There are two proven dietary approaches to shift type 2 diabetes (T2D) into remission: low energy diets (LED) and low carbohydrate diets (LCD). These approaches differ in their rationale and application yet both involve carbohydrate restriction, either as an explicit goal or as a consequence of reducing overall energy intake. The aims of this systematic review were to identify, characterise and compare existing clinical trials that utilised "low carbohydrate" interventions with differing energy intakes. Electronic databases CENTRAL, CINAHL, Embase, MEDLINE and Scopus were searched to identify controlled clinical trials in adults with T2D involving low carbohydrate intake (defined as <130g carbohydrate/day) and reporting weight and glycemic outcomes. The initial database search yielded 809 results, of which 18 studies met the inclusion criteria. 12/18 studies utilised low carbohydrate diets with moderate or unrestricted energy intake. Six trials utilised low energy diets (<1200kcal/day), with all except one incorporating meal-replacements as part of a commercial weight loss programme. Interventions using both restricted and unrestricted (ad libitum) energy intakes produced clinically significant weight loss and reduction in HbA1c at study end-points. Trials that restricted energy intake were not superior to those that allowed ad libitum low carbohydrate feeding at 12 and 24 months. An association was observed across studies between average weight loss and reduction in HbA1c, which strengthened with trial length, indicating that sustained weight loss is key to T2D remission. Further research is needed to specifically ascertain the weight-independent effects of carbohydrate restriction on glycemic control in T2D.

中文翻译：

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限制碳水化合物和卡路里在2型糖尿病的治疗中：对不同能量水平的“低碳水化合物”干预措施有效性的系统评价

有两种成熟的饮食方法可将2型糖尿病（T2D）转变为缓解：低能量饮食（LED）和低碳水化合物饮食（LCD）。这些方法的原理和应用各不相同，但都涉及碳水化合物的限制，这既是明确的目标，又是减少总能量摄入的结果。该系统评价的目的是鉴定，表征和比较利用“低碳水化合物”干预措施和不同能量摄入的现有临床试验。检索了电子数据库CENTRAL，CINAHL，Embase，MEDLINE和Scopus，以鉴定在成人T2D中涉及低碳水化合物摄入（定义为每天<130g碳水化合物）并报告体重和血糖结果的对照临床试验。最初的数据库搜索产生809个结果，其中18项研究符合纳入标准。12/18研究利用低碳水化合物饮食摄入适度或不受限制的能量。六项试验使用了低能量饮食（<1200kcal /天），除一项试验外，所有试验均纳入了替代膳食作为商业减肥计划的一部分。在研究终点，使用限制和非限制（随意）能量摄入进行干预可产生临床上显着的体重减轻和HbA1c降低。限制能量摄入的试验并不优于允许在12和24个月随意进食低碳水化合物的试验。在整个研究中观察到平均体重减轻与HbA1c减少之间的关联性，该关联性随着试验时间的延长而增强，表明持续的体重减轻是T2D缓解的关键。