EXERCISE AND DIET EFFECTS ON LACTATION PERFORMANCE

许多美国女性希望在产后期间减肥 并经常转向热量限制或运动来帮助实现这一目标 目标.然而，能量平衡能被改变到什么程度还不清楚。 在哺乳期受到影响之前。拟议研究的目标是 评估短期热量限制或运动的效果， 热量限制对泌乳性能的影响。 那些只在 产后8-12周母乳喂养将被随机分配到3个 组（N=25/组）持续11天：a）对照，给予100%能量 需要; B）热量限制到能量需求的65%;和c）运动加 热量限制以产生与B组相似的热量不足。 基线能量摄入和支出的测量将用于 确定最初的能量需求，并将作为饮食的基础 在干预期间规定的家具和运动水平。 数据 乳汁量和成分，血浆催乳素，母体成分 在11天之前和期间收集婴儿体重 干预期。牛奶体积将通过三维测试称重来确定 使用电子天平。母乳样本将由替代者采集 24小时内的乳房挤压，并分析脂肪、乳糖、蛋白质、能量 和脂肪酸浓度。将测定血浆催乳素水平 通过留置导管采集血样，采用放射免疫分析法 在哺乳期之前、期间和之后。 母体 组成将通过流体静力学称重和氘分析来评估。 在呼吸水中稀释。重复测量方差分析将 用于检查干预的影响。 的结果 这项研究将有助于确定一个安全的最低热量摄入， 美国女性的哺乳期

Many women in the U.S. desire to lose weight during the postpartum period and often turn to caloric restriction or exercise to help accomplish this goal. However, it is unknown to what extent energy balance can be altered before lactation is compromised. The goal of the proposed research is to evaluate the effect of short-term caloric restriction or exercise with caloric restriction on lactation performance. Women who are exclusively breastfeeding at 8-12 wk postpartum will be randomly assigned to one of 3 groups (N=25/group) for a period of 11 d: a) control, given 100% of energy needs; b) caloric restriction to 65% of energy needs; and c) exercise plus caloric restriction to create a similar caloric deficit as in group b. Measurements of baseline energy intake and expenditure will be used to determine initial energy needs and will serve as the basis for the diets furnished and exercise levels prescribed during the intervention. Data on milk volume and composition, plasma prolactin, maternal body composition and infant weight will be collected prior to and during the 11-d intervention period. Milk volume will be determined by 3-d test-weighing using an electronic balance. Milk samples will be collected by alternate breast expression over 24 h and analyzed for fat, lactose, protein, energy and fatty acid concentrations. Plasma prolactin levels will be determined by radioimmunoassay from blood samples collected by indwelling catheter before, during and after a breastfeeding episode. Maternal body composition will be assessed by hydrostatic weighing and deuterium dilution in respiratory water. Repeated measures analysis of variance will be used to examine the impact of the intervention. The results of this study will be useful for determining a safe minimal caloric intake during lactation for U.S. women.