Aging, obesity and increased waist circumference (WC) increases risk for metabolic syndrome (MetS). MetS is a cluster of symptoms (elevated WC, triglycerides, blood pressure, fasting glucose, and decreased high-density lipoprotein cholesterol [HDL-C]) increasing risk for chronic disease. Low-energy dense (LED) diets, emphasizing whole food eating patterns, have not been examined in combination with moderate (mod)/high-intensity physical activity (PA) or dietary protein levels to determine their impact on changes in body weight (BW) and WC in premenopausal, abdominally obese women. PURPOSE: To determine the effect of two 16-wk diet and PA interventions, differing in protein intake, on BW, WC, MetS risk factors, dietary patterns, energy density (ED), and min of Mod-Hi PA. METHODS: Healthy, abdominally obese (WC≥80cm) women (n=38; 34±10y) were randomly assigned to either a 15 or 25% (+18 g/d whey protein) en from protein diet. Individualized LED diets plans decreased energy intake (EI) by ~300kcal/d; PA 5 d/wk (30-60 min/d) consisted of supervised, high-intensity Zumba classes 3d/wk (≥65%HRmax; ≥6METs) and self-selected mod-intensity PA (≥3METs) 2d/wk. Servings of fruits/vegetables, whole grains, and low-fat/fat-free dairy (LFD), fiber, high calorie beverages (BEV), ED, and PA were monitored before (T1), during (T2) and after (T3) the intervention using repeated measures ANOVA. Bonferroni simultaneous testing procedure was used in analysis of multiple comparisons. RESULTS: At T1, groups did not differ in dietary patterns, PA, BW, WC, or MetS risk. Groups responded similarly to the interventions so data were combined, with BW and WC decreasing (p<0.0001) by -4.8±2.7kg and -7.1±3.6cm, respectively. Comparing T1 vs. T2, there were increases (p<0.0001) in fruits/vegetables, (Δ=+1.5 ser/d), whole grains (Δ=+1.0 ser/d), LFD (Δ=+0.5 ser/d), fiber (Δ=+5.7g/1000 kcal), and decreases in BEV (Δ=-165 kcal/d) and ED (Δ=-0.55 kcal/g). During the intervention high-intensity Zumba PA was 87min/wk; total min of all mod-intensity PA increased by 75 min/d (p<0.0001); VO2max improved from 29.3±4.7 (T1) to 34.4±5.3 (T3) mL/kg/min (p<0.0001). Triglycerides significantly decreased (-24±52 mg/dl; p=0.006), no other significant changes occurred in MetS risk factors. Exploratory analysis indicated that increases in fruits/vegetables and LFD, and decreases ED were associated with BW loss, while increases in whole grains, fiber, LFD, and min/wk of high-intensity PA (Zumba) were associated with WC reductions. CONCLUSION: For abdominally obese women, an intervention focused on LED foods and high-intensity PA significantly reduced BW and WC and improved dietary patterns regardless of protein intake. Helping clients identify a few key factors that positively promote reductions in BW and WC may improve weight loss success, while reducing MetS risk factors. / Graduation date: 2012