Weight-reducing diets with low carbohydrates compared with weight-reducing diets with balanced carbohydrates in overweight and obese participants without T2DM (in the weight-reducing phase only). Low-carb weight-reduction diets are likely to result in little to no difference in weight change after 3 to 8.5 months. Low-carb weight-reduction diets are likely to result in little to no difference in weight change (kg) after 1 to 2 years.
Low-carbohydrate weight-reduction diets probably result in little or no change in DBP change at 1 to 2 years. Low-carb weight loss diets probably result in little or no change in weight change at 3 to 6 months. Low-carbohydrate weight-reduction diets probably result in little or no change in weight change at 1 to 2 years.
Weight-reducing diets that are low in carbohydrates are likely to result in little to no difference in change in HbA1c after 1 to 2 years. Low-carb, weight-reducing diets are likely to result in little to no difference in change in LDL cholesterol after 1 to 2 years.
Trials in participants without T2DM: weight reduction phase alone (comparison 1) and weight reduction phase followed by a weight maintenance phase (comparison 2). Results for only the active weight reduction phases of the diets in participants without T2DM were reported in comparison 1. The control diets in most trials in participants without T2DM were balanced for carbohydrate, fat and protein (n = 38) (Table 2) .
Trials in participants with T2DM: weight loss phase alone (comparison 3) and weight loss phase followed by weight maintenance phase (comparison 4). The control diets in most trials in participants with T2DM were balanced for carbohydrate, fat and protein (n = 13) (Table 3). Funding sources were not reported in two trials in participants without T2DM (Aude 2004; Landers 2002).
The overall risk of bias across trials in participants without T2DM was similar and mostly high. Across trials in participants with T2DM, the overall risk of bias of the results was similar and mostly high.
Low-carbohydrate weight-reducing diets versus balanced-carbohydrate weight-reducing diets in overweight
The GRADE assessment suggests that weight-reduction diets containing low carbohydrates are likely to result in little to no difference in body weight change over one to two years compared to weight-reduction diets containing balanced carbohydrates in overweight and obese participants without T2DM (evidence with moderate certainty, once downgraded due to risk of bias). The meta-analysis of the average difference in weight reduction between low-carb and high-carb diets showed little to no difference. The GRADE assessment suggests that weight-reducing, low-carbohydrate diets are likely to result in little to no difference in change in DBP compared to weight-reducing, balanced-carbohydrate diets over a period of one to two years in overweight and obese participants without T2DM (moderate-certainty evidence , downgraded once due to risk of bias).
Mean change in SBP from baseline in the 11 trials reporting this outcome ranged from reductions of 13.8 mmHg to 0.2 mmHg in the low-carbohydrate diet groups and from a reduction of 14.6 mmHg to an increase of 1.7 mmHg in balanced carbohydrate diet groups over one to two years of follow-up. GRADE assessment suggests that low-carbohydrate weight-reduction diets are likely to result in little or no difference in change in LDL-cholesterol over one to two years compared with balanced-carbohydrate weight-reduction diets in overweight and obese participants without T2DM (moderately certain evidence, downgraded once for risk of bias). Over one to two years, the mean change in LDL cholesterol from baseline across the 13 trials reporting this outcome ranged from a reduction of 0.3 mmol/L to an increase of 0.6 mmol/L with diets low in carbohydrate content and from a reduction of 0.31 mmol/L L to an increase of 0.1 mmol/L with a balanced carbohydrate diet.
Over one to two years, the mean change in total cholesterol from baseline ranged from a reduction of 0.4 mmol/L to an increase of 0.7 mmol/L with low-carbohydrate diets and from a reduction of 0.42 mmol/L /L in an increase of 0.13 mmol. /L with carbohydrate-balanced diets in the 11 trials that reported this. In the 13 trials that reported on triglycerides over one to two years, the mean change from baseline ranged from reductions of 0.58 mmol/L to 0.1 mmol/L with low-carbohydrate diets and a reduction of 0.44 mmol/L /L in an increase of 0.02 mmol/L with carbohydrate-balanced diets.
Low-carbohydrate weight-reducing diets versus balanced-carbohydrate weight-reducing diets in overweight
The GRADE rating indicates that the evidence is very uncertain about whether there is a difference in the number of participants per group with constipation at three to six months when comparing low-carbohydrate weight loss diets. The GRADE rating indicates that the evidence is very uncertain about the effect of low-carbohydrate weight-loss diets that include a weight-maintenance phase compared with balanced-carbohydrate weight-loss diets that include a weight-maintenance phase on change in DBP after one year in overweight and obese participants without T2DM (very low-certainty evidence, downgraded once for risk of bias and twice for imprecision). The study reported a mean DBP reduction from baseline of 4 mmHg in the low-carbohydrate group and 6 mmHg in the balanced-carbohydrate diet group.
For SBP, the study reported a mean decrease from baseline of 2 mmHg in the low-carb group and an increase of 2 mmHg in the balanced-carb group. The GRADE rating suggests that the evidence is very uncertain about the effect of low-carbohydrate weight-reduction diets that include a weight-maintenance phase compared with balanced-carbohydrate weight-reduction diets that include a weight-maintenance phase on change in LDL over one to two years in overweight and obese participants without T2DM (very low-certainty evidence, reduced once for risk of bias and twice for imprecision). Mean reductions in LDL cholesterol from baseline ranged from 0.79 mmol/L to 0.2 mmol/L with low-carbohydrate diets and from 1.15 mmol/L to 0.14 mmol/L with balanced-carbohydrate diets.
L to an increase of 0.11 mmol/L on low-carbohydrate diets and from increases of 0.03 mmol/L to 0.04 mmol/L on balanced-carbohydrate diets. Mean reductions in total cholesterol ranged from 0.24 mmol/L to 0.79 mmol/L on the low-carbohydrate diets and from 0.17 mmol/L to 1.14 mmol/L on the balanced-carbohydrate diets.
Low-carbohydrate weight-reducing diets versus balanced-carbohydrate weight-reducing diets in overweight
The GRADE assessment suggests that low-carbohydrate weight-reduction diets are likely to produce little or no difference in weight change over one to two years compared with balanced-carbohydrate weight-reduction diets in overweight and obese participants with T2DM (moderate-certainty evidence, downgraded once for risk of bias). The mean weight loss from baseline over one to two years in the seven trials that reported this outcome was 8.9 kg to 2 kg on low-carbohydrate weight-loss diets and 7.4 kg to 1.7 kg on weight loss diets with balanced carbohydrates. The GRADE assessment suggests that low-carbohydrate weight-reduction diets are likely to produce little or no difference in DBP change compared with balanced carbohydrate-balanced weight-reduction diets over one to two years in overweight and obese participants with T2DM (moderate-certainty evidence, downgraded once due to risk of bias).
GRADE assessment suggests that low-carbohydrate weight-reduction diets are likely to result in little or no difference in change in HbA1c compared with balanced-carbohydrate weight-reduction diets over one to two years in overweight and obese participants with T2DM (moderate-certainty evidence, downgraded one times the risk of bias). The mean change in HbA1c from baseline over one to two years ranged from a 2% reduction to a 0.1% increase with low-carbohydrate diets and from a 1.8% reduction to a 0.2% increase with balanced carbohydrate diets across the six. trials that reported this result. The meta-analysis of the mean difference in change in HbA1c between low-carbohydrate and balanced-carbohydrate diets showed little or no difference after one to two years (MD CI -0.38 to 0.10, I participants, 6 RCT' is, moderately certain evidence Analysis 3.13).
GRADE assessment suggests that low-carbohydrate weight-reduction diets are likely to result in little to no difference in change in LDL cholesterol over one to two years compared with balanced-carbohydrate weight-reduction diets in overweight and obese participants with T2DM (moderate-certainty evidence , downgraded once for risk of bias). Mean change from baseline over one to two years across the seven trials that reported on change in total cholesterol ranged from a reduction of 0.88 mmol/L to an increase of 0.2 mmol/L with low-carbohydrate diets and of reductions from 0.96 mmol/L to 0.1 mmol/L with balanced carbohydrate diets.
Low-carbohydrate weight-reducing diets versus balanced-carbohydrate weight-reducing diets in overweight
