Effects of the EatWelLog App on Enhancing Diet Management for Older Adults With Sarcopenic Obesity

Background Sarcopenic obesity (SO), characterized by reduced muscle mass alongside excess body fat, affects 9.95% of Chinese1 and 11% worldwide2, with prevalence exceeding 23% among those 75+1,2.. SO poses greater risks of osteoarthritis, cardio-metabolic diseases, institutionalization, and mortality, than sarcopenia or obesity alone3. Healthcare costs for obese individuals are triple those of individuals with normal BMI (US$16,348 vs US$5,814)4. Sarcopenia alone accounted for an estimated US$18.5 billion in 2000 (1.5% of total healthcare expenditures), with a 10% reduction in prevalence potentially saving US$1.1 billion5. SO's economic burden likely amplifies these costs, highlighting the need for targeted interventions.

Mobile health (m-Health) applications offer a convenient, personalized, and cost-effective alternative to traditional care. Features such as self-monitoring, automated feedback, and interactive messaging enhance treatment adherence, foster peer support, and overcome the barriers of in-person consultations6,7. While evidence shows apps significantly improve nutritional behaviors in chronic disease management, maintaining long-term user engagement remains a challenge8.

Currently, a critical research gap exists: no nutritional app specifically targets SO to support mandatory low-calorie, high-protein diets. The proposed EatWelLog App aims to bridge this gap. By encouraging healthy dietary habits, evaluating long-term usage data, and linking engagement patterns to health outcomes, this digital intervention has the potential to revolutionize SO management and deliver sustainable, cost-effective health outcomes.

Study Objectives \& Hypotheses Objectives: The study aims to evaluate the effects of an mHealth-based intervention using the EatWelLog App, developed by our research team, to empower people's self-management of a healthy diet and thereby improve their sarcopenic obesity status. The expected benefits include reducing body fat and improving muscle health.

Hypotheses: Compared with the control group receiving the same supervised nutrition and exercise programme without the App, the mHealth group using the App during and after the supervised programme will demonstrate sustained improvements in sarcopenic obesity status.

Study Design \& Methodology Study Design: The study will adopt a two-arm, assessor-blinded, parallel-group randomized controlled trial design.

• An m-Health group receiving an 8-week supervised nutrition and exercise programme, and training to incorporate the App for daily dietary management,
• A control group receiving the identical 8-week supervised programme without the App.

Participants:

Sample size: 212 (106 per group) community-dwelling older people with SO

Inclusion criteria:

1. Age 50+;
2. Having SO according to the Asian Working Group for Sarcopenia (AWGS)9 and the WHO's obesity criteria for Asians9:
3. Early-stage sarcopenia refers to the fulfillment both of the following criteria:
4. For participants aged 50-64: low handgrip strength < 34 kg for men and < 20 kg for women, low muscle quality as reflected by low appendicular skeletal muscle mass (ASM) /height squared < 7.6 kg/m2 for men and <5.7 kg/m2 for women. For participants aged 65 or above: handgrip strength <28kg (men) and <18 kg (women); appendicular skeletal muscle mass (ASM)/ height2 <7 kg/m2 (men) and <5.7 kg/m2 (women).
5. Obesity is indicated by BMI ≥25 kg/m2, waist circumference ≥90 cm (men) and ≥80 cm (women)9, or body fat >30%10. fulfil either one criterion to indicate the status of obesity.
6. Smartphone owners with internet access
7. Chinese (Cantonese) literacy and no significant sensory impairments

Exclusion criteria: Individuals who:

1. have diseases that impact digestion or food consumption, including severe cardiac/ pulmonary/ renal diseases, diabetes, cancer, or autoimmune disorders.
2. are on medications that affect eating habits/ digestion/ metabolism, such as weight loss drugs.
3. have alcohol use disorder as defined by the Manual of Mental Disorder (DSM-5), which may hinder dietary behaviour changes.
4. have medical implants like pacemakers that could be disrupted by the low-level electrical currents of the bioelectric impedance analysis (BIA).
5. have a Functional Ambulatory Classification (FAC)11 score of <7, indicating impaired mobility to participate in exercise training

Focus group: Thirty m-Health participants will be divided into 5-8 focus group (4-6 participants per group) for interviewed by a trained research assistant (RA) to understand their App user experiences.

Interventions:

Both groups will separately receive an 8-week supervised programme including a personalized dietary modification programme and group-based exercise. The research team's involvement will conclude after the programme for both groups. However, the m-Health group will continue using the App for daily dietary self-management during and after the programme.

The 8-week Intervention components for both the m-Health and control groups:

• Dietary modification programme: aims to improve the participants' self-efficacy in adopting our previously validated diet regimen*12,13. It includes eight personalized, one-hour, face-to-face sessions.
• *Dietary Regimen: a moderate hypocaloric diet reduces daily energy intake by 12% for steady weight loss while preserving muscle mass9. To address the reduced anabolic response in older people, a protein intake of 1.5 g/kg of body weight per day is recommended, with leucine-rich animal proteins prioritized to enhance muscle development9.
• Exercise Training: involves weekly one-hour group sessions for 8 weeks, with groups of approximately ten. The training combines resistance and aerobic exercises to increase muscle mass and strength while reducing fat in SO individuals7. Each session includes a 10-minute warm-up and cool-down period, 20 minutes of resistance training, and 20 minutes of brisk walking, supervised by an instructor for practice and feedback. Participants will receive a YouTube link and pamphlet detailing exercises to follow 30 minutes daily, five times a week, during and after the programme.

Intervention components for the m-Health group:

• The EatWelLog App: designed for older people with SO, incorporates Klasnja and Pratt's m-health development framework to facilitate health behavioural change7 by integrating BCT14 to support ongoing adherence to dietary regimens.

The control condition:

• After the 8-week programme (identical to the mHealth group but conducted separately), the control group will be encouraged to follow dietary and exercise guidelines independently, with no further formal interactions or training. To ensure they are not deprived of the App's benefits, they will receive a training session on using the App and full access to it after completing the 12-month follow up.