Author(s): ZHANG, H., LIAO, Q., CHENG, Y., CHEN, J., QU, Y., WANG, Y., SUN, F., ZHENG, C., Institution: THE EDUCATION UNIVERSITY OF HONG KONG, Country: CHINA, Abstract-ID: 1211

INTRODUCTION:
The growing older adult population faces elevated risks of abdominal obesity, a condition linked to metabolic disease. The 5:2 intermittent fasting diet offers comparable efficacy to daily caloric restriction with potentially better adherence. Furthermore, multicomponent structured exercise (MSE) promotes fat loss while countering sarcopenia and enhancing physical stability. Dietary-only weight loss in older adults often reduces both fat and muscle mass, potentially exacerbating sarcopenia and frailty. Integrating exercise is therefore essential to preserve muscle and physical function. This randomized controlled trial examined the individual and combined effects of the 5:2 diet and MSE on body composition in older adults with abdominal obesity.
METHODS:
A total of 80 (20 per group) physical inactive older adults (aged 60–75) with abdominal obesity (BMI ≥ 25 kg/m2, waist circumference >80 cm for women and >90 cm for men) were randomly allocated to one of four groups for a 14-week intervention: (1) 5:2 diet group, restricting energy intake to 500–600 kcal on two non-consecutive days per week; (2) MSE group, performing 70-minute training sessions on three non-consecutive days per week; (3) Combined group (5:2 diet + MSE); and (4) Control group. The primary outcomes were body weight (BW), waist circumference (WC), muscle mass percentage. Secondary outcomes included body mass index (BMI), hip circumference (HC), body fat (BF), body fat percentage (BF%), and muscle mass. Linear mixed-effects models were used to do the data analysis.
RESULTS:
Eighty participants completed the 14-week interventions. Compared to the 5:2 diet, MSE, and control groups, the combined group achieved greater reductions in BW, BMI, BF%, and BF, along with a greater increase in muscle mass percentage (all p < 0.001). WC decreased more in the combined group versus all other three groups (all p < 0.05). HC reduction in the combined group was greater compared to the 5:2 and control groups (both p < 0.05), but not versus the MSE group (p = 0.248). For the combined and the 5:2 diet groups, significant decreases were observed in BW (-2.71 kg and -1.69 kg, respectively; both p < 0.001) and BMI (-1.06 kg/m2 and - 0.68 kg/m2, respectively; both p < 0.001), but not in the MSE group (-0.08 kg/m2, p > 0.05). Significant reductions in BF% (-1.89%), BF (-2.30 kg), and significant increase in muscle mass percentage (1.88%) were observed exclusively in the combined group (all p < 0.001), while a significant decrease in muscle mass was found solely in the 5:2 diet group (-0.93 kg) (p < 0.001).
CONCLUSION:
These findings indicate that, for physical inactive older adults with abdominal obesity, a combination of a 5:2 diet and MSE yields superior reductions in body weight and improvements in body composition than either intervention alone. Notably, the combined regimen appears to preserve muscle mass while effectively reducing body fat, whereas the 5:2 diet alone may lead to muscle loss in this population.