108 community-dwelling adults, ages 65 and older, who were considered at risk for falls.
First, participants were randomly assigned to one of two groups:
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The Peanut Butter Group: This group received 43 grams (about 1.5 servings) of peanut butter daily for six months.
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The Control Group: This group was instructed to continue their usual eating habits and was asked to avoid nuts during the six-month study period.
Both groups were directed to maintain their usual levels of physical activity and exercise. In addition, all participants completed questionnaires collecting information about demographics and health at baseline.
To evaluate whether peanut butter made a difference, researchers assessed physical function at baseline and again after six months by measuring gait (walking) speed, lower-body strength and power—assessed using the Five Times Sit to Stand (5STS) Test and the 30-second sit-to-stand (STS) performance—balance and mobility, handgrip and knee extension strength and body composition using dual-energy X-ray absorptiometry (DXA) scans. They also assessed dietary intake, overall diet quality, physical activity levels and self-reported late-life function and disability.
Throughout the six-month study, participants had three- and six-month check-in visits with researchers where individuals in the peanut butter group were instructed to return any unopened peanut butter containers to monitor adherence.
What Did the Study Find?
The results showed modest but meaningful differences between the two groups. While gait speed did not significantly change, participants who snacked on peanut butter daily experienced improvements in their lower-body power compared to the control group.
Specifically, the peanut butter group reduced the time it took to complete the 5STS test and demonstrated increases in absolute sit-to-stand muscle power. These improvements suggest better lower-body function, which plays an important role in everyday activities like rising from a chair or climbing stairs. It’s worth noting that both groups improved their performance on the 30-second sit-to-stand test over time, which may reflect a learning effect or increase in familiarity with the assessment. Additionally, adherence rates averaged 86%, meaning this intervention was feasible for most older adults.
Interestingly, researchers also observed an improvement in overall diet quality among those in the peanut butter group. Because the daily peanut butter serving added approximately 250 calories, 20 grams of fat and 10 grams of protein, total energy intake amongst the peanut butter group increased significantly–but did not lead to weight gain. This aligns with previous research suggesting that nut consumption can support satiety and diet quality without contributing to unintended weight gain.
While participants in the peanut butter group did experience some beneficial results, it’s worth noting the limitations of this study. Participants were generally well-nourished, had average protein intake exceeding current recommendations and demonstrated relatively high baseline physical function. In populations like this, it can be challenging to detect meaningful changes in physical outcomes, as improvements are more likely to be observed in individuals who are malnourished, have inadequate protein intake or have functional impairments.
How Does This Apply to Real Life?
If you want to support physical function as you age, this study suggests that eating peanut butter daily may play a small but potentially meaningful role in maintaining lower-body power. Participants consumed about 1.5 servings (43 grams) of peanut butter per day for six months, and adherence was high—around 86%—suggesting that this could be a realistic and sustainable habit for many older adults.
Notably, other research suggests that maintaining lower-body power–not just maximal strength–is especially important for survival and independence in older adults, making the findings from this study important. Low muscle power has been linked to mobility limitations and a higher likelihood of walking difficulties, meaning that even small improvements in muscle power—like those seen from a daily spoonful of peanut butter—could help preserve independence and reduce fall risk as we age.
That said, a daily spoonful of peanut butter isn’t a magic solution for living a long, happy life. While it may help support lower-body power, it didn’t significantly change walking speed or overall muscle mass over six months. Maintaining strength, mobility and independence as we age still requires an overall balanced diet with adequate protein, paired with regular strength-building activities.
Our Expert Take
A recent six-month randomized controlled trial conducted at Deakin University’s IPAN in Melbourne, Australia, examined whether eating peanut butter daily could improve physical function in older adults. The results? While participants who added peanut butter to their diets saw improvements in lower-body power, there were no significant changes in walking speed or overall muscle mass. The findings suggest that while peanut butter can be part of a nutrient-dense eating pattern, maintaining strength and function as you age likely requires a combination of an overall healthful diet paired with regular strength-building movement. In other words, peanut butter alone won’t solve all your concerns about aging well–but it can be one part of a balanced approach.
Read the original article on EatingWell