Less fat or fewer carbohydrates—which really causes weight loss?

Aim of the study: The rise in obesity has emphasised a focus on lifestyle and dietary habits. We aimed to address the debate between low-carbohydrate and low-fat diets and compare their effects on body weight, low-density lipoprotein cholesterol (LDL), high-density lipoprotein cholesterol (HDL), total cholesterol, and triglycerides in an adult population.

Results: This meta-analysis of 38 studies assessed a total of 6499 adults. At 6-12 months, pooled analyses of mean differences of low-carbohydrate vs. low-fat diets favoured the low-carbohydrate diet for average weight change (mean difference -1.30 kg; 95% CI -2.02 to -0.57), HDL (0.05 mmol/L; 95% CI 0.03 to 0.08), and triglycerides (TG) (-0.10 mmol/L; -0.16 to -0.04), and favoured the low-fat diet for LDL (0.07 mmol/L; 95% CI 0.02 to 0.12) and total cholesterol (0.10 mmol/L; 95% CI 0.02 to 0.18). Conclusion and Relevance: This meta-analysis suggests that low-carbohydrate diets are effective at improving weight loss, HDL and TG lipid profiles. However, this must be balanced with potential consequences of raised LDL and total cholesterol in the long-term.

Aim of the study: Low-carbohydrate diets are popular for weight loss, but their cardiovascular effects have not been well-studied, particularly in diverse populations. To examine the effects of a low-carbohydrate diet compared with a low-fat diet on body weight and cardiovascular risk factors.

Results: Sixty participants (82%) in the low-fat group and 59 (79%) in the low-carbohydrate group completed the intervention. At 12 months, participants on the low-carbohydrate diet had greater decreases in weight (mean difference in change, -3.5 kg [95% CI, -5.6 to -1.4 kg]; P = 0.002), fat mass (mean difference in change, -1.5% [CI, -2.6% to -0.4%]; P = 0.011), ratio of total-high-density lipoprotein (HDL) cholesterol (mean difference in change, -0.44 [CI, -0.71 to -0.16]; P = 0.002), and triglyceride level (mean difference in change, -0.16 mmol/L [-14.1 mg/dL] [CI, -0.31 to -0.01 mmol/L {-27.4 to -0.8 mg/dL}]; P = 0.038) and greater increases in HDL cholesterol level (mean difference in change, 0.18 mmol/L [7.0 mg/dL] [CI, 0.08 to 0.28 mmol/L {3.0 to 11.0 mg/dL}]; P < 0.001) than those on the low-fat diet. The low-carbohydrate diet was more effective for weight loss and cardiovascular risk factor reduction than the low-fat diet.

Aim of the study: Trials comparing the effectiveness and safety of weight-loss diets are frequently limited by short follow-up times and high dropout rates.

Results: The rate of adherence to a study diet was 95.4% at 1 year and 84.6% at 2 years. The Mediterranean-diet group consumed the largest amounts of dietary fiber and had the highest ratio of monounsaturated to saturated fat (P<0.05 for all comparisons among treatment groups). The low-carbohydrate group consumed the smallest amount of carbohydrates and the largest amounts of fat, protein, and cholesterol and had the highest percentage of participants with detectable urinary ketones (P<0.05 for all comparisons among treatment groups). The mean weight loss was 2.9 kg for the low-fat group, 4.4 kg for the Mediterranean-diet group, and 4.7 kg for the low-carbohydrate group (P<0.001 for the interaction between diet group and time); among the 272 participants who completed the intervention, the mean weight losses were 3.3 kg, 4.6 kg, and 5.5 kg, respectively.

Aim of the study: The role of very-low-carbohydrate ketogenic diets (VLCKD) in the long-term management of obesity is not well established. The present meta-analysis aimed to investigate whether individuals assigned to a VLCKD (i.e.

Results: A total of thirteen studies met the inclusion/exclusion criteria. In the overall analysis,five outcomes revealed significant results. Individuals assigned to a VLCKD showed decreased body weight (weighted mean difference -0·91 (95% CI -1·65, -0·17) kg, 1415 patients), TAG (weighted mean difference -0·18 (95% CI -0·27, -0·08) mmol/l, 1258 patients)and diastolic blood pressure (weighted mean difference -1·43 (95% CI -2·49, -0·37) mmHg, 1298 patients) while increased HDL-C(weighted mean difference 0·09 (95% CI 0·06, 0·12) mmol/l, 1257 patients) and LDL-C (weighted mean difference 0·12 (95% CI 0·04,0·2) mmol/l, 1255 patients). Individuals assigned to a VLCKD achieve a greater weight loss than those assigned to a LFD in the longterm; hence, a VLCKD may be an alternative tool against obesity.

Aim of the study: Low-carbohydrate diets (LCDs) have been suggested as a potential treatment option for females with lipedema, due to their superiority in reducing pain, possibly through improvements in insulin dynamics. The objective of this secondary analysis was to compare changes in markers of glucose and insulin dynamics after a low-carbohydrate versus low-fat low-energy diets in females with lipedema and obesity.

Results: A total of 70 females (35 in each group, age 47 ± 11 years, BMI 37 ± 5 kg/m2) were included in the analysis. Both groups lost body weight, but with a significantly greater weight loss in the LCD group. Both groups showed ed a reduction in basal glucose, C-peptide, and insulin concentrations, with a greater reduction in glucose on the LCD. A significant increase in glucose iAUC, C-peptide iAUC, insulin clearance, and Matsuda index was observed in the LCD group only. Both groups experienced an increase in GIP tAUC, as well as a reduction in HOMA-IR, with no significant differences between groups. No associations were seen between changes in glucose and insulin measures and changes in pain. Both diets improved insulin dynamics in females with lipedema and obesity, despite additional benefits in the LCD group.

Aim of the study: It remains unclear if a low-carbohydrate, high-fat (LCHF) diet is a possible treatment strategy for type 2 diabetes mellitus (T2DM), and the effect on nonalcoholic fatty liver disease (NAFLD) has not been investigated. To investigate the effect of a calorie-unrestricted LCHF diet, with no intention of weight loss, on T2DM and NAFLD compared with a high-carbohydrate, low-fat (HCLF) diet.

Results: The mean age was 56 years (SD, 10), and 58% were women. Compared with the HCLF diet, participants on the LCHF diet had greater improvements in hemoglobin A1c (mean difference in change, -6.1 mmol/mol [95% CI, -9.2 to -3.0 mmol/mol] or -0.59% [CI, -0.87% to -0.30%]) and lost more weight (mean difference in change, -3.8 kg [CI, -6.2 to -1.4 kg]). Both groups had higher high-density lipoprotein cholesterol and lower triglycerides at 6 months. Changes in low-density lipoprotein cholesterol were less favorable in the LCHF diet group than in the HCLF diet group (mean difference in change, 0.37 mmol/L [CI, 0.17 to 0.58 mmol/L] or 14.3 mg/dL [CI, 6.6 to 22.4 mg/dL]). No statistically significant between-group changes were detected in the assessment of NAFLD. Changes were not sustained at the 9-month follow-up.

Aim of the study: The aim of this study was to determine whether a walnut-based low carbohydrate diet (w-LCD) promotes fat redistribution and reduces visceral fat accumulation in people with central obesity (CO).

Results: The Group × Time interaction effects were significant for TLR (η² = 0.071, p = 0.039) and VFA (η² = 0.093, p = 0.014) with moderate effect, and body mass index (BMI, η² = 0.168, p = 0.001) with large effect. Although comparison be-tween groups revealed no significant on TLR, VFA and BMI at 12 weeks, comparison within groups showed all decreased with large effect on TLR (η² = 0.174, p = 0.001), VFA (η² = 0.393, p <0.001) and BMI (η² = 0.399, p <0.001) in the w-LCD group over time. A w-LCD achieves a significantly greater and faster fat reduction over time compared to the control group, providing a solid evidence-based foundation for dietary management in people with CO.