Although the ‘Low-Fat’ diet was the predominant public health recommendation for weight loss and weight control for the past several decades, the obesity epidemic continued to grow during this time period. An alternative ‘low-carbohydrate’ (Low-Carb) approach, although originally dismissed and even vilified, was comparatively tested in a series of studies over the past decade, and has been found in general to be as effective, if not more, as the Low-Fat approach for weight loss and for several related metabolic health measures. From a glass half full perspective, this suggests that there is more than one choice for a dietary approach to lose weight, and that Low-Fat and Low-Carb diets may be equally effective. From a glass half empty perspective, the average amount of weight lost on either of these two dietary approaches under the conditions studied, particularly when followed beyond 1 year, has been modest at best and negligible at worst, suggesting that the two approaches may be equally ineffective. One could resign themselves at this point to focusing on calories and energy intake restriction, regardless of macronutrient distributions. However, before throwing out the half-glass of water, it is worthwhile to consider that focusing on average results may mask important subgroup successes and failures. In all weight-loss studies, without exception, the range of individual differences in weight change within any particular diet groups is orders of magnitude greater than the average group differences between diet groups. Several studies have now reported that adults with greater insulin resistance are more successful with weight loss on a lower-carbohydrate diet compared with a lower-fat diet, whereas adults with greater insulin sensitivity are equally or more successful with weight loss on a lower-fat diet compared with a lower-carbohydrate diet. Other preliminary findings suggest that there may be some promise with matching individuals with certain genotypes to one type of diet over another for increasing weight-loss success. Future research to address the macronutrient intake component of the obesity epidemic should build on these recent insights and be directed toward effectively classifying individuals who can be differentially matched to alternate types of weight-loss diets that maximize weight-loss and weight-control success.

尽管在过去的几十年中，“低脂”饮食是减肥和控制体重的主要公共卫生建议，但肥胖流行在此期间继续增长。另一种“低碳水化合物”（Low-Carb）方法虽然最初被驳回甚至被诋毁，但在过去十年的一系列研究中经过了比较测试，并且发现总体上与以下方法一样有效，甚至更多用于减肥的低脂方法和一些相关的代谢健康措施。从半满杯的角度来看，这表明减肥的饮食方法不止一种选择，而且低脂肪和低碳水化合物饮食可能同样有效。从玻璃半空的角度来看，在所研究的条件下，这两种饮食方法中的任何一种的平均体重减轻量，特别是在超过 1 年的情况下，充其量是适度的，在最坏的情况下可以忽略不计，这表明这两种方法可能同样无效。在这一点上，人们可以放弃关注卡路里和能量摄入限制，而不管常量营养素的分布如何。然而，在扔掉半杯水之前，值得考虑的是，关注平均结果可能会掩盖重要的子组成功和失败。在所有减肥研究中，无一例外，任何特定饮食组内体重变化的个体差异范围都比饮食组之间的平均组差异大几个数量级。现在有几项研究报告说，与低脂肪饮食相比，胰岛素抵抗更大的成年人在低碳水化合物饮食中减肥更成功，而胰岛素敏感性更高的成年人在低脂肪饮食中减肥同样或更成功与低碳水化合物饮食相比。其他初步研究结果表明，将具有某些基因型的个体与一种饮食而不是另一种饮食相匹配，可能会有一些希望，以提高减肥成功率。未来解决肥胖流行病中常量营养素摄入部分的研究应建立在这些最新见解的基础上，并旨在有效地对可以与替代类型的减肥饮食进行差异匹配的个体进行分类，从而最大限度地减轻体重和控制体重。