Effects of the EatWelLog App on Enhancing Daily Diet Management for Community-dwelling Older Adults With Sarcopenic Obesity: A Pilot Randomized Controlled Trial

Sarcopenic obesity (SO), characterized by concurrent reduced muscle mass and excess body fat, affects 11% older adults worldwide, rising to 23% among those over 751. Older adults with reduced muscle mass are 1.95-2.62 times prone to obesity than those with normal muscle mass. This is due to shared etiological factors between sarcopenia and obesity such as sedentary habits and aging-related biological shifts, including decreased anabolic hormones, increased insulin resistance, and escalated oxidative stress. The combination of sarcopenia and obesity has a compounding negative impact on health, raising the likelihood of knee and hip osteoarthritis, which leads to reduced physical capabilities, as well as increasing the risk of cardio-metabolic diseases, institutionalized, and death, exceeding the risks of sarcopenia or obesity alone.

Addressing SO effectively to promote muscle mass gains while reducing fat mass remains a significant challenge, necessitating urgent and effective intervention strategies. Currently, exercise and nutrition interventions, are the most commonly recommended interventions.

Exercise and Nutrition Interventions for SO A recent systematic review of 11 trials with 440 SO participants showed that resistance training twice weekly for 20 minutes over a minimum of 8 weeks effectively enhances body composition, muscle strength, and gait speed. Furthermore, evidence suggested that combining aerobic and resistance training with increased protein intake is more effective in reducing body fat than resistance training alone but had no effects on muscle mass and strength. Another systematic review of eight trials with 605 SO participants found that resistance training alone could increase muscle strength. To also improve physical functions (i.e., gait speed and grip strength), exercise combining aerobic and resistance training with dietary supplements seems to have more promising results. The findings in a recent umbrella review of meta-analyses concluded that exercise interventions (either resistance training or combined resistance and aerobic exercise) are beneficial for body composition and physical performance in older adults with SO. However, the added value of exercise with nutrition interventions (either protein supplement and dietary modifications) produces inconsistent results.

Adequate protein intake is vital for muscle building, and calorie restriction is effective at reducing fat mass. Thus, nutrition is a critical factor in the onset and progression of SO, although the evidence for nutrition interventions in reserving SO demonstrated inconsistent effects, especially regarding muscle mass and strength. When implementing a weight loss diet for individuals with SO, it is important to balance fat reduction with muscle mass preservation by ensure adequate protein intake to prevent exacerbating muscle loss. Evidence suggests that the source of protein is crucial for muscle retention, specifically for animal-based proteins, which are high in leucine, may be more effective in preserving muscle mass during weight loss and in maintaining physical function. While nutritional supplements are commonly used to increase protein intake, their effects on SO remain inconsistent and may cause side effects such as digestive issues, interact with certain medications, dehydration, liver and renal damage, bloating, and calcium loss. The investigators advocates for an unhealthy diet incorporating a full spectrum of nutrients from whole foods, in line with the Dietary Guidelines for Americans, 2020-2025, as the preferred approach over supplements for those with sarcopenic obesity. Modifying daily dietary habits of individuals with SO may provide more sustainable benefits than merely adding supplements to their diet.

A recent systematic review examining nutrition interventions in managing sarcopenic obesity analysed nine studies but only two assessed the impact of dietary modifications on protein intake among older adults with SO. The first randomized controlled trial (RCT) assessed the impact of a low-calorie diet with normal (0.8 g/kg body weight/day) versus high protein intake (1.2 g/kg body weight/day) over three months in 104 older women with SO. The study found muscle mass decreased in the normal protein group concurrent with fat loss, while the high protein group saw muscle mass preservation. The second pilot RCT involving 18 women compared a low-calorie diet with placebo to one with high protein (1.2-1.4 g/kg body weight/day) over four months. Significant muscle strength gains were noted in the high protein group, though changes in muscle mass were not significantly different between the two groups. While the findings in these two trials provided preliminary evidence that hypocaloric diet and high protein intake may be necessary for managing SO, particularly for preserving mass muscle and strength. These studies, however, had limitations such as broad inclusion criteria for sarcopenic obesity, lacking a standardized diagnostic protocol, insufficient data on dietary adherence, and opaque details regarding randomization and intervention specifics. More rigorous research is needed to investigate the impact of diet modification on sarcopenic obesity.