Plant-based protein for older adults with obesity

The global syndemic of obesity, undernutrition and climate change - three interconnected challenges - threatens both human and planetary health. This review focuses on one critical intersection: older populations living with overweight and obesity in the context of sustainable nutrition. Obesity and sarcopenia, particularly the co-occurrence called sarcopenic obesity, are often overlooked until the onset or exacerbation of other diseases necessitates secondary care. Preventing sarcopenic obesity requires reducing excess fat mass while preserving muscle mass and function. This involves lowering total energy intake while ensuring adequate protein intake in terms of quantity, quality and distribution, combined with physical activity, particularly resistance exercise. Short-term studies show that both the source and dose of dietary protein significantly influence muscle protein synthesis rates. Longer-term studies examining the impact of plant-based diets on muscle health in older adults with or without overweight or obesity remain limited. Animal protein have shown a modest advantage over most plant-based protein in supporting muscle mass. Qualitative studies suggest that emphasising both the health benefits and palatability of plant-based protein sources is key to promoting dietary changes in older adults. In older adults with obesity, it is challenging to combine energy restriction with higher protein intake, especially when protein sources are plant-based. To prevent and treat sarcopenic obesity in older adults and support planetary health, a shift toward more plant-based protein sources is required, while ensuring sufficient protein quantity and quality to preserve muscle health during weight loss.