NutritionTop 25 · #2
How Much Protein Do You Really Need After 50?
The standard protein recommendation of 0.8 g/kg/day was never designed for adults over 50. A 2025 expert consensus says you likely need 25–50% more.
March 2026 · 7 min read
Behavior ChangeTop 25 · #4
Why Exercising With a Friend Works Better Than Willpower
A rigorous clinical trial tested individual vs. social strategies for getting older adults to move more. The results surprised the researchers.
March 2026 · 6 min read
Based on:
McMahon et al. (2024)
Effect of intrapersonal and interpersonal behavior change strategies on physical activity among older adults
JAMA Network Open
2x2 Factorial RCT, N=309Most behavior change programs focus on the individual: set goals, track your steps, plan your workouts. It's the foundation of nearly every fitness app and wellness program on the market. A 2024 clinical trial published in JAMA Network Open tested whether that approach actually works for adults over 70 — and the answer was surprising.
How the study worked
McMahon et al. designed a 2x2 factorial randomized controlled trial with 309 adults aged 70 and older (mean age 77.3, 63% female). All participants were insufficiently active at baseline. They were randomly assigned to one of four groups: intrapersonal strategies only (goal setting, self-monitoring, action planning), interpersonal strategies only (partnered activities, group walks, social accountability check-ins), both strategies combined, or a health education control group.
Crucially, the study used accelerometer-measured physical activity rather than self-report. When people report their own activity levels, they tend to overestimate. Accelerometers don't lie.
The result that mattered
The intrapersonal strategies — goal setting, self-monitoring, action planning — showed no significant independent effect on physical activity. The tools that form the backbone of most wellness programs simply didn't move the needle for this population when used alone.
The interpersonal strategies told a different story. Partnered activities and social accountability produced a significant increase of 27.1 minutes per day of total activity at one week (P<.001), and this effect was sustained through 12 months of follow-up. Light physical activity increased significantly with interpersonal strategies at all measured time points.
Social connection was the active ingredient
Perhaps the most telling finding: combining both approaches did not produce additive effects. Adding goal setting and self-monitoring on top of social strategies didn't make them work better. The social connection was the active ingredient. Everything else was noise.
This challenges a deeply held assumption in the wellness industry — that if we just give people better tools for self-management, they'll change their behavior. For adults over 70, at least, the evidence points in a different direction entirely.
What this means in practice
The practical takeaway is simple: if you want to move more, find someone to move with. The data suggests that for adults over 70, social accountability matters more than self-tracking. A walking buddy may be more effective than a fitness app. A group exercise class may do more for your long-term activity levels than the most carefully designed personal goal-setting worksheet.
This is an educational summary of peer-reviewed research. It is not medical advice. Always consult your healthcare provider before making changes to your health routine.
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