Weight Loss-Independent Effect of Calorie Restriction on Insulin Sensitivity and Postprandial Incretin Hormones

The number of older obese adults is increasing worldwide. Whether obese adults show similar health benefits in response to lifestyle interventions at different ages is unknown. The study enrolled 25 obese men (BMI 31-39 kg/m2) in two arms according to age (30-40 and 60-70 years old). Participants underwent an 8-week intervention with moderate calorie restriction (~20% below individual energy requirements) and supervised endurance training resulting in ~5% weight loss. Body composition was measured using dual energy X-Ray absorptiometry. Insulin sensitivity was assessed during a hypersinsulinemic euglycemic clamp. Cardiometabolic profile was derived from blood parameters. Subcutaneous fat and vastus lateralis muscle biopsies were used for ex vivo analyses. Two-way repeated-measure ANOVA and linear mixed models were used to evaluate the response to lifestyle intervention and comparison between the two groups. Fat mass was decreased and bone mass was preserved in the two groups after intervention. Muscle mass decreased significantly in older obese men. Cardiovascular risk (Framingham risk score, plasma triglyceride and cholesterol) and insulin sensitivity were greatly improved to a similar extent in the two age groups after intervention. Changes in adipose tissue and skeletal muscle transcriptomes were marginal. Analysis of the differential response to the lifestyle intervention showed tenuous differences between age groups. These data suggest that lifestyle intervention combining calorie restriction and exercise shows similar beneficial effects on cardiometabolic risk and insulin sensitivity in younger and older obese men. However, attention must be paid to potential loss of muscle mass in response to weight loss in older obese men.

Download Full-text

Does Regular Exercise without Weight Loss Reduce Insulin Resistance in Children and Adolescents?

International Journal of Endocrinology ◽

10.1155/2013/402592 ◽

2013 ◽

Vol 2013 ◽

pp. 1-10 ◽

Cited By ~ 9

Author(s):

YoonMyung Kim ◽

HaNui Park

Keyword(s):

Insulin Resistance ◽

Weight Loss ◽

Childhood Obesity ◽

Insulin Sensitivity ◽

Exercise Training ◽

Calorie Restriction ◽

Pediatric Population ◽

Optimal Dose ◽

Regular Exercise ◽

Type Of Exercise

Despite considerable efforts to tackle childhood obesity, it is recognized as one of the biggest health problems globally. Childhood obesity is a leading cause of many comorbid conditions such as metabolic syndrome and insulin resistance as well as type 2 diabetes. A strong body of evidence suggests that regular exercise without calorie restriction or weight loss is associated with reduced insulin resistance as well as improved insulin sensitivity in overweight and obese adults. However, despite the well-known benefits associated with regular exercise alone, the independent role of exercise training without calorie restriction on insulin resistance is still uncertain in youth. Some studies observed that both the aerobic and resistance type of exercise training without calorie restriction resulted in meaningful changes in insulin sensitivity, suggesting that exercise alone is an effective therapeutic strategy for reducing insulin resistance in overweight and obese youth. However, only few studies are available on the optimal dose of exercise training without calorie restriction or preferred exercise modality for reducing insulin resistance, which warrants further investigations in the pediatric population.

Download Full-text