Low-carbohydrate diets lead to significantly greater weight loss and improvements in triglyceride and high-density lipoprotein levels in adolescents with obesity compared to low-fat diets, according to a recent meta-analysis.

Researchers examined the comparative effects of low-carbohydrate diets (LCD) versus low-fat diets (LFD) on weight loss and metabolic parameters in adolescents with overweight and obesity. The analysis included five randomized controlled trials encompassing 192 participants.

The study's results—published in Diabetes, Metabolic Syndrome and Obesity—indicated that adolescents adhering to an LCD achieved greater reductions in body weight, body mass index (BMI), and triglyceride (TG) levels compared to those following an LFD. Specifically, the LCD group exhibited a mean weight loss of 2.81 kg more than the LFD group (95% confidence interval [CI] = −5.38 to −0.25), with a corresponding decrease in BMI of 1.13 kg/m² (95% CI = −2.14 to −0.11).  Additionally, the analysis showed that TG levels were lower by an average of 0.36 mmol/L in the group following the LCD compared to the LFD, with a confidence interval ranging from 0.46 to 0.27 mmol/L. Participants in the LCD group had HDL levels that were, on average, 0.08 mmol/L higher than those in the LFD group, with the confidence interval ranging from 0.04 to 0.12 mmol/L.

No significant differences were observed between the two dietary interventions concerning Homeostasis Model Assessment of Insulin Resistance, percent body fat, total cholesterol (TC), and low-density lipoprotein (LDL) cholesterol. The study indicated that there was no significant difference in the reduction of body fat percentage between the LCD and LFD groups, with an average difference of 0.44%, and a confidence interval range of –0.94% to 1.82%. Similarly, the study found no significant difference in TC levels between the LCD and LFD groups, with an average difference of 0.12 mmol/L and a confidence interval range of –0.01 to 0.25 mmol/L. The analysis also showed no significant difference in LDL levels between those following a LCD and those on a LFD, with an average difference of 0.25 mmol/L and a confidence interval between –0.02 and 0.52 mmol/L.

These findings suggest that while both dietary approaches can facilitate weight loss, an LCD may result in greater improvements in certain lipid profiles in this population than an LFD. However, further research is required to evaluate the long-term effects of LCDs on metabolic health in this demographic. 

The authors declared no competing interests.