Untitled

Table 4 Continued
Duration Intervention Control Compliance Results
Trial design a
Reference/country Participants a
Feeding phase: low GI
9.95 kg, 6.9 kg fat
mass. High GI 9.3 kg,
4.5 kg fat mass.
Additional weight
change in free-living
phase: 1.8 kg for low
GI and 1.6 kg for
high GI. No significant
differences between
groups
Diet records: no
significant difference
in GI between
groups after
free-living phase
Feeding phase:
hypocaloric (3128 kJ
per day deficit), high
GI. Free living: advised
to continue this diet
Feeding phase:
hypocaloric (3138 kJ
per dcay deficit), low
GI. Free living: advised
to continue this diet
F/M adults. Low GI, Randomized parallel 12-week feeding
n ¼ 10, BMI 37.7. High
phase (all foods
GI, n ¼ 9, BMI 34.6.
provided) þ 24-week
31% lost to follow-up
free-living phase with
in feeding phase.
counseling
During the free living
phase n ¼ 4 of the low
GI and n ¼ 1ofthe
high-GI group lost.
No intention to treat
analysis
(Raatz et al., 2005)
US
Abbreviations: BMI, body mass index (kg/m); F, female; GI, glycemic index; M, male.
Values are means (s.d.) unless reported otherwise.
a
None of the studies reported on blinding of outcome assessors or allocation concealment.
Carbohydrate intake and obesity
RM van Dam and JC Seidell
between the diets, and given the magnitude of the effect
other modest differences between the intervention diets may
also have been responsible. In a Danish study, almost half of
the foods were provided, allowing better control of differences
between the diets, and recovery of lithium from the
provided breads was used to monitor compliance (Sloth
et al., 2004). Despite the substantial differences in the GI of
the diets, no statistically significant effects on body weight
or fat mass were observed although a small beneficial effect
could not be excluded either. In the studies by Raatz et al.
(2005) (‘free living phase’ of the study) and Carels et al.
(2005) low-GI dietary advice did not have effects on body
weight as compared with the control interventions, but
achieved differences in dietary GI were small. In two
Canadian studies, provision of key low-glycemic foods
resulted in modest differences in dietary GI, but did not
result in a lower body weight over 4 or 6 months as
compared with the provision of high-GI foods (Tsihlias
et al., 2000; Wolever and Mehling, 2003). In contrast, weight
loss tended to be somewhat larger for the high-GI as
compared with the low-GI diet. A larger randomized
intervention study that evaluates substantial differences in
the dietary GI in the absence of other dietary differences
with the control group would be of interest. In addition, it
may be warranted to distinguish further between different
types of low-GI foods. However, the currently available data
provides little support for an important role of the dietary GI
in weight management.
Intervention studies of the GL and weight change
Four studies aimed to test the effects of low-GL diets on body
weight (Table 5). The effect of low-GL dietary advice on body
weight was tested in 16 obese adolescents (Ebbeling et al.,
2003). The low-GL advice resulted in a substantially larger
reduction in fat mass as compared with the conventional
control diet. Given the very small resulting differences in
dietary GI and carbohydrate intake between the intervention
and control diet, effects on body fat may also have resulted
from other beneficial characteristics of the recommended
foods (non-starchy vegetables, fruits, legumes, nuts, dairy) or
a greater acceptation of the ad libitum approach by the
adolescents (Ebbeling et al., 2003). The same low-GL advice
resulted in greater changes in GI, carbohydrate intake, and
GL in a trial in young adults, but did not result in a
statistically significant greater reduction in body fat or fat
mass (Ebbeling et al., 2005). In a substantially larger 12-week
Australian trial, four diets were compared: (A) a high-GI/
high-carbohydrate diet (highest GL), (B) a low-GI/highcarbohydrate
diet, (C) a high-GI/high-protein diet and (D)
a low-GI/high-protein diet (lowest GL) (McMillan-Price et al.,
2006). No significant differences in weight loss or decrease in
fat mass were found, although the percentage with at least
5% weight loss was greater for diets B and C than for the
other diets. Also, in a subgroup analysis in women, more fat
mass was lost for diets B and C than for the other diets.
S91
European Journal of Clinical Nutrition