A randomized trial of a low-carbohydrate diet vs Orlistat plus a low-fat diet for weight loss.

Study Number: 36

Year: 2010

Study Citation: A randomized trial of a low-carbohydrate diet vs Orlistat plus a low-fat diet for weight loss. WS Yancy, EC Westman, JR McDuffie et al. Archives of Internal Medicine Jan 25 2010;170(2):136-145.

Link to Study: View Study

Country: US

Study Design(COUNTRY 1=RCT 2= Systematic Review 3=Non-randomized controlled 4= single arm 5= post hoc analysis 6=Non-systematic review 7. Network meta-analysis 8=other 9 follow up to study): 1

Study background and AIM: Compares effects of low-carb ketogenic (LCK) diet vs. low-fat (LF) plus Orlistat supplement diet on body weight, SBP, DBP, lipids, and glycemic control in adults with T2D.

Enrolled: 146

Completed: 122

Carb %: 15%

Carb/day: 62

Study Duration: 48 weeks

6 Months or longer: Y

Subjects: "Enrolled: 146 overweight or obese adults Completed: 122 (83.6%). Mean age: ~54 Mean BMI: ~39.4. % male: ~75% T2D: ~32%. % white: ~44%, % black: 54%"

Number of subjects and analysis: 122

Intervention: Both diet groups attended small group meetings every 2 weeks for 24 weeks, then every 4 weeks for 24 weeks. They were advised to exercise on their own for 30min/d at least 3 x week.

Did Either Arm Restrict: Y

Low-carb diet arm: "Targets E: none Carb: <20g/d Protein: none Fat: none Limits on cheese and some types veg's. Advised to increase ~5carbg/d as goal weight neared or to cope with cravings, at level to maintain weight or diminish cravings Intake E 1698kcal/d Carb: 62g/d; 14.6%E Protein: 112.2g/d; 26.4%E Fat: 106.7g/d; 56.6%E"

Carb In Low-carb Arm As %: "Target: NS Intake: 14.6%"

Fat In Low-carb Arm As %: "Target: none Intake: 56.6%"

Comparison diet ARM(S): "Low-fat plus Orlistat supplement (120mg, 3/d) Targets E: individualized, less 500-1000kcal for maintenance Carb: NR Protein: NR Fat: <30%E; saturated fat <10%E, cholesterol <300 mg/d Intake: E: ~1566kcal/d Carb: 186g/d Protein: 78g/dg/d Fat: 56.6g/d"

Outcomes Studied: Primary: weight, SBP, DBP, lipids, and glycemic control.

Result Summary: Results similar except LC diet was more effective in lowering blood pressure

FBG, Other Glucose Measures: "WG: NR BG: N BG NSS "

FBG WG Sign: *

FBG BG Sign: 0

HbA1c: "WG: NR BG: N BG NSS"

HbA1c WG Sign: *

HbA1c BG Sign: 0

Total C: "WG: NR BG: N BG NSS"

Total C WG Sign: *

Total C BG: 0

HDL-C: "WG: NR BG: N BG NSS "

HDL-C WG Sig: *

HDL-C BG Sig: 0

LDL-C: "WG: NR BG: N BG NSS"

LDL-C WG Sig: *

LDL-C BG Sig: 0

TG: "WG: NR BG: N BG NSS"

TG WG Sig: *

TG BG Sig: 0

TG/HDL-C ratio WG Sig: *

TG/HDL-C ratio BG Sig: *

Weight/bmi, Body Composition: "WG: NR BG: N BG NSS "

Weight/BMI WG Sig: *

Weight/BMI BG Sig: 0

SBP: "WG: NR BG: Y At 48 weeks LC: -5.95mmHg LF: +1.50 p<0.001"

SBP WG Sig: *

SBP BG Sig: 1

DBP: "WG: NR BG: Y At 48 weeks LC: -4.53mmHg LF: +.43 p<0.001 "

DBP WG Sig: *

DBP BG Sig: 1

Fasting Insulin: "WG: NR BG: N BG NSS "

Fasting Insulin WG SS: *

Fasting Insulin BG SS: 0

Insulin Sensitivity/Resistance: NR

Insulin Receptor Improvement WG sig: *

Insulin Receptor Improvement BG sig: *

Inflammation: "WG: NR BG: N BG NSS "

CRP WG sig: *

CRP BG sig: 0

Diabetes Medication Use: "Low-carb diet 16 patients: 1 (6%) increased dose 13 (81%) decreased dose Low-fat diet 22 patients 1 (5%) increased dose 15 (68%) decreased dose"

Safety Adverse Events: "More common in low-carb group: constipation, increased urinary frequency, halitosis, leg muscle cramps. More common in low-fat group: flatus, bowel incontinence, diarrhea. One subject with T2D in the LCK group developed worse proteinuria. serious adverse events that may have been related to the intervention: 1 LCK subject was hospitalized for syncope attributed to excessive anti-hypertension medication and 2 LF subjects were hospitalized for unstable angina. "

Retention and Compliance: "Compared with other trials, adherence was high over the 48 weeks. For example, the mean carbohydrate intake was 62g/d [15%E] at week 48 in the LC group."

Other: "Creatinine: unchanged from baseline for the two diets. Serum urea nitrogen: higher at all 4 time points with the test diet; at 48 weeks - +3.19 vs +1.23. SS p=.01. Total C; HDL ratio: The control diet performed slightly better than test diet but BG NSS. TG:HDL ratio: Test diet performed better but BG NSS."

Study Author's Conclusions: "A LCK diet led to similar improvements as the LF diet for weight loss, lipid profile, and glycemic control, but was more effective in lowering both systolic and diastolic blood pressure."

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

A randomized trial of a low-carbohydrate diet vs Orlistat plus a low-fat diet for weight loss.

Abbreviations:

Number of People in Studies:

Duration of Trial

# of Trials

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