This project is prompted by the urgent public health need to find optimal nutrition and exercise prevention strategies to reduce future cardiovascular disease and type 2 diabetes risk in young adults. This project aims to investigate the efficacy of a low-glycemic load diet both alone, and in combination with resistance training, to ameliorate endothelial dysfunction, monocyte inflammation and 24-hr glycemic variations. 160 obese young adults will be randomly assigned to 1 of 4 groups for 12 weeks: 1) a control high-glycemic load diet;2) a low- glycemic load diet;3) a high-glycemic load diet + resistance training;or 4) low-glycemic load diet + resistance training.
The aims are to determine if: 1) a low-GL diet improves endothelial function, monocyte inflammation and 24-hr glycemic variations compared to a standard high-glycemic load, Westernized diet and 2) a low-GL diet + RT has an additive effect with low-GL diet to improve endothelial function, monocyte inflammation and 24-hr glycemic variations. Dependent variables include endothelial function by brachial artery flow-mediated dilation (FMD), monocyte phenotyping by flow cytometry and PCR/protein analysis, 24-hr continuous glucose monitoring systems, insulin sensitivity by frequently sampled intravenous glucose tolerance test, whole body composition by DEXA, visceral and hepatic fat fraction by MRI, and acute responses to a high-glycemic index meal. The hypotheses are that a low-glycemic load diet will improve the above key cardiovascular risk related dependent variables and that the addition of resistance training will induce additive effects. This project will, for the first time, compare the isolated and combined effects of a low-glycemic load diet and/or resistance training on endothelial function, monocyte inflammation and 24-hr glycemic variations. If the hypotheses are upheld, new therapeutic options will become available to improve primary prevention of vascular dysfunction, chronic inflammation and insulin resistance, including in those young adults where alternative therapies may be less effective.

Public Health Relevance

For the first time, a randomized controlled trial using a low glycemic-load diet and/or resistance training will be carried out in obese young men and women. This efficacy trial should have major public health implications to the tens of millions of Americans currently obese, presenting with less than optimal vascular function, chronic inflammatory status and insulin sensitivity, thus providing insight into novel preventive health strategies. Furthermore, due to individualized specificity of compliance issues for each patient, the arsenal of therapies for prescription needs to be large;the current proposal will potentially increase the range of therapies.

National Institute of Health (NIH)
National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
Research Project (R01)
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Study Section
Kidney, Nutrition, Obesity and Diabetes (KNOD)
Program Officer
Bremer, Andrew
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University of California Los Angeles
Schools of Nursing
Los Angeles
United States
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Roberts, Christian K; Lee, Mary M; Katiraie, Michael et al. (2015) Strength fitness and body weight status on markers of cardiometabolic health. Med Sci Sports Exerc 47:1211-8
Wilson, Neil E; Burns, Brian L; Iqbal, Zohaib et al. (2015) Correlated spectroscopic imaging of calf muscle in three spatial dimensions using group sparse reconstruction of undersampled single and multichannel data. Magn Reson Med 74:1199-208
Croymans, D M; Krell, S L; Oh, C S et al. (2014) Effects of resistance training on central blood pressure in obese young men. J Hum Hypertens 28:157-64
Kelesidis, Theodoros; Roberts, Christian K; Huynh, Diana et al. (2014) A high throughput biochemical fluorometric method for measuring lipid peroxidation in HDL. PLoS One 9:e111716
Furuyama, Jon K; Nagarajan, Rajakumar; Roberts, Christian K et al. (2014) A pilot validation of multi-echo based echo-planar correlated spectroscopic imaging in human calf muscles. NMR Biomed 27:1176-83
Croymans, Daniel M; Paparisto, Ergit; Lee, Mary M et al. (2013) Resistance training improves indices of muscle insulin sensitivity and ?-cell function in overweight/obese, sedentary young men. J Appl Physiol (1985) 115:1245-53
Roberts, Christian K; Katiraie, Michael; Croymans, Daniel M et al. (2013) Untrained young men have dysfunctional HDL compared with strength-trained men irrespective of body weight status. J Appl Physiol (1985) 115:1043-9
Roberts, Christian K; Little, Jonathan P; Thyfault, John P (2013) Modification of insulin sensitivity and glycemic control by activity and exercise. Med Sci Sports Exerc 45:1868-77
Roberts, Christian K; Hevener, Andrea L; Barnard, R James (2013) Metabolic syndrome and insulin resistance: underlying causes and modification by exercise training. Compr Physiol 3:1-58
Jeon, Christie Y; Roberts, Christian K; Crespi, Catherine M et al. (2013) Elevated liver enzymes in individuals with undiagnosed diabetes in the U.S. J Diabetes Complications 27:333-9

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