Table 1.

Characteristics of 23 Randomized Controlled Clinical Trials From Multiple Countries Comparing Low-Carbohydrate Diets With Low-Fat Diets, 1966–2011

First Author, Year (Reference No.)	Country	Design	Blinding	Inclusion Criteria	Intervention or Targeted Dietary Composition		Mean Intervention Duration, months	Completion %
					LCD	LFD		LCD	LFD
Brehm, 2003 (5)	United States	Parallel	Open	Female sex; BMIa 30–35; no DM or CVD; normal BP; NP	<20 g carbohydrates/day for 1–2 weeks, then increasing to 40–60 g/day only if self-testing of urinary ketones continued to indicate ketosis	30% fat, 55% carbohydrate, 15% protein	6	85	74
Brinkworth, 2009 (22)	Australia	Parallel	Open	Abdominal obesity and ≥1 METS components; no DM or CVD; NP	4% carbohydrate, 35% protein, 61% fat (20% saturated fat), <20 g carbohydrates/day during weeks 1–8 and then <40 g/day thereafter	30% fat (8% or 10 g/day saturated fat), 46% carbohydrate, 24% protein	12	58	59
Dansinger, 2005 (8)	United States	Parallel	Open	Obesity and ≥1 METS; BMI 27–42; no CKD; NP	<20 g carbohydrates/day, increasing to 50 g/day	Vegetarian diet, 10% fat	12	52	50
Davis, 2009 (23)	United States	Parallel	Open	DM; overweight; no CKD; coronary heart disease	20–25 g carbohydrates/day in weeks 1–2 depending on baseline weight, then increasing by 5 g carbohydrates/week	25% fat	12	86	88
Due, 2008 (24)	Denmark	Parallel	Open	BMI 28–36; NP	45% carbohydrate, 40% fat (20% MUFA), 15% protein	60% carbohydrate, 25% fat (20% MUFA), 15% protein	6	56	73
Ebbeling, 2007 (25)	United States	Parallel	Open	BMI ≥30; no DM	40% carbohydrate, 35% fat, 25% protein; low-glycemic-load foods and limited intake of high-glycemic-load foods	20% fat, 55% carbohydrates, 25% protein; low-fat grains, vegetables, fruits, and legumes and limited intake of added fats sweets and high-fat snacks	18	78	62
Elhayany, 2009 (26)	Israel	Parallel	Open	DM; BMI 27–34	35% carbohydrate, 45% fat (23% MUFA), 20% protein; 4–6 meals/day, only low-glycemic-index carbohydrates	30% fat (10% MUFA), 20% protein, 50% carbohydrate; 4–6 meals/day, mixed glycemic index carbohydrates	12	72	71
Foster, 2003 (9)	United States	Parallel	Open	No DM; obesity	20 g carbohydrates/day, gradually increasing until a stable and desired weight is achieved	25% fat, 60% carbohydrate, 15% protein; limited energy intake of 1200–1500 kcal/day for women and 1500–1800 kcal/day for men	12	61	57
Foster, 2010 (17)	United States	Parallel	Open	BMI 30–40; no DM; normal BP	20 g carbohydrates/day (low-glycemic index-vegetables) during weeks 1–12, increasing by 5 g/week through consumption of a limited amount of fruits, more vegetables, and eventually small quantities of whole grains and dairy products, until a stable and desired weight was achieved	30% fat, 55% carbohydrate, 15% protein; energy intake limited to 1200–1500 kcal/day for women and 1500–1800 kcal/day for men	24	58	68
Frisch, 2009 (27)	Germany	Parallel	Open	BMI >27; no CVD or type 1 DM	40% carbohydrate, 35% fat, 25% protein	30% fat, 55% carbohydrates, 15% protein	6	95	89
Gardner, 2007 (6)	United States	Parallel	Single	Female sex; BMI 27–40; normal BP; no DM CVD; NP	≤20 g carbohydrates/day for the first 2–3 months and ≤50 g carbohydrates/day for the subsequent phase	10% fat	12	88	78
Hockaday, 1978 (28)	United Kingdom	Parallel	Open	DM; no myocardial infarction or stroke	40% carbohydrates, 40% fat, 20% protein	25% fat, 54% carbohydrates, 21% protein	12
Iqbal, 2010 (29)	United States	Parallel	Open	DM; obesity; no CKD	30 g/day carbohydrates	30% fat with a deficit of 500 kcal/day	24	40	54
Klemsdal, 2010 (14)	Norway	Parallel	Open	No DM or CVD; ≥1 METS components and BMI 28–40 for men and 28–35 for women	30%–35% carbohydrates, 35%–40% fat, 25%–30% protein	30% fat, 55–60% carbohydrate, 15% protein,	12	78	84
Lim, 2009 (30)	Australia	Parallel	Open	BMI 28–40; ≥1 CVD risk factors; No CVD or DM	4% carbohydrate, 60% fat (20% saturated fat), 35% protein	10% fat (3% saturated fat), 70% carbohydrate, 20% protein	15	63	64
McAuley, 2006 (31)	New Zealand	Parallel	Open	Female sex; prediabetes; NP	≤20 g carbohydrates/day during weeks 1–2, increasing to 50 g/day by 8 weeks and continuing thereafter	30% fat, 55% carbohydrate, 15% protein	12	77	75
Moran, 2006 (32)	United Kingdom	Parallel	Open	Female sex; overweight with polycystic ovary syndrome; no DM; NP	120 g carbohydrates/day	50 g fat/day	6	78	57
Sacks, 2009 (13)	United States	Factorial	Double	No DM or CVD; BMI >25	35% carbohydrate, 40% fat, 25% protein	30% fat, 55% carbohydrate, 25% protein	24	83	78
Shai, 2008 (11)	Israel	Parallel	Open	DM or CVD or BMI >27; NP	20 g carbohydrates/day for the 2-month induction phase and with a gradual increase to ≤120 g/day to maintain the weight loss	30% fat (10% saturated fat) with 1500 kcal/day for women and 1800 kcal/day for men, and 300 mg cholesterol/day	24	78	90
Stern, 2004 (12)	United States	Parallel	Open	BMI ≥35; no CKD	<30 g carbohydrates/day	<30% fat with a deficit of 500 kcal/day	12	69	63
Swenson, 2007 (33)	United States	Parallel	Single	Gastric bypass surgery; obesity	South Beach diet	16% fat, 72%–74% carbohydrate, 10–12% protein	6
Thomson, 2010 (34)	United States	Parallel	Open	Female sex; stage 1–2 breast cancer; BMI 25–35; No DM, CKD, or CVD	35% carbohydrates, 35%–40% fat, 25%–30% protein	25% fat, 55%–60% carbohydrates, 15%–20% protein	6	91	68
Yancy, 2004 (10)	United States	Parallel	Open	BMI 30–60; dyslipidemia; NP	<20 g carbohydrates/day during weeks 1–10, increasing by 5 g/week until body weight was maintained	<30% fat (<10% saturated fat)	6	76	57

Abbreviation: BMI, body mass index; BP, blood pressure; CKD, chronic kidney disease; CVD, cardiovascular diseases; DM, diabetes mellitus; LCD, low-carbohydrate diets; LFD, low-fat diets; METS, metabolic syndrome; MUFA, monounsaturated fatty acid; NP, no pregnancy.

^a Weight (kg)/height (m)².