Exercise and Diet Responses in Adult Men With Obesity by MC4R Genotype and Metabolic Health

Overview

This study evaluated whether differences in the MC4R rs17782313 gene variant and metabolic health status were associated with different responses to a 12-week exercise and dietary intervention in adult men with obesity. A total of 40 men aged 18 to 59 years with obesity participated in the study. At baseline, participants were classified as having metabolically healthy obesity or metabolically unhealthy obesity according to metabolic risk factors. All participants received the same supervised lifestyle intervention, which included aerobic exercise, resistance training, and an individualized energy-controlled diet. Body weight, body composition, physical fitness, blood pressure, blood glucose, blood lipids, glycated hemoglobin, and fasting insulin were measured before and after the 12-week intervention. Blood samples were also collected for MC4R rs17782313 genotyping. The study examined whether changes after the intervention differed according to baseline metabolic phenotype and MC4R genotype.

This was a completed, single-center lifestyle intervention study involving adult men with obesity in Harbin, China. Eligible participants were men aged 18 to 59 years with a body mass index of at least 28 kg/m2 and a waist circumference of at least 90 cm. At baseline, participants were classified as having metabolically healthy obesity or metabolically unhealthy obesity using criteria based on the National Cholesterol Education Program Adult Treatment Panel III. Metabolically unhealthy obesity was defined as obesity accompanied by at least two of the following metabolic abnormalities: elevated blood pressure, elevated fasting blood glucose, elevated triglycerides, or reduced high-density lipoprotein cholesterol. Metabolically healthy obesity was defined as obesity accompanied by no more than one of these abnormalities. All participants received the same 12-week supervised exercise and dietary intervention. The exercise program was conducted 5 days per week and consisted of aerobic exercise performed at approximately 60% to 70% of maximum heart rate and resistance exercise performed at approximately 40% to 60% of one-repetition maximum. Daily energy intake was individualized according to standard body weight. The planned macronutrient distribution was approximately 50% to 60% of energy from carbohydrates, 15% to 20% from protein, and 20% to 30% from fat. Anthropometric and body-composition assessments included body weight, body mass index, fat mass, body fat percentage, muscle mass, waist circumference, hip circumference, and waist-to-hip ratio. Physical fitness assessments included vital capacity, handgrip strength, vertical jump, push-ups, sit-ups, sit-and-reach flexibility, one-leg standing with eyes closed, choice reaction time, and back strength. Physiological and biochemical assessments included resting heart rate, systolic and diastolic blood pressure, fasting blood glucose, triglycerides, total cholesterol, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, glycated hemoglobin, and fasting insulin. Measurements were conducted at baseline and after 12 weeks. MC4R rs17782313 genotype and baseline metabolic phenotype were analytical stratification variables. They were not used to assign different interventions. The study evaluated changes from baseline to week 12 and examined whether intervention responses were associated with metabolic phenotype, MC4R genotype, or their interaction.