To test the hypothesis that a carb-restricted diet can simultaneously improve the cluster of markers for metabolic syndrome, which can be understood as a carbohydrate-sensitive mechanism.
27
2009
1
"To test the hypothesis that a carb-restricted diet can simultaneously improve the cluster of markers for metabolic syndrome, which can be understood as a carbohydrate-sensitive mechanism. To investigate the impacts of a low-carb diet on metabolic syndrome, compared to a LF diet."
N
40
"Aim of diet was to induce a low level of ketosis Targets E: ~1500kcal/d Carb: 12%E Protein: 28%E Fat: 59%E Intake E: 1504kcal/d Carb: 44.8g/d, 12.4%E Protein: 104.8g/d; 28.1%E Fat: 100.2g/d, 58.9%E (36.4g/d saturated fat)"
"Lowfat diet Subjects instructed on foods allowed and to avoid. Targets E: ~1500kcal/d Carb: ~55%E Protein: ~20%E Fat: ~24%E (10%E from saturated fat; <300mg cholestrol/d). Intake E: 1478kcal/d Carb: 208.3g/d, 55.8%E Protein: 71.5g/d; 19.6%E Fat: 40.0g/d, 23.8%E (11.7g/d saturated fat)"
"Primary: markers of metabolic syndrome - lipid levels, HDL:total C ratio, fasting insulin, FBG, insulin area under the curve (AUC); weight, BMI and body composition, insulin sensitivity. Secondary: markers of CVD risk - postprandial lipemia, Apob:ApoA ratio, LDL particle distribution, serum retinol binding protein 4 (linked to insulin-resistant states)."
"Fasting glucose WG: NR BG: Y Baseline→12 weeks LC diet 101mg/dL→89 LF diet 96mg/dL→94 BG SS p=0.006"
*
1
NR
*
*
"WG: NR BG: N BG NSS"
*
0
"WG: NR BG: Y Baseline→12 weeks LC diet 36mg/dL→40 LF diet 39mg/dL→38 BG SS p=0"
*
1
"WG: NR BG: N BG NSS"
*
0
"WG: NR BG: Y Baseline→12 weeks TG LC diet 211mg/dL→104 (-51%) LF diet 187mg/dL→151 (-19%) BG SS p=0 TG:HDL ratio LC diet: -54% LF diet: -20% BG SS p<0.001 TG AUC After 12 weeks, the postprandial test at 6 hours after high-fat meal found the AUCs for the 2 diets, compared to baseline were: LC diet: -47% F diet: -15%"
*
1
*
*
"Weight, BMI, fat mass, abdominal fat WG: NR BG: Y Baseline→12 weeks Weight LC diet 95.5kg→86.4 (-10.5%) LF diet 94.4→89.2 (-5.8%) BG SS p=0.00 BMI LC diet 33.5→30.0 LF diet 32.1→30.3 BG SS p=0.00 Fat mass reduction was SS more with LC diet. p=0.009 SS more lean mass was lost on LC diet (6.3% vs 1.8%). p=0.009 Abdominal fat loss SS greater on LC diet. % body fat loss BG NSS."
*
1
NR
*
*
NR
*
*
"Fasting insulin & insulin AUC WG: NR BG: Y Baseline→12 weeks Fasting insulin LC diet 107pmol/L→54 LF diet 70pmol/L→57 BG SS p=0.017 "
*
1
"HOMA WG: NR BG: Y Baseline→12 weeks LC diet 2.9→1.3 LF diet 1.7→1.4 BG SS p=0.009 "
*
1
NR
*
*
NR
NR
"ApoB:ApoA-1 ratio: worsened on LF diet, improved on LC diet. BG SS p=0.001. Leptin (3 measures): On all 3, the LC diet lowered leptin to a SS greater degree than LF diet. BG SS p varied. Total saturated fat acids reduced 57% in LC diet vs 24% in LF diet. LDL particle patterns: the LC diet improved particle size (larger) and reduced the amount of small and very smal LDL particles, SS BG. "
"...a diet restricted in carblhydrate can provide a more comprehensive improvement in the clinical risk factors associated with MetS than a LF diet at reduced caloric intake. ... carbohydrate restriction has the ability to target the range of markers [for MetS] with a single intervention. That this collection of ... markers responds in concert to carbohydrate restriction provides support for considering them as a single syndrome ... Low-carbohydrate diets therefore represent an alternative strategy for general health beyond weight regulation."
Abbreviations:
AHA - American Heart Association;
ALT - alanine aminotransferase;
AMDR - acceptable macronutrient distribution range;
AST - aspartate aminotransferase;
BG - between study groups;
BHOB - beta-hydroxybutyrate;
DBP - diastolic blood pressure;
E- energy, caloric intake;
eGFR - estimated glomerular filtration rate;
FBG - fasting blood glucose;
GGT - gamma-glutamyl transferase;
HDL-C - high-density lipoprotein cholesterol;
iGFR - isotope glomerurar filtration rate;
LDL-C - low-density lipoprotein cholesterol;
NAFLD - non-alcoholic fatty liver disease;
NR - not reported (or data needed for calculation not available);
N - no;
NA - not applicable;
NS - not specified;
NSS - not statistically significant;
SBP - systolic blood pressure;
SS - statistically significant;
TG - triglyceride;
total C - total cholesterol;
V - varied, mixed;
WG - within a study group;
WMD - weighted mean difference;
Y - yes
Number of People in Studies:
3,296 Enrolled in randomized controlled trials on 25% or less carbohydrates
2,626 Completed randomized controlled trials on 25% or less carbohydrates
79.67% 82% completion of studies
Duration of Trial
<6 Months
6-9 Months
1 -2 years
>2 years
# of Trials
36
6
9s
1