Impact of Nutrition and Swimming Intervention in Pregnant Mice Fed Hyper-Lipidic and Hyper-Caloric Diet: Effect on Body Mass Index and Other Phenotypic Characteristics Marisol Leon1, Maria A. Miglino1, Mirel Cabrera2, Pablo Cabral2, Kimberly K. Buhman3, Christina R. Ferreira1,4 1Surgery Department, School of Veterinary Medicine and Animal Science, University of Sao Paulo, Sao Paulo, Brazil. 2Department of Radiopharmacy, Center for Nuclear Research, Universidad de la República, Montevideo, Uruguay 3Department of Nutrition Science, Purdue University, West Lafayette, Indiana, 47906, United States. 4Department of Chemistry and Center for Analytical Instrumentation Development, Purdue University, West Lafayette, IN, 47907, United States Hyper-lipidic and hyper-caloric (HL) nutrition is related to obesity and other clinical conditions referred as metabolic syndrome. We report body-mass-index (BMI) and other phenotypic aspects of mice fed HL diet before and at gestation. Animals were divided into six experimental groups: (1) HL diet before and at gestation (HL/HL), (2) Normo-lipidic (NL) diet before and at gestation (NL/NL), (3) NL before gestation and HL at gestation (NL/HL), (4) HL diet before gestation and NL diet only at gestation (HL/NL), (5) NL diet exposed to swimming at gestation (NL/NL+swim); and (6) HL diet exposed to swimming at gestation (HL/HL+swim). BMI and food intake were monitored during the whole experiment. Weight and aspects of the liver, heart, and placenta, as well was number and weight of embryos were recorded at 9.5, 13.5 and 16 days of gestation. HL/HL dams presented higher BMI, liver and heart weight compared to NL/NL counterparts. Placenta and fetal weight decreased due to HL diet. When HL diet was changed to NL diet and swimming was introduced, the BMI as well as liver and heart weight decreased, and the placenta weight increased. The introduction of HL diet only at gestation (NL/HL) rapidly a phenotype similar to NL/NL. No impact on the fertility has been observed among the groups. Changes in the NL/HL indicate the importance of NL diet at gestation. Normo-lipidic diet and swimming intervention at gestation were not enough to reverse HL diet impact, but the benefits of these interventions were observed in the measurements reported.