title: Effects of different degrees of insulin resistance on endothelial function in obese adults undergoing alternate day fasting.
abstract: BACKGROUND:Obesity can have deleterious effects on insulin sensitivity leading to endothelial dysfunction. Whether alternate day fasting (ADF) can ameliorate insulin sensitivity in a way that improves endothelial function remains unknown.OBJECTIVE:This study examined the impact of ADF on endothelium dependent flow mediated dilation (FMD) in obese subjects with different degrees of insulin resistance.METHODS:Obese non-diabetic adults (n= 54) participated in an 8-week ADF protocol (25% energy intake "fast day", alternated with ad libitum intake "feast day"). Subjects were divided into tertiles according to degree of insulin resistance based on HOMA-IR (Homeostatic model assessment-Insulin resistance): tertile 1 (0.8-2.4), tertile 2 (2.5-3.6), tertile 3 (3.7-12.4).RESULTS:Body weight decreased (P< 0.001) by 4% in each tertile. Fat mass, lean mass, and visceral fat mass also decreased (P< 0.001) similarly in each tertile. After 8 weeks of ADF, FMD and adiponectin differed (P< 0.05) between tertile 1 (3±0%; 26±23%) versus tertile 3 (-3±0%; -13±10%). Changes in leptin did not differ between tertiles (tertile 1: -23±7%; tertile 2: -20±7%; tertile 3: -9±7%). Fasting glucose did not change in any tertile. Fasting insulin and HOMA-IR differed (P< 0.05) between tertile 1 (10±11%; 11±11%) versus tertile 3 (-27±8%; -30±9%). Plasma lipids, blood pressure and heart rate did not change in any tertile.CONCLUSION:Our data suggest that ADF may be effective for decreasing insulin resistance in insulin resistant subjects, but these changes have no effect on endothelial function.
authors.affiliation: Department of Kinesiology and Nutrition, University of Illinois at Chicago , Chicago, IL, USA.
authors.forename: Kristin K
authors.initials: KK
authors.lastname: Hoddy
authors.affiliation: Department of Kinesiology and Nutrition, University of Illinois at Chicago , Chicago, IL, USA.
authors.forename: Surabhi
authors.initials: S
authors.lastname: Bhutani
authors.affiliation: Department of Physical Therapy, University of Illinois at Chicago , Chicago, IL, USA.
authors.forename: Shane A
authors.initials: SA
authors.lastname: Phillips
authors.affiliation: Department of Kinesiology and Nutrition, University of Illinois at Chicago , Chicago, IL, USA.
authors.forename: Krista A
authors.initials: KA
authors.lastname: Varady
keywords: Alternate day fasting; adipokines; coronary heart disease; endothelial function; insulin resistance; weight loss