Plain language summary
Diets high in poor quality carbohydrates and fats and low in fibre are believed to play an integral role in the formation of many different chronic diseases. Calorie restricted diets have previously shown to have health benefits, but these are stringent and hard to maintain. More recently low-carbohydrate diets have shown that they may be better tolerated. This randomised control trial aimed to compare a calorie restricted diet (MixD) with a calorie restricted moderate-carbohydrate diet (MCD) on indicators for chronic disease in 60 overweight and obese men over four weeks. The results showed that MCD resulted in significant loss of body fat without loss of muscle mass compared to MixD and significantly decreased markers for heart disease risk. It was concluded that the amount of body fat can be attributed to the amount and quality of carbohydrates consumed and that consumption of a MCD is more effective for weight loss without compromising muscle mass than a MixD. This study could be used by health professionals to recommend a MCD to middle aged obese men in order to lose body fat, retain muscle mass and reduce their risk of heart disease.
Abstract
Carbohydrate-restricted diets have become very popular due to their numerous health benefits. The aim of this study was to determine the influence of 4 weeks of a well-planned, low-energy moderate-carbohydrate diet (MCD) and a low-energy mixed diet (MixD) on the lipoprotein profile, glucose and C-reactive protein concentrations, body mass, and body composition in middle-aged males. Sixty middle-aged males were randomly assigned to the following groups: hypocaloric MCD (32% carbohydrates, 28% proteins, and 40% fat), hypocaloric MixD (50% carbohydrates, 20% proteins, and 30% fat), and a conventional (control) diet (CD; 48% carbohydrates, 15% proteins, and 37% fat). The participants who were classified into the MCD and MixD groups consumed 20% fewer calories daily than the total daily energy expenditure (TDEE). Baseline and postintervention fasting triacylglycerol (TG), LDL (low-density lipoprotein) cholesterol (LDL-C), HDL (high-density lipoprotein) cholesterol (HDL-C), total cholesterol (tCh), glucose (Gl), and C-reactive protein were evaluated. Body mass (BM) and body composition changes, including body fat (BF), % body fat (PBF), and muscle mass (MM), were monitored. Compared with MixD and CD, MCD significantly changed the fasting serum concentrations of TG (p < 0.05), HDL-C (p < 0.05), LDL-C (p < 0.05), tCh (p < 0.05), and glucose (p < 0.01). Additionally, body fat content (kg and %) was significantly reduced (p < 0.05) after MCD compared with MixD and CD. After the MixD intervention, BM and MM decreased (p < 0.05) compared with baseline values. Compared with baseline, after the MixD, BM, MM, tCh, LDL-C, and TG changed significantly. The 4 week low-energy MCD intervention changed lipoproteins, glucose, and body fat to a greater extent than the low-energy MixD. A hypocaloric MCD may be suggested for middle-aged male subjects who want to lose weight by reducing body fat content without compromising muscle mass.
Methodological quality
Jadad score
:
2
Allocation concealment
:
No
