Plain language summary
During the past 30 years, there has been a great deal of controversy about the composition of the optimal diet for weight loss and maintenance. The aim of this study was to analyse data from the POUNDS LOST trial, to investigate whether fasting plasma glucose (FPG) and fasting insulin (FI) are prognostic markers for long-term weight loss in four diets differing in carbohydrate, fat, and protein content, and assess the role of dietary fibre intake. This study was an analysis of the original trial for which baseline FPG levels were used to stratify subjects as being normoglycemic (FPG < 100 mg/dL) or prediabetic. Six hundred thirty-nine subjects were included of which 61% were women. Results show that subjects with normoglycemia lost the most body weight when randomized to the low-fat/high-protein diet, and that subjects with insulin resistance (high HOMA-IR) lost the most on the high-fat/high-protein diet. Furthermore, participants with the highest intake of dietary fibre lost more body weight during the 24-month dietary intervention period. Authors conclude that although modest differences in diet-specific weight loss between glycaemic phenotypes were identified, these findings need to be confirmed in randomised trials with this aim as a primary end-point.
Abstract
Efforts to identify a preferable diet for weight management based on macronutrient composition have largely failed, but recent evidence suggests that satiety effects of carbohydrates may depend on the individual's insulin-mediated cellular glucose uptake. Therefore, using data from the POUNDS LOST trial, pre-treatment fasting plasma glucose (FPG), fasting insulin (FI), and homeostatic model assessment of insulin resistance (HOMA-IR) were studied as prognostic markers of long-term weight loss in four diets differing in carbohydrate, fat, and protein content, while assessing the role of dietary fiber intake. Subjects with FPG <100 mg/dL lost 2.6 (95% CI 0.9;4.4, p = 0.003) kg more on the low-fat/high-protein (n = 132) compared to the low-fat/average-protein diet (n = 136). Subjects with HOMA-IR ≥4 lost 3.6 (95% CI 0.2;7.1, p = 0.038) kg more body weight on the high-fat/high-protein (n = 35) compared to high-fat/average-protein diet (n = 33). Regardless of the randomized diet, subjects with prediabetes and FI below the median lost 5.6 kg (95% CI 0.6;10.6, p = 0.030) more when consuming ≥35 g (n = 15) compared to <35 g dietary fiber/10 MJ (n = 16). Overall, subjects with normal glycemia lost most on the low-fat/high-protein diet, subjects with high HOMA-IR lost most on the high-fat/high protein diet, and subjects with prediabetes and low FI had particular benefit from dietary fiber in the diet.
Methodological quality
Jadad score
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