Non-Energy-Restricted Low-Carbohydrate Diet Combined with Exercise Intervention Improved Cardiometabolic Health in Overweight Chinese Females

Abstract

This study aimed to examine the effects of four weeks of a low-carbohydrate diet (LC) and incorporated exercise training on body composition and cardiometabolic health. Fifty-eight overweight/obese Chinese females (age: 21.2 ± 3.3 years, body mass index (BMI): 25.1 ± 2.8 kg/m 2 ) were randomly assigned to the control group (CON, n = 15), the LC control group (LC-CON, n = 15), the LC and high-intensity interval training group (LC-HIIT, n = 15), or the LC and moderate-intensity continuous training group (LC-MICT, n = 13). Subjects consumed a four week LC, whereas LC-HIIT and LC-MICT received extra training 5 d/week (LC-HIIT: 10 × 6 s cycling interspersed with 9 s rest, MICT: 30 min continuous cycling at 50-60% VO 2peak ). After intervention, the three LC groups demonstrated significant reductions in body weight (−2.85 kg in LC-CON, −2.85 kg in LC-HIIT, −2.56 kg in LC-MICT, p < 0.001, η 2 = 0.510), BMI (p < 0.001, η 2 = 0.504) and waist-to-hip ratio (p < 0.001, η 2 = 0.523). Groups with extra training (i.e., LC-HIIT and LC-MICT) improved VO 2peak by 14.8 and 17.3%, respectively. However, fasting glucose and blood lipid levels remained unchanged in all groups. Short-term LC is a useful approach to improve body composition in overweight/obese Chinese females. Incorporated exercise training has no additional effects on weight loss, but has additional benefits on cardiorespiratory fitness, and HIIT is more time efficient than the traditional MICT (2.5 min vs. 30 min).Nutrients 2019, 11, 3051 2 of 15 (LCs). Emerging evidence mainly derived from western countries has clearly shown that LCs could be effective dietary strategies for weight loss and the management of several common and rare pathological conditions [7][8][9][10][11][12][13]. A meta-analysis has revealed that LCs had greater long-term effects on weight loss when compared to the traditional low-fat diets; furthermore, triglycerides, high-density lipoprotein cholesterol (HDL-C), and blood pressure values were also more favorably altered in LCs [7]. Additionally, LC-induced weight loss is generally accompanied with several positive metabolic changes, including improvements in blood pressure, glycaemic control, insulin sensitivity, and serum concentrations of C-reactive protein and certain lipids [8][9][10][11][12], which may have the potential to alleviate the features of metabolic disorder and reduce the risk factors associated with developing CVD and T2D. However, limited studies have tested whether LCs are also useful and feasible for the large Chinese overweight/obese population [11,13] given that people in China and in Western countries have distinct dietary patterns and preferences [14,15], which may lead to different levels of acceptance toward LCs. Furthermore, previous LC trials were invariably administered ad libitum without fixed daily energy intakes, or had an overemphasis on energy restriction [8,[10][11][12]16,17]. Undeniably, this approach is more effective and easier to implement in public practice, where researchers are unable to provide strict c...

Impact of a Ketogenic Diet on Metabolic Parameters in Patients with Obesity or Overweight and with or without Type 2 Diabetes: A Meta-Analysis of Randomized Controlled Trials

“…In terms of inclusion criteria regarding baseline comorbidity, 8 studies enrolled T2DM patients [ 21 , 23 , 25 , 26 , 27 , 28 , 30 , 32 ] (in 2 studies prediabetic patients were also included) [ 26 , 27 ], whereas the remaining 6 studies incorporated non-diabetic patients [ 22 , 24 , 29 , 31 , 33 , 34 ]. Seven trials were conducted in the United States [ 26 , 27 , 28 , 31 , 32 , 33 , 34 ]; 2 in Spain [ 21 , 25 ]; and 1 in Norway [ 22 ], Canada [ 23 ], Greece [ 24 ], China [ 29 ], and Australia [ 30 ] each. There was no significant between-group difference in serum levels of FG at pretreatment state in each study, with the mean value ranging from 84.3 to 185 mg/dL in ketogenic diet groups and from 80.2 to 170 mg/dL in comparator groups.…”

“…The inclusion criteria with respect to age, BMI, or HgA1c at baseline appeared varied in each study, which are summarized in Table 1 . One study included female patients only [ 29 ]. Adverse effects were reported in only one study [ 21 ].…”

“…Eight studies reported changes in weight-related parameters post the dietary intervention [ 21 , 24 , 26 , 27 , 28 , 29 , 32 , 34 ]. Meta-analysis demonstrated that ketogenic diet patients were more likely to experience a greater weight reduction compared to those on comparator diets (SMD, −0.46; 95% CI, −0.90 to −0.03; I 2 = 78%; moderate to low quality evidence) ( Figure 4 ).…”

Effects of Combined Exercise and Low Carbohydrate Ketogenic Diet Interventions on Waist Circumference and Triglycerides in Overweight and Obese Individuals: A Systematic Review and Meta-Analysis

“…The titles and abstracts from the initial screening were reviewed and 3007 studies, which were review studies, pilot studies, or not related to this meta-analysis, were excluded. Full texts of the remaining 38 studies were reviewed to determine eligibility, and finally, seven studies were selected [ 16 , 17 , 18 , 19 , 20 , 21 ]. A total of 255 overweight and obese individuals were included in this meta-analysis.…”

“…Participating in combined exercise and low carbohydrate ketogenic diet interventions helped reduce waist circumference in overweight and obese individuals. No meta-analysis of these effects has been reported previously, and several individual previous studies were conflicting [ 17 , 18 ]. The current meta-analysis found decreased waist circumference in the combined exercise and low carbohydrate ketogenic diet intervention groups compared to control groups.…”