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Gasteiz / Vitoria, Spain

Ortega F.B.,Karolinska Institutet | Ortega F.B.,University of Granada | Ruiz J.R.,Karolinska Institutet | Alkorta M.P.,Hospital of Santiago Apostol | And 5 more authors.
Journal of the American College of Nutrition | Year: 2011

Objective: The objective of this study was to examine the association of birth weight (BW) with body composition, resting metabolic rate (RMR), nonprotein respiratory quotient (NPRQ), and insulin sensitivity changes after a 12-week diet intervention program. Methods: A total of 78 obese (body mass index [BMI] 34.0 ± 2.8) women aged 36.7 ± 7 years volunteered to participate in a 12-week diet intervention program. We assessed body fat mass (FM), lean mass (LM), and bone mass (BM; measured by dual energy x-ray absorptiometry), RMR (measured by indirect calorimetry), fasting plasma glucose, and insulin before and after the intervention. We calculated BMI, FM to LM ratio (FM/ LM), and HOMA-IR. BW and gestational age were self-reported, and the BW Z-score was calculated. Results: At baseline, the BW Z-score was positively associated with LM (p< 0.01) and RMR (p< 0.05). The BW Z-score was significantly associated with diet-induced FM (p< 0.05) and FM/LM ratio changes (p< 0.01) independently of potential confounders including weight loss. The BW Z-score was not associated with diet-induced RMR or insulin resistance changes. Conclusions: Lower birth weight is associated with lower LM and RMR in obese women and could program a lower FM loss achievement after an energy-restriction diet intervention. Source

Ruiz J.R.,University of Granada | Ruiz J.R.,Karolinska Institutet | Ortega F.B.,Karolinska Institutet | Ortega F.B.,University of Granada | And 4 more authors.
PLoS ONE | Year: 2011

Background: We investigated the validity of REE predictive equations before and after 12-week energy-restricted diet intervention in Spanish obese (30 kg/m 2>BMI<40 kg/m 2) women. Methods: We measured REE (indirect calorimetry), body weight, height, and fat mass (FM) and fat free mass (FFM, dual X-ray absorptiometry) in 86 obese Caucasian premenopausal women aged 36.7±7.2 y, before and after (n = 78 women) the intervention. We investigated the accuracy of ten REE predictive equations using weight, height, age, FFM and FM. Results: At baseline, the most accurate equation was the Mifflin et al. (Am J Clin Nutr 1990; 51: 241-247) when using weight (bias:-0.2%, P = 0.982), 74% of accurate predictions. This level of accuracy was not reached after the diet intervention (24% accurate prediction). After the intervention, the lowest bias was found with the Owen et al. (Am J Clin Nutr 1986; 44: 1-19) equation when using weight (bias:-1.7%, P = 0.044), 81% accurate prediction, yet it provided 53% accurate predictions at baseline. Conclusions: There is a wide variation in the accuracy of REE predictive equations before and after weight loss in non-morbid obese women. The results acquire especial relevance in the context of the challenging weight regain phenomenon for the overweight/obese population. Source

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