Positive Effects of Aerobic-Resistance Exercise and an Ad Libitum High-Protein, Low-Glycemic Index Diet on Irisin, Omentin, and Dyslipidemia in Men with Abdominal Obesity: A Randomized Controlled Trial

The aim of this research was to evaluate changes in body composition, adipokine levels, and dyslipidemia parameters in males with abdominal obesity following two distinct interventions: exercise alone and exercise combined with an ad libitum diet. This study included 44 males with abdominal obesity (mean age 34.7 ± 5.5 years, waist circumference [WC] 110.3 ± 8.5, BMI 32.0 ± 3.9), who were randomly assigned to three groups: an experimental group engaging in aerobic-resistance exercise (II, = 16), an experimental group engaging in aerobic-resistance exercise combined with an ad libitum high-protein, low-glycemic index carbohydrate diet (III, = 16), both interventions lasting 6 weeks, and a control group without interventions (I, = 12). Body composition metrics (body mass index [BMI], waist circumference [WC], body fat [BF], abdominal fat [ABD]) and fat-free mass [FFM], along with biochemical blood analyses (irisin [IR], omentin [OMEN], glucose [GLU], insulin [INS], LDL- and HDL-cholesterol), were measured at baseline and after the 6-week intervention. The effects of the interventions on the analyzed variables across groups were assessed using mixed ANOVA tests with post-hoc comparisons. Effect size (ES) was also calculated using partial eta squared ( p ). The intervention in group III resulted in a significant decrease in IR ( < 0.01, p = 0.03) by 41% and LDL-C ( < 0.01, p = 0.02) by 14%. These effects were associated with a reduction in BF ( < 0.01, p = 0.02) by 14%, ABD ( < 0.01, p = 0.03) by 31%, and WC ( < 0.01, p = 0.01) by 3%. In group II, decreases after 6 weeks of intervention were noted only in WC ( = 0.02, p = 0.01) by 1% and in INS ( < 0.01, p = 0.04) by 47%. No differences were found between groups. The use of low-glycemic index carbohydrates ( < 0.01, p = 0.06) and increased protein intake ( < 0.01, p = 0.30) led to changes in the fiber-to-energy value of the diet ratio ( < 0.01, p = 0.18) and a reduction in dietary energy value ( < 0.01, p = 0.13) by 23%, resulting in a greater energy deficit than in the II group. These findings highlight the effect of combining dietary and exercise interventions to achieve significant changes in body composition and metabolic parameters, even over a short period of intervention.