Computational modeling of human metabolism, body weight and composition

我们继续开发人体新陈代谢和体重动态的数学模型。我们已经扩展了我们的儿童生长模型，以模拟从出生到成年的正常发育以及儿童肥胖的发展。这一模型也被用于更好地理解营养不良导致的生长停滞。 我们使用成人常量营养素代谢模型成功预测了一项临床研究的结果，该研究涉及肥胖成人对选择性限制饮食碳水化合物与脂肪的代谢反应。当模拟较长时间内可能发生的情况时，该模型预测，随着碳水化合物与脂肪的比例变化很大，体脂减少的差异相对较小。这些结果表明，当饮食中含有相同数量的卡路里时，身体最终可能会最大限度地减少体脂损失的差异。 我们验证了我们的数学方法可以通过简单地跟踪人们的体重来准确测量卡路里摄入量的变化。该方法使用140名男性和女性的数据进行了验证，这些男性和女性接受了为期两年的热量限制干预。我们使用重复剂量的双标记水（DLW）和双能X射线吸收测定法（DXA）扫描，计算了参与者在整个干预过程中摄入的卡路里数量的变化，这些昂贵的实验室技术尚未广泛使用。仅使用每个人的年龄，身高和性别，以及在两年研究中收集的体重测量结果，我们表明，平均而言，模型计算的每日卡路里消耗量的变化在DLW和DXA方法的40卡路里范围内。

We continue to develop mathematical models of human metabolism and body weight dynamics. We have extended our model of childhood growth to simulate normal development from birth through adulthood as well as the development of childhood obesity. This model is also being applied to better understand growth faltering with malnutrition. We used our model of adult macronutrient metabolism to successfully predict the results of a clinical research study involving the metabolic responses to selective restriction of dietary carbohydrates versus fat in adults with obesity. When simulating what might happen over longer periods, the model predicted relatively small differences in body fat loss with widely varying ratios of carbs to fat. Those results suggest the body may eventually minimize differences in body fat loss when diets have the same number of calories. We validated that our mathematical method provides accurate measurements of calorie intake changes by simply tracking peoples weight. The method was validated using data from 140 men and women who underwent a two-year calorie-restriction intervention. We calculated changes in the number of calories the participants ate throughout the intervention using repeated doses of doubly-labeled water (DLW) and dual energy x-ray absorptiometry (DXA) scans, expensive laboratory techniques not widely available. Using only each persons age, height and sex, and weight measurements gathered throughout the two-year study, we showed that, on average, the model-calculated changes in daily calorie consumption were within 40 calories of the DLW and DXA methods.