Milling & Baking News - September 16, 2014 - 21



Low-carb dieters lose more
weight in year-long study
PHILADELPHIA - Dieters assigned a low-carbohydrate diet over
a 12-month period fared better than
those on a low-fat diet as measured
by weight loss and reduction in cardiovascular risk factors, according to
research recently published.
The findings, "Effects of Low-Carbohydrate and Low-Fat Diets," representing the latest salvo in the decades
old debate over the efficacy of macronutrient-cutting diets, were published
in the Sept. 2 edition of Annals of Internal Medicine.
The study was published by a team
led by Lydia Bazzano, an associate
professor of epidemiology at Tulane
University and Tian Hu, a doctoral
fellow at Tulane University School of
Public Health. The primary funding
source for the study was the National
Institute of Health.
Participants in the study were overweight or obese men and women who
did not have clinical cardiovascular
disease, type II diabetes, or kidney disease, use of prescription weight loss
medications, surgery, and those with
weight loss greater than 6.8 kg (about
15 lbs) within six months of study entry. A total of 148 participants were
included. Roughly half of the subjects
were black, a group the researchers
said were underrepresented in earlier
research.
The participants were divided into
two groups, half of whom were told
to consume less than 40 grams of carbohydrates per day (the low-carbohydrate group) and the other half were
told to consume less than 30% of their
daily energy intake from fat.
Participants received dietitian guidance - weekly and individualized for
the first four weeks; every other week
in small group counseling sessions
the next five months; and monthly in
small groups for the final six months.
Data were collected using two 24hour dietary recall methods. One recall reflected consumption on a weekday, the other on a weekend. The recalls were done at the start, and at 3, 6
and 12 months to track dietary intake.
At baseline, reported dietary composition was similar between those in the
low-carbohydrate and low-fat groups.
Also, physical activity levels remained
similar throughout the study.
The participants in the low-carbohydrate group showed significantly
greater body weight reduction than
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those in the low-fat group (mean
difference in change at 12 months:
-7.7 lbs) and showed significantly
greater proportional reductions in
fat mass (mean difference in change
at 12 months: -1.5%). Changes in

'What is clear is that
adhering to a diet of 40
grams of carbohydrate
per day for any amount
of time is really difficult,
even with low-carb
meal supplements and
nutrition counseling.'
- Elle Penner,
Huffington Post

waist circumference favored the lowcarbohydrate diet early in the study
but did not differ significantly by the
end. Also comparable between the
two groups were 12-month serum
levels of L.D.L. cholesterol - little

Nutrition and Health

changed. By contrast, H.D.L. cholesterol increased significantly more in
the low-carbohydrate group than in
the low-fat group.
"Our study found that a low-carbohydrate diet induced greater weight
loss and reductions in cardiovascular
risk factors at 12 months than a low-fat
diet," the researchers said.
"Findings from this trial may offer
new evidence for the recommendation
of a low-carbohydrate diet to obese
persons as an additional nonpharmacologic approach for weight loss and
reduction of cardiovascular disease
risk factors," the authors said.
The authors criticized earlier studies
for failing to examine a "typical lowcarbohydrate diet," which they defined
as restricting carbohydrates to less than
20% of daily energy intake. The authors
estimated participants in their study
"achieved an average of 30% of daily
energy from carbohydrates." They did
not describe this difference as a shortcoming of their research. Over the
course of the 12 months, the low-carbohydrate dieters consumed between
93 and 127 grams of carbohydrates per
day (versus the objective of 40 grams).
At the 12-month mark, the "low-carbohydrate dieters" were consuming 35%

Daily dietary composition in the low-fat and
low-carbohydrate diet groups at baseline and 12 months
Variable

Baseline
Low-fat Low-carbohydrate
diet
diet

12 months
Low-fat Low-carbohydrate
diet
diet

Energy kcal
Carbohydrate, g
Total fiber, g
Soluble fiber, g
Insoluble fiber, g
Fat, g
SFA, g
MUFA, g
PUFA, g
ω-3 Fatty acid, g
Carbohydrate, % kcal
Protein, % kcal
Fat, % kcal
SFA, % kcal
MUFA, % kcal
PUFA, % kcal
Folate, mg
Median β-carotene (IQR), mg
Vitamin C, mg

2,034.0
242.0
16.7
5.1
11.5
80.7
27.6
29.3
17.1
2.0
46.0
17.6
34.7
11.6
12.7
7.5
0.4
0.8
78.4

1,527.0
198.0
15.6
5.1
10.4
52.4
15.8
20.0
12.2
1.3
54.0
18.6
29.8
9
11.3
6.9
0.4
1.0
82.5

1,998.0
242.0
18.5
5.8
12.5
75.6
24.7
28.1
16.7
1.9
48.1
17.3
32.5
10.5
12
7.3
0.4
0.5
88.6

1,448.0
127.0
15.1
5.2
9.9
69.0
23.3
25.8
14.2
1.6
34.0
23.6
40.7
13.4
15.3
8.6
0.3
0.4
72.5

Source: Annals of Internal Medicine

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Milling & Baking News - September 16, 2014

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