The effect of a very low-calorie diet (VLCD) with and without concomitant resistance exercise training (RET) or high-intensity interval training (HIIT) on body composition, muscle function and metabolism

Abstract

Background: Weight loss is beneficial for health in many aspects, including reducing the risk of various diseases such as type 2 diabetes mellitus, cardiovascular disease, respiratory problems and many more. A very low-calorie diet is one of the methods that can provide rapid weight loss. Unfortunately, there are concerns regards to muscle and lean mass loss with the weight loss process. Exercises particularly resistant exercise training (RET) is known to stimulate muscle growth; however, research combining RET with VLCD is scarce. High-intensity interval training (HIIT) has recently emerged as an ‘efficient’ exercise that can fit many busy lifestyles. However, no study has been done to combine HIIT with VLCD to compare its benefit with diet only or with RET. Objectives: To assess for any significant differences in the outcomes from VLCD only, VLCD with RET and VLCD with HIIT interventions, focusing on changes in lean and muscle mass, muscle protein synthesis rate, muscle function in the form of muscle strength, metabolic markers including lipid profiles and glucose homeostasis, cardiovascular function, and cardiorespiratory fitness. Design: Overweight/obese (BMI≥27) middle age (30 to 60-year old) males were recruited, randomly assigned to three groups either VLCD only (VLCD+O), VLCD with RET (VLCD+R) or VLCD+HIIT (VLCD+H). Interventions were for six weeks. Investigations and procedures include DXA scan, ultrasound scan of muscle structure and blood flow, echocardiogram of the heart, oral glucose tolerance test for insulin and glucose level, blood sampling, saliva collection and muscle biopsy involving stable isotope deuterium oxide to measure muscle protein synthesis rate. Conclusion: All groups showed significant total weight, fat mass, and lean mass loss. Despite the lean mass loss, all groups had improvement in metabolic markers, including glucose homeostasis and lipid profiles and had no reduction in muscle strength. Incorporating HIIT with VLCD showed a statistically significant higher muscle protein synthesis rate compared to VLCD alone while incorporating RET showed a significant increase in strength compared to the other groups