Effects of a Low‐intensity Intervention That Prescribed a Low‐carbohydrate vs. a Low‐fat Diet in Obese, Diabetic Participants

Abstract

Low‐carbohydrate diets have been associated with significant reductions in weight and HbA1c in obese, diabetic participants who received high‐intensity lifestyle modification for 6 or 12 months. This investigation sought to determine whether comparable results to those of short‐term, intensive interventions could be achieved over a 24‐month study period using a low‐intensity intervention that approximates what is feasible in outpatient practice. A total of 144 obese, diabetic participants were randomly assigned to a low‐carbohydrate diet (<30 g/day) or to a low fat diet (≤30% of calories from fat with a deficit of 500 kcal/day). Participants were provided weekly group nutrition education sessions for the first month, and monthly sessions thereafter through the end of 24 months. Weight, HbA1c, glucose, and lipids were measured at baseline and 6, 12, and 24 months. Of the 144 enrolled participants, 68 returned for the month 24 assessment visit. Weights were retrieved from electronic medical records for an additional 57 participants (total, 125 participants) at month 24. All participants with a baseline measurement and at least one of the three other measurements were included in the mixed‐model analyses (n = 138). The low‐intensity intervention resulted in modest weight loss in both groups at month 24. At this time, participants in the low‐carbohydrate group lost 1.5 kg, compared to 0.2 kg in the low‐fat group (P = 0.147). Lipids, glycemic indexes, and dietary intake did not differ between groups at month 24 (or at months 6 or 12) (ClinicalTrials.gov number, NCT00108459).

A critical review of low‐carbohydrate diets in people with Type 2 diabetes

“…Davis et al [7] did not aim for a specific carbohydrate intake in grams, but because the carbohydrate intake was based on the Atkins diet, it is reasonable to assume that it was not in excess of a typical Atkins diet, which is~47 g [14]. In Iqbal et al [11], the lowest mean carbohydrate intake was 154 g at 26 weeks, which is a far cry from the aim of < 30 g. In addition, the carbohydrate intake increased as the duration of the study increased. The final carbohydrate intake at 104 weeks was 188 g. In the study by Westman et al [12], mean carbohydrate intake was 49 g at 24 weeks, which is lower than that of Iqbal et al [11], but is more than double the target of 20 g. In the study by Davis et al [7], the actual intake at 13 weeks was 77 g, but this increased to 137 and 132 g at 26 and 52 weeks, respectively.…”

“…Studies prescribed a carbohydrate intake in grams or carbohydrate as a % of TEI, with the majority, other than Iqbal et al [11], Westman et al [12] and Davis et al [7], using the latter approach. The limitation of the % of TEI approach in assessing carbohydrate intake was seen in the study by Krebs et al [13] in which there was a significantly greater reduction in carbohydrate intake in the LCD when reflected as % of TEI (P < 0.0001), whereas when assessed in grams of carbohydrates, the difference was not statistically This review provides new insights into the effectiveness of low-carbohydrate diets by demonstrating that limiting inclusion in meta-analyses to higher quality studies results in more coherent and consistent outcomes.…”

“…As seen in Table 4, people often deviated from their prescribed carbohydrate intake. Iqbal et al [11] and Westman et al [12] aimed for a carbohydrate intake of < 30 and < 20 g, respectively. Davis et al [7] did not aim for a specific carbohydrate intake in grams, but because the carbohydrate intake was based on the Atkins diet, it is reasonable to assume that it was not in excess of a typical Atkins diet, which is~47 g [14].…”

Dietas bajas en hidratos de carbono para diabéticos de tipo 2. Revisión sistemática

“…(17) (15) puede observarse una reducción significativa en el grupo DBCH con respecto a los valores iniciales (p = 0,049). En algunos estudios se encuentra una gran reducción de HbA1c en el grupo DBCH a los 6 meses y posteriormente sus niveles se van equiparando a los iniciales (22,23). Por otra parte, en el estudio de Tay y cols.…”

“…Multitud de trabajos compararon niveles de colesterol total séri-co entre grupos de intervención, y en 3 de ellos se encontró mayor reducción en el grupo DBG (20,22,23). En otros 4 se encontró mayor reducción en el grupo DBCH (14,17,19,21), y en el resto no hubo diferencias entre grupos.…”