A small, randomized feeding trial suggests that plant-forward diets may support strength and metabolic markers in older adults, regardless of whether protein comes from animal or plant sources.
Before reviewing the findings, it is important to note that the research was funded by the National Pork Board. The study authors reported no personal conflicts of interest, and the research was peer-reviewed.
The study, published in Current Developments in Nutrition, followed 36 adults aged 65 and older in an 18-week randomized controlled crossover feeding trial. Each participant completed two diet phases, consuming one dietary pattern for 18 weeks before switching to the other.
Both diets were designed to be plant-forward and aligned with U.S. dietary guidance, emphasizing vegetables, fruits, whole grains and minimally processed foods. Calories, macronutrients and overall diet quality were closely matched. The primary difference between the two patterns was protein source at lunch and dinner. One diet included minimally processed lean pork, such as roasted pork loin, while the other emphasized lentils and other pulses.
The study did not include a prescribed exercise program, allowing researchers to examine whether diet quality and protein patterns alone influenced markers related to aging.
Researchers assessed body weight, body composition, fasting insulin and functional measures associated with independence in older adults, including grip strength and chair-rise performance. Blood-based biomarkers related to nutrition and neurotransmitter pathways were also analyzed. The study did not measure clinical cognitive outcomes.
Across both diet phases, participants lost weight while maintaining grip strength and chair-rise performance. Fasting insulin levels decreased during both dietary patterns. When compared with baseline, researchers observed a significant improvement in an estimate of insulin sensitivity following the pork-containing phase. When comparing the end of each diet phase, HDL cholesterol levels were higher after the pork phase than after the lentil phase.
The researchers also observed shifts in several neuroactive metabolites and amino acids following both dietary patterns, which they characterized as mostly favorable. These biomarkers are considered indirect indicators and do not demonstrate changes in cognitive performance.
The findings suggest that plant-forward eating patterns can support markers of physical function and metabolic health in older adults over the short term. However, the authors note several limitations, including the small sample size, the relatively short duration of the intervention and the use of biomarkers rather than clinical cognitive measures.
The results do not establish that pork is necessary for healthy aging, nor do they overturn broader evidence linking certain red meats to health risks. Instead, the study highlights that different protein sources may fit within a high-quality, plant-forward dietary pattern, depending on individual preferences and dietary habits.