Low Carb Diet Trials: Lim, et al (2009)

Long-term effects of a low carbohydrate, low fat or high unsaturated fat diet compared to a no-intervention control

 

Participants and Diets

 

113 people with a BMI 28-40 and aged 20-65 and with at least one CVD risk factor other than obesity were randomised to one of 4 diet groups:

 

1.      Very low carbohydrate diet (VLC)

2.      Very low fat diet (VLF)

3.      High unsaturated fat diet (HUF)

4.      Control

 

At baseline there were no differences between the three experimental groups (VLC, VLF, HUF), but the control group had lower total cholesterol, ApoB, SBP and DBP (Table 1).  The 3 diet groups received intensive support for the first 3 months then asked to maintain the diet for an additional 12 months

 

Pro:Fat:Carb (SFA)	VLC	VLF	HUF
3 Months	31:54:12 (17.7)	20:13:66 (5.1)	21:28:49 (6.0)
6 Months	24:39:33 (13.9)	21:26:51 (10.2)	21:28:48 (9.4)
9 Months	22:37:39 (14.0)	19:27:53 (11.1)	21:29:50 (10.1)
12 Months	21:39:38 (14.4)	22:27:51 (10.4)	20:29:48 (11.1)
15 Months	24:38:37 (13.2)	20:28:51 (10.7)	24:30:43 (9.9)
Target	35:60:4 (20.0)	20:10:70 (3.0)	20:30:50 (8.0)

 

Calorie Intake	VLC	VLF	HUF
3 Months	1848	1679	1837
6 Months	1767	1672	1547
9 Months	1628	1801	1688
12 Months	1853	1895	1708
15 Months	1641	1903	1581
Target	1560	1560	1560

 

Notably the groups had very good adherence to the diets at 3 months, which declined when the intensive support was gone

 

Results

 

The three diet groups had greater weight loss than the control group but there weren’t significant differences between groups (although at 15 months HUF was close with p = 0.065 vs. VLF)

 

Weight Loss (kg)	VLC	VLF	HUF
3 Months	−8.0 (2.8)	−6.7 (3.5)	−6.3 (2.9)
15 Months	−2.9 (4.9)	−2.1 (4.7)	−3.9 (6.3)

 

 

Below is table 3 (except weight loss).  ‘d’ refers to changes compared to baseline; ‘x’ and ‘y’ refer to significant differences between groups.  I’ve bolded cells containing those letters.  Overall there weren't much of difference between groups or compared to baseline, with most happening at 3 months, except blood pressure, which improved quite a bit at 15 months

 

		VLC	VLF	HUF
Cholesterol, mmol/L	3 months	0.1 (1.1)	−0.5 (0.8)	−0.5 (0.6)
	15 months	−0.4 (0.8)	−0.3 (0.8)	−0.3 (1.2)
HDL-C mmol/L	3 months	0.1 (0.2)x	−0.1 (0.2)y	−0.1 (0.2)y
	15 months	0.1 (0.3)	0.1 (0.3)	−0.1 (0.2)
LDL-C (mmol/L)	3 months	0.3 (1.0)x	−0.4 (0.6)y	−0.6 (1.1)y
	15 months	−0.3 (0.7)	−0.3 (0.7)	−0.1 (1.1)
Triglyceride mmol/L	3 months	−0.7 (0.6)x	−0.1 (0.6)y	−0.2 (0.5)y
	15 months	−0.2 (0.7)	0.1 (0.9)	−0.3 (0.8)
Chol:HDL	3 months	−0.2 (0.2)	−0.2 (0.1)	−0.2 (0.2)
	15 months	−0.2 (0.2)	−0.3 (0.1)	−0.02 (0.4)
Trig:HDL	3 months	−0.6 (0.1)x	−0.03 (0.1)y	−0.04 (0.1)y
	15 months	−0.09 (0.2)	0.05 (1.8)	−0.1 (0.2)
ApoB g/L	3 months	−0.1 (0.3)	−0.1 (0.2)	−0.1 (0.1)
	15 months	0.1 (0.3)	−0.1 (0.2)	−0.1 (0.3)
CRP mg/L	3 months	1.2 (12.2)	0.3 (5.0)	−0.5 (3.2)
	15 months	−1.7 (6.7)d	−2.1 (2.5)d	−1.8 (3.1)
Folate nmol/L	3 months	−0.7 (4.2)	3.6 (6.2)	0.9 (8.4)
	15 months	−1.3 (8.9)	0.1 (9.2)	−6.0 (8.7)d
Homocysteine μmol/L	3 months	0.6 (1.4)x	−0.5 (1.5)y	0.1 (1.1)xy
	15 months	0.4 (1.2)	−0.6 (1.1)d	0.1 (1.2)
Vitamin B12 pmol/L	3 months	6.8 (61.4)	−4.6 (49.1)	−4.1 (78.7)
	15 months	33.5 (76.9)d	18.9 (66.9)	41.9 (73)d
Fasting insulin mU/L	3 months	−3.9 (3.7)x	3.0 (13.8)y	−1.8 (2.7)x
	15 months	−1.5 (4.4)	0.5 (5.5)	−1.7 (4)
Fasting glucose, mmol/L	3 months	−0.1 (0.3)	0.1 (0.6)	−0.2 (0.4)
	15 months	0.1 (0.3)	0.3 (0.6)	−0.4 (1)
SBP mmHg	3 months	−10.5 (12.7)	−7.1 (12.6)	−3.1 (14.5)
	15 months	−10.6 (10.6)d	−6.0 (13.3)d	−5.4 (13.3)
DBP mmHg	3 months	−3.8 (9.5)	−2.1 (11)	−2.0 (9.3)
	15 months	−6.6 (12.1)d	−7.5 (8.7)d	−9.0 (9.3)d

 

“The attrition rate was 43%, 40%, 50% and 17% for VLC, VLF, HUF and the control group respectively (P = 0.098).”