Effects of Combined High-Protein Diet and Exercise Intervention on Cardiometabolic Health in Middle-Aged Obese Adults: A Randomized Controlled Trial

Abstract

Background: Obesity is the main risk factor of cardiovascular diseases (CVD) and metabolic diseases. The middle-aged population is the age group with the highest prevalence of obesity. Thus, improving cardiometabolic health is important to prevent CVD and metabolic diseases in middle-aged obese adults. The aim of this study was to examine the effects of exercise alone or in combination with a high-protein diet on markers of cardiometabolic health in middle-aged adults with obesity.Methods: Sixty-nine middle-aged adults with obesity were assigned randomly to the control group (C; n = 23), exercise group (E; n = 23), or exercise combined with high-protein diet group (EP; n = 23). Individuals in the E and EP groups received supervised exercise training and individuals in the EP group received high-protein diet intervention. Body composition (assessed by dual-energy X-ray absorptiometry), oral glucose tolerance test (OGTT), lipid profiles, and inflammatory markers were determined before and after 12 weeks of intervention. Insulin sensitivity index (ISI0,120) was calculated from values of fasting and 2-h insulin and glucose concentration of OGTT. Insulin-peak-time during the OGTT was recorded to reflect β-cell function. Analysis of covariance with baseline values as covariates was used to examine the effects of the intervention. The significant level was set at 0.05.Results: After 12 weeks of intervention, the E group had a greater percentage of individuals with early insulin-peak-time during the OGTT than that in the C and EP groups (p = 0.031). EP group had lower total cholesterol and triglycerides than that in the C group (p = 0.046 and 0.014, respectively). Within-group comparisons showed that the 2-h glucose of OGTT and C-reactive protein decreased in the EP group (p = 0.013 and 0.008, respectively) but not in the E and C groups; insulin sensitivity improved in the EP group (p = 0.016) and had a trend to improve in the E group (p = 0.052); and abdominal fat mass and total body fat mass decreased in both intervention groups (p < 0.05).Conclusion: Combined high-protein diet and exercise intervention significantly decreased fat mass and improved lipid profiles, insulin sensitivity, glucose tolerance, and inflammation in middle-aged adults with obesity.Clinical Trial Registration: Thai Clinical Trials Registry, TCTR20180913003, 13-09-2018.

The Impact of High Protein Diets on Cardiovascular Outcomes: A Systematic Review and Meta-Analysis of Prospective Cohort Studies

“…Over the last years, HP diets have been suggested as healthier alternatives that contribute to achieving sustained weight loss or improving muscle mass, while simultaneously preserving good cardiovascular and skeletomuscular health. However, available evidence from cohort studies seems quite controversial, with the majority of studies showing a positive impact of HP diets on cardiometabolic risk reduction, both in apparently healthy populations and in people at a high risk of, or with already established, CVD [ 9 , 10 , 11 , 12 , 13 , 14 , 15 , 16 , 17 ]. On the other hand, some studies demonstrated a negative impact of HP diets on cardiometabolic profile [ 18 , 19 ] and regarding hard cardiovascular and renal outcomes [ 20 , 21 , 22 , 23 , 24 , 25 , 26 ].…”

“…HP diets, with or without the restriction of carbohydrate intake, have gained increased popularity because they are being promoted as a means of losing weight, increasing muscle mass and strength, preserving a functional skeletomuscular system, improving cardiometabolic parameters, and even cardiovascular outcomes, both in apparently healthy populations and in people at high risk of, or with already established, CVD [ 9 , 10 , 11 , 12 , 13 , 14 , 15 , 16 , 17 ]. On the other hand, there are studies that appear to associate increased protein consumption with unfavorable metabolic profiles, development, or deterioration of type 2 diabetes mellitus (T2DM) [ 18 , 19 ], worse cardiovascular and renal outcomes [ 20 , 21 , 22 ], and even with higher all-cause and cause-specific mortality, focusing on cancer and CVD [ 23 , 24 , 25 , 26 ].…”

“…Based on energy intake, they vary from 15% up to 30% including both clinical studies and meta-analyses [ 7 , 10 , 29 , 42 , 43 ]. Based on grams of protein per kg of body weight (BW), high protein diets seem to range from 1.2 to 1.6 g/kg/day [ 9 ].…”