High-intensity exercise and carbohydrate-reduced energy-restricted diet in obese individuals

Abstract

Continuous high glycemic load and inactivity challenge glucose homeostasis and fat oxidation. Hyperglycemia and high intramuscular glucose levels mediate insulin resistance, a precursor state of type 2 diabetes. The aim was to investigate whether a carbohydrate (CHO)-reduced diet combined with high-intensity interval training (HIIT) enhances the beneficial effects of the diet alone on insulin sensitivity and fat oxidation in obese individuals. Nineteen obese subjects underwent 14 days of CHO-reduced and energy-restricted diet. Ten of them combined the diet with HIIT (4 min bouts at 90% VO(2peak) up to 10 times, 3 times a week). Oral glucose insulin sensitivity (OGIS) increased significantly in both groups; [diet-exercise (DE) group: pre 377 ± 70, post 396 ± 68 mL min(-1) m(-2); diet (D) group: pre 365 ± 91, post 404 ± 87 mL min(-1) m(-2); P < 0.001]. Fasting respiratory exchange ratio (RER) decreased significantly in both groups (DE group: pre 0.91 ± 0.06, post 0.88 ± 0.06; D group: pre 0.92 ± 0.07, post 0.86 ± 0.07; P = 0.002). VO(2peak) increased significantly in the DE group (pre 27 ± 5, post 32 ± 6 mL kg(-1) min(-1); P < 0.001), but not in the D group (pre 26 ± 9, post 26 ± 8 mL kg(-1) min(-1)). Lean mass and resistin were preserved only in the DE group (P < 0.05). Fourteen days of CHO-reduced diet improved OGIS and fat oxidation (RER) in obese subjects. The energy-balanced HIIT did not further enhance these parameters, but increased aerobic capacity (VO(2peak)) and preserved lean mass and resistin.

Adaptive metabolic response to 4 weeks of sugar-sweetened beverage consumption in healthy, lightly active individuals and chronic high glucose availability in primary human myotubes

“…The diet analysis was conducted using the United States Department of Agriculture food search for windows, Version 1.0, database version SR21 in combination with nutritional information labels. Lean mass, fat mass and bone mineral content were assessed by Dual-energy X-ray Absorptiometry (DXA) (QDR1500, software version 5-72; Hologic, Waltham, MA, USA) as described previously [22]. …”

“…Densitometry was then used to quantify protein bands (Gel Doc 2000 and software Quantity One-4.6.3, Bio-Rad, Hercules, CA, USA). MHC extraction and electrophoresis were executed as described in Sartor et al [22]. …”

Effect of Creatine Supplementation on Exercise Performance following a Short-term Low Carbohydrate Diet

“…In order to improve VO2max it may be necessary to train near or at VO2max (Esfarjani & Laursen, 2007). It is thought that a HIIT training program may induce adaptations that would increase an individual's VO2max and overall fitness (Esfarjani & Laursen, 2007;Sartor et al, 2010). For instance, in a study by Sartor et al (2010), HIIT was effective in increasing VO2peak by 16% (on average) in two weeks of training.…”

“…It is thought that a HIIT training program may induce adaptations that would increase an individual's VO2max and overall fitness (Esfarjani & Laursen, 2007;Sartor et al, 2010). For instance, in a study by Sartor et al (2010), HIIT was effective in increasing VO2peak by 16% (on average) in two weeks of training. An improvement in overall fitness and VO2max may increase the basal metabolic rate of the individual, lending to greater caloric expenditure during exercise, as much as a proposed 33% (Esfarjani & Laursen, 2007;Hunter et al, 1998;Perry et al, 2008;Sartor et al, 2010).…”

Skeletal Muscle, Myokines and Health

“…Several adipokines, including resistin and TNF-α have been implicated in the impairment of insulin sensitivity, while leptin and adiponectin are generally believed to exert an insulin sensitizing effect. Leptin resistance can be modulated by both diet and training in rodents [47] and humans [52]. The effects of these adipokines on metabolism and insulin sensitivity are generally studied in isolation [47]; in future, ours understand the interaction amongst the adipokines will be a most difficult task.…”