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Background/ObjectivesA diet rich in dairy and calcium (Ca) has been variably associated with improvements in body composition and decreased risk of type 2 diabetes. Our objective was to determine if a dietary pattern high in dairy and Ca improves weight loss and subjective appetite to a greater extent than a low dairy/Ca diet during energy restriction in overweight and obese adults with metabolic syndrome.Subjects/Methods49 participants were randomized to one of two treatment groups: CONTROL [low dairy, ~700 mg/day Ca, −500 kcal/d] or DAIRY/CA [high dairy, ~1400 mg/day Ca, −500 kcal/d] for 12wk. Body composition, subjective ratings of appetite, food intake, plasma satiety hormones, glycemic response and inflammatory cytokines were measured.ResultsCONTROL (−2.2±0.5 kg) and DAIRY/CA (−3.3±0.6 kg) had similar weight loss. Based on self-reported energy intake, the percent of expected weight loss achieved was higher with DAIRY/CA (82.1±19.4%) than CONTROL (32.2±7.7%)(P=0.03). Subjects in the DAIRY/CA group reported feeling more satisfied (P=0.01) and had lower dietary fat intake (P=0.02) over 12wk compared to CONTROL. Compared to CONTROL, DAIRY/CA had higher plasma levels of peptide tyrosine tyrosine (PYY, P=0.01) during the meal tolerance test at wk12. Monocyte chemoattractant protein-1 was reduced at 30 min with DAIRY/CA compared to CONTROL (P=0.04).ConclusionsIn conclusion, a dairy and Ca rich diet was not associated with greater weight loss than control. Modest increases in plasma PYY concentrations with increased dairy/Ca intake, however, may contribute to enhanced sensations of satisfaction and reduced dietary fat intake during energy restriction. Registered Trial: ClinicalTrials.gov (NCT00564551).

Objective: Oligofructose (OFS) is a prebiotic that reduces energy intake and fat mass via changes in gut satiety hormones and microbiota. The effects of OFS may vary depending on predisposition to obesity. The aim of this study was to examine the effect of OFS in diet-induced obese (DIO) and diet-resistant (DR) rats. Methods: Adult, male DIO, and DR rats were randomized to: (1) high-fat/high-sucrose (HFS) diet or (2) HFS diet 1 10% OFS for 6 weeks. Body composition, food intake, gut microbiota, plasma gut hormones, and cannabinoid CB 1 receptor expression in the nodose ganglia were measured. Results: OFS reduced body weight, energy intake, and fat mass in both phenotypes (P < 0.05). Select gut microbiota differed in DIO versus DR rats (P < 0.05), the differences being eliminated by OFS. OFS did not modify plasma ghrelin or CB 1 expression in nodose ganglia, but plasma levels of GIP were reduced and PYY were elevated (P < 0.05) by OFS. Conclusions: OFS was able to reduce body weight and adiposity in both prone and resistant obese phenotypes. OFS-induced changes in gut microbiota profiles in DIO and DR rats, along with changes in gut hormone levels, likely contribute to the sustained lower body weights.

Evidence suggests that dietary calcium (Ca) and particularly dairy foods may attenuate weight gain and improve symptoms of the metabolic syndrome. The purpose of this study was to determine the effect of different Ca‐enriched dairy protein sources on the prevention of weight gain in Sprague‐Dawley diet‐induced obese (DIO) rats. Twelve week‐old DIO rats were assigned to one of eight ad libitum diets that varied in protein source (casein, whey, or complete dairy), Ca content (0.67 or 2.4%) and energy level (high fat/high sucrose (HFHS); or normal calorie density (NC)). Body composition and response to a meal tolerance test (MTT) were measured. Average daily caloric intake did not differ within normal or high energy density groups. At the end of 8 weeks, the dairy/HFHS/0.67% and 2.4% groups had significantly lower body weight than all other HFHS groups. The dairy/HFHS/0.67% and 2.4% groups also had lower body fat and greater lean mass expressed as a percent (P < 0.05). Homeostatic model assessment of insulin resistance (HOMAIR) was lowest for dairy/HFHS/0.67% and significantly different from whey/HFHS/0.67% and 2.4%. Independent of protein source, high Ca decreased plasma insulin at 30 min in the MTT more so than low Ca (P < 0.05). Hepatic sterol regulatory element–binding protein (SREBP1c) and peroxisome proliferator–activated receptor‐γ (PPARγ) mRNA was downregulated by dairy and whey compared to casein in the HFHS/0.67% diets. Overall, these data suggest that complete dairy improves body composition and insulin sensitivity to a greater extent than whey or casein alone.

Given the intimate link between gut microbiota and host physiology, there is growing interest in understanding the mechanisms by which diet influences gut microbiota and affects human metabolic health. Using antibiotics and the prebiotic oligofructose, which has been shown to counteract excess fat mass, we explored the gut microbiota-dependent effects of oligofructose on body composition and host metabolism. Diet-induced obese male Sprague Dawley rats, fed a background high-fat/sucrose diet, were randomized to one of the following diets for 6 wk: 1) high-energy control; 2) 10% oligofructose; 3) ampicillin; 4) ampicillin + 10% oligofructose; 5) ampicillin/neomycin; or 6) ampicillin/neomycin + 10% oligofructose. Combining oligofructose with ampicillin treatment blunted the decrease in adiposity seen with oligofructose. Although ampicillin did not affect total bacteria, ampicillin impeded oligofructose-induced increases in Bifidobacterium and Lactobacillus In contrast, the combination of ampicillin and neomycin reduced total bacteria but did not abrogate the oligofructose-induced decrease in adiposity. Oligofructose-mediated effects on host adiposity and metabolic health appear to be in part dependent on the presence of specific microbial species within the gut.-Bomhof, M. R., Paul, H. A., Geuking, M. B., Eller, L. K., Reimer, R. A. Improvement in adiposity with oligofructose is modified by antibiotics in obese rats.