T YPE OF C ARBOHYDRATES FOR P REVENTION OF W EIGHT G AIN

9.6.2 T YPE OF C ARBOHYDRATES FOR P REVENTION OF W EIGHT G AIN

Five prevention trials among adults were identified that resulted in a significant increase in dietary fiber intake relative to controls. 129–132,136 Two 129,131 detected a decrease in weight or BMI relative to controls. The others found no significant impact. However, only two aimed to increase fiber intake per se, 129,130 one of which favorably impacted weight. Another aimed to increase complex carbohydrates 131 and also favorably impacted weight. Both the trial that aimed only to increase fruit and vegetable intake 132 and the trial that only targeted a decrease in dietary fat 136 failed to significantly impact weight relative to controls. It is difficult to draw conclusions

Carboh

TABLE 9.3 Prevention Trials among Adults That Targeted or Impacted Carbohydrate Intake (in Descending Order by Sample Size)

ydrates and Obesity

Results: Impact on Measure of

Length of

Relevant Target Behaviors

Adiposity

Author, Year

Intervention

Direction of

Study Study Population,

and Timing of

Change

Control Location

Name Sample Size, Age,

Study Design and

Follow-Up

Relative to

Reported Change

Control Group

Variables Comments

Gender No significant Polyp

Lanza, 2001 2079 adults with large- Randomized

4 years

↓ Dietary fat ↓ Dietary fat (% and g/day)

differences at Prevention

bowel adenomatous

controlled trial;

↑ Intake of fruits

↑ Intake of fruits and

(Weight)

baseline between Trial

polyps, 35–89 years

individualized

and vegetables

vegetables (servings/MJ

groups for gender, U.S.

old,

instruction and

↑ Dietary fiber

and g/day)

88–91% white

counseling

↑ Fiber (g/MJ)

age, minority race,

program to prevent

0 Change in total calories

education, marital

the recurrence of

↑ Carbohydrates (%)

status, BMI, current

adenomatous

↑ Protein (%; men)

smoking, current

polyps

↑ Calcium (men),

aspirin use, or

↑ Whole grains (g/day)

vigorous and

↓ High-fat foods (g/day;

moderate physical

red/processed meats,

activity

high-fat dairy and desserts)

↑ Low-fat alternatives (g/day)

Carboh

0 Age, stage of No significant Women’s

Rock, 2001 1010 women,

Randomized

1 year

↑ Fruit and

↑ Fruit and vegetable intake

cancer at differences in age, Healthy

18–70 years old, 86%

controlled trial;

vegetable intake

(servings/1000 kcal)

(Weight)

ethnicity, education Eating and

non-Hispanic white

individualized

↑ Fiber intake

↑ Fiber intake (g/1000 kcal)

initial

ydrates and Obesity

dietary

↓ Percentage of

↓ Percentage of calories

diagnosis, level, stage at

overweight diagnosis, or BMI (WHEL)

Living

counseling; tested

calories from

from dietary fat

between intervention Study

effect of low-fat,

dietary fat

↑ Percentage of calories

status,

menopausal and comparison California,

high-vegetable

from carbohydrates

groups at baseline Arizona,

diet on patients at

status

*Change in vegetable Texas, and

risk for breast

intake was inversely Oregon

cancer recurrence

associated with weight change

Bhargava, 926 postmenopausal

Baseline values were 2002

Randomized control

1 year

↓ Energy intakes

↓ Fat intake (g) (saturated

similar across groups. Women’s

women, 50–70 years

trial; group dietary

from fat to ~20%

fat, monounsaturated fat,

(Weight)

*In both intervention Health

old, 28% black, 16%

counseling; weight

calories

and polyunsaturated fat)

and control groups, Trial:

Hispanic, 54% white

gain prevention

↓ Intake of

↓ Energy intake

(Waist

weight change was Feasibility

intervention

saturated fat

↑ % total calories from

circumference)

explained by changes Study in

↑ Consumption of

carbohydrates

in carbohydrate and Minority

fruits, grain

(Hip

saturated, Populations

products, and

circumference)

monounsaturated, Georgia,

vegetables

and polyunsaturated Alabama,

fats and Florida

TABLE 9.3 (continued)

352 Prevention Trials among Adults That Targeted or Impacted Carbohydrate Intake (in Descending Order by Sample Size)

Length of

Author, Year

Intervention

Study Study Population,

and Timing of

Results:

Impact on Measure of Location

Name Sample Size, Age, Study Design and

Relevant Target Behaviors

Adiposity

Comments

Boyd, 1997 786 women with

Baseline Canadian

Randomized

2 years

↓ Intake of dietary ↓ Mean percentage of

characteristics were Diet and

mammographic

controlled trial;

fat to 15% of total

calories derived from fat

(Weight)

similar across Breast

(fell from 33 to 21%)

(intervention and Cancer

aged 30–65 years,

individual dietary

↑ Intake of

Protein intake as a percent

control) groups Prevention

race/ethnicity not

counseling to

complex

of total calories was

specified

determine whether

carbohydrates

unchanged

Study Group

adoption of low-

↑ Carbohydrate intake

Toronto,

fat, high-

(rose from 50 to 61% of

Hamilton,

carbohydrate diet

calories)

London, and

would reduce the

↑ Intake of total dietary

Windsor in

area of

fiber (from 17.2 to 20.3

Ontario

radiologically

g/day)

dense breast tissue

Functional F

Smith- 201 adults with

↑Intake of 0 Baseline No significant Warner,

Randomized

1 year

↑ Intake of fruits

value, gender differences at 2000

adenomatous large-

controlled trial;

and vegetables

fruits/vegetables

(Weight)

baseline between Minnesota

0 groups for age, Cancer

bowel polyps, 30–74

individual diet

(servings/day)

years old, 99% white

counseling to

0 Change energy intake or

prevent colon

protein (%)

(BMI)

gender, household

ood Carboh

income, education, Research

Prevention

cancer

↓ Dietary fat (%)

marital status, Unit

↑ Carbohydrate (%)

employment, Intervention

↑ Fiber (g/day)

ethnicity, smoking, Study

BMI, alcohol intake, Minneapolis,

ydrates

or use of nutrient

MN supplements

Carboh

0 No significant Reading and

Cox, 1998 125 adults, 16–65 years Randomized

8 weeks

↑ Intake of fruits

↑ Intake of fruits and

differences at Glasgow,

old

controlled trial;

and vegetables

vegetables (g/day;

(Weight)

baseline between U.K.

education to

attenuated but remained

(Both

ydrates and Obesity

promote fruit and

after 1-year follow-up)

groups for age,

vegetable

0 Difference in calories

intervention and

gender, occupation,

consumption

↓ (in both intervention

control groups

household income,

and control groups), fat

gained weight)

employment status, or (%; except significant ↓ BMI

in subgroup with baseline fat of >35%), or starch (%)

↑ CHO (%) and total sugars (%)

Simon, 1997 133 women at high risk Randomized

0 Study site No p values were Detroit, MI,

3 months of

↓ Dietary fat intake ↓ Mean percent caloric

reported for dietary and Wichita,

for developing breast

Controlled trial;

intensive

to 15% of total

intake from fat (from 36 to (Weight and

changes but they KS

cancer,

combination of

intervention, 12

calories

18%); this change was

percent body fat)

aged 18–67 years, 89%

appeared to be Caucasian, 9% African

education, goal

months follow-

maintained at 12 months

significant; women in American, 2%

setting, evaluation,

up

↓ Mean caloric intake at 12

the low-fat diet group Hispanic

feedback, and

measurements

months compared to

participant self-

baseline

lost an average of 3 lb

monitoring,

↑ Dietary fiber intake at 3

and women in the

included both

months; increase was

nonintervention

intensive

maintained at 12 months

group lost an average

individual

of 5 lb; % body fat ↓

counseling

slightly for both

sessions and group

groups

meetings; weight reduction was not encouraged

354 TABLE 9.4

Prevention Trials among Children That Targeted or Impacted Carbohydrate Intake (in Descending Order by Sample Size)

Relevant Targeted Behaviors

Results:

Length of

Impact on Measure of Adiposity

Intervention

Direction of

Author, Year Study Population,

and Timing

Change

Study Name Sample Size, Age,

Study Design

of Follow-

Relative to

Location Ethnicity

and Strategies Up Measure

Targeted

Reported Change

Control Group Control Variables Comments

No significant Child and

Luepker, 1996 5106 children (school- Randomized

3 school years ↓ Dietary fat

School level:

0 School level:

Observation days differences at Adolescent Trial

level data), 4019

controlled trial;

↑ Physical activity

↓ Fat (%) in school

(BMI)

0 within semester baseline between for

children (individual-

school-based

lunch menus

and lessons within groups at school- Cardiovascular

level data), grades

multicomponent

↓ Dietary energy in

(TSF or SSF)

observation days, level for Health

3–5, 69% white, 13%

CVD risk

school lunch menus

location of the environmental, (CATCH)

African American,

reduction

↑ Physical activity

lesson, specialty of behavioral, San Diego,

14% Hispanic

program

intensity in PE

psychosocial, and Houston, New

(education, PE,

Individual level:

the teacher

school lunch, and

↓ Rise in dietary energy

Functional F

Individual level: risk factor data

Baseline value, Not explicitly stated Minneapolis

Orleans, and

home programs

(MJ/d)

for half of the

↓ Dietary fat (%)

gender, ethnicity, in paper, but

families)

↑ CHO intake (%)

CATCH field site, prevention of

0 Change in protein

random effect of obesity was not a

intake (%)

school with site goal of CATCH, but

ood Carboh

↑ vigorous physical

and intervention rather, it aimed to

activity

group

avoid growth retardation

ydrates

Carboh

0 Age, site, gender, Not explicitly stated CATCH

Nader, 1999 3714 children, grades

Randomized

3-year follow- ↓ Dietary fat

↓ Dietary fat (%)

ethnicity, intraclass in paper, but San Diego,

controlled trial;

up (after 3-

↑ Physical activity

↑ CHO (%)

(BMI)

0 correlation within prevention of Houston, New

(73% of original

school-based

year

0 Change protein (%)

ydrates and Obesity

↑ Vigorous physical

(TSF or SSF)

school and among obesity was not a

students, gender × goal of CATCH, but Minneapolis

Orleans, and

CVD risk

activity

reduction

↓ (Note: dietary energy

ethnicity

rather, it aimed to

program

at end of 3-year

interaction

avoid growth

(education, PE,

intervention gone by

retardation

school lunch, and

3-year follow-up)

home programs for half of the families)

The Writing 663 children with

0 Gender, baseline No significant Group for the

Randomized

3 years

↓ Dietary fat

↓ Total fat (%)

differences at DISC

elevated LDL

controlled trial;

energy and other

↓ Total energy (kJ/d)

(BMI)

value

0 baseline between Collaborative

cholesterol,

clinic-based,

nutrients at RDA

↑ Protein (%)

groups for age, Research Group,

0 gender(?) (appears 1995

race/ethnicity not

family-oriented

0 Change in diet, Ca,

so, but not explicitly The Dietary

specified

dietary

Zn, Fe, vitamins A and

counseling

(Sum TSF, SSF,

stated),

Intervention

anthropometry, Study in

program to

0 Change in serum

and suprailiac

0 and blood pressure; Baltimore, MD,

blood lipid levels, Children

reduce LDL

ferritin, Zn, retinol

skinfold)

cholesterol

small differences in Chicago, IL,

(WHR)

dietary intake, with Iowa City, IA,

intervention group Newark, NJ,

having slightly New Orleans,

lower % energy LA, and

from PUFA and Portland, OR

slightly higher intakes of vitamin B 6 and Zn Intervention group had a slightly higher proportion with

household income <$20K

TABLE 9.4 (continued)

Prevention Trials among Children That Targeted or Impacted Carbohydrate Intake (in Descending Order by Sample Size)

Length of Intervention

Author, Year Study Population,

and Timing

Study Name Sample Size, Age,

Study Design

of Follow-

Relevant Targeted Behaviors

Results:

Location Ethnicity

and Strategies Up Measure

Impact on Measure of Adiposity Comments

0 Age, ethnicity, At baseline, Know Your Body,

Resnicow, 1992 1209 children, 6–13

Nonrandomized

1 1 / 2 -year

↑ Health knowledge

0 Significant

gender, baseline intervention students comprehensive

years old,

control trial;

intervention

↑ Fiber content of

differences in dietary

(BMI)

did not significantly school health

foods served in

indices

values

Hispanic population

comprehensive

3-year follow-

school

↑ Health knowledge at

differ with regard to

sex, total program

education school health

up measure

↓ Fat content of

3-year follow-up

cholesterol, systolic New York

education

foods served in

↑ Number of servings

program

school

of vegetables and

blood pressure,

(classroom

↑ Vegetable and

heart-healthy foods

BMI, health

curriculum,

heart-healthy

↓ Number of servings

attitudes, and self-

schoolwide

indices

of meat and desserts

efficacy; they were

health activities,

significantly

and

younger, more likely

Functional F

environmental

to be Hispanic, and

modifications)

had significantly lower health

knowledge and fruit intake scores than control students

ood Carboh

ydrates

Vandongen, 1995 869 children, 10–12

Gender, baseline West Australia

Randomized

9 months

↑ Consumption of

↓ % Total energy from

years old, considered

controlled trial;

fruit, vegetables,

sugar (boys only)

to be representative

school-based

whole-grain bread

↓ % Total energy from

skinfolds, boys

sample of the

nutrition and

and cereal relative

fat (girls only)

and girls)

socioeconomic mix of

fitness program

to other foods

↓ % Total energy from

the community in

to improve

↓ Consumption of

saturated fat (girls

(Subscapular

ydrates and Obesity

West Australia,

cardiovascular

fatty, sugary, and

only)

skinfolds,

race/ethnicity not

risk factors

salty foods relative

0 Change in total

boys and girls)

specified

to other foods

energy (boys and

girls) ↑ % Total energy from (% Body fat,

boys and girls)

protein (boys only) ↑ Fiber intake, g/day

(boys and girls)

(BMI, boys and girls)

Burke, 1998 720 children,

0 Gender, baseline At baseline, there Western Australia

Randomized

20-week (2

↑ Duration and

↑ Physical fitness (boys

were no significant race/ethnicity not

11 years old,

controlled trial;

school

frequency of

and girls)

(BMI, boys and

values

differences in specified

school- and

terms)

physical activity

0 Change in physical

↓ Consumption of

activity (boys and

dietary variables,

physical

and 6-month

fat, sugar, and salt

girls)

(Subscapular

time spent in leisure-

enrichment

follow-up

↑ Fiber intake

↓ TV watching (boys

skinfolds, girls

time physical

program for

activity, or hours of

children at

0 Dietary change (boys

TV watching

higher risk of

and girls)

(Triceps

cardiovascular

skinfolds, boys

disease

and girls)

Donnelly, 1996 44 subjects, 64 controls,

Nonrandomized

2 school years ↓ Intake of fat

0 Significant change in

0 Schools were

Rural Nebraska grades 3–5, subsample

controlled trial;

↓ Intake of

total energy, % kcal

(Weight, BMI,

matched for

of 11 subjects and

ethnicity/SES and 25 controls with 22%

school-based

cholesterol

from fats,

and body fat %

multicomponent

↓ Intake of sodium

body fat,

characteristics race/ethnicity not

program

↑ Intake of fiber

proteins, or fiber

weighing)

0 (grade, height, specified

(nutrition

↑ Physical fitness

↓ Intake of sodium

education,

and knowledge and

(Attenuation of

weight, BMI, mile-

modified school

awareness of diet in

obesity —

run time)

lunches, and

health

subjects with

enhanced

body fat of

physical activity

program)

TABLE 9.4 (continued)

Prevention Trials among Children That Targeted or Impacted Carbohydrate Intake (in Descending Order by Sample Size)

Length of Intervention

Author, Year Study Population,

and Timing

Study Name Sample Size, Age,

Study Design

of Follow-

Relevant Targeted Behaviors

Results:

Location Ethnicity

and Strategies Up Measure

Impact on Measure of Adiposity Comments

Sahota, 2001 203–303 children, 8–10

No significant Active

Randomized

12 months

Influence of diet and

↑ Vegetable intake

0 Gender, age,

baseline BMI differences were Programme

years old, some ethnic

controlled trial;

physical activity

↓ Fruit intake in obese

(BMI)

found between the Promoting

minority children in

intervention and Lifestyle in

sample

multidisciplinar

↑ Consumption of

↑ Intake of foods and

comparison pupils Schools

y intervention to

fruits and

drinks high in sugar in

for any of the (APPLES)

reduce risk

vegetables

overweight children

measures at baseline Leeds, U.K.

factors for

↓ Consumption of

↑ Sedentary behavior in

obesity

foods high in fat

the overweight

↓ Consumption of

children

foods and drinks high in sugars

Functional F

ood Carboh

ydrates

Carboh

0 No significant Childhood Weight

Epstein, 2001 27 intervention families

Randomized

6-month

↑ Fruit and vegetable

↑ Fruit and vegetable

differences at Control and

(at least 1 obese (BMI

intake (servings/day)

(Percentage of

baseline between Prevention

> 85th percentile)

trial; parent-

and

↓ High-fat and high- ↓ High-fat and high-

overweight)

ydrates and Obesity

parent + a nonobese

focused

1-year follow-

sugar food intake

sugar foods

groups for gender,

age, weight, % Buffalo, NY

Program (BMI < 85th

behavioral

up measure

(servings/day)

percentile) child, 6–11

overweight, family years old)

intervention on

parent and child

history of obesity

eating changes,

and chronic diseases

and weight

(except for more

control

HTN in families in

treatment for

fat/sugar group),

parents

food habits, child feeding practices, and confidence in making choices Correlations showed no differences by age or gender in outcomes

Functional Food Carbohydrates

regarding the independent impact of dietary fiber on adiposity given the limited number of studies and the variability in the combination of target behaviors in each

intervention. However, it appears that dietary fiber is sometimes, but not always, effective in preventing weight gain. Interventions may be more effective when they

explicitly target fiber intake from a variety of sources, including whole grains. Four programs specifically targeted an increase in fiber intake among chil- dren. 137–140 Only one, however, measured and detected an increase in fiber intake among subjects compared to controls. 138 Therefore, once again it is hard to arrive at a conclusion regarding the impact of a reduction in fiber intake, when most of the studies were unable to produce a detectable change. Although half of these four studies did observe an impact on adiposity, 138,139 this impact was observed only with regard to skinfolds, and not BMI. All of these programs aimed to reduce fat or sugar as well as increase fiber, and two of them also targeted physical activity, 139,140 again making it difficult to attribute program impact (or lack thereof) to any specific targeted behavior. We can conclude only that increases in fiber intake may be part of an effective strategy to prevent overweight in children.

Only one study examined sugar intake among adults. 133 This study, which aimed to increase fruit and vegetable intake, resulted in an increase in total sugar intake and did not have a significant impact on weight of subjects relative to controls. Based on this limited data, no conclusions can be drawn regarding sugar intake among adults for the prevention of weight gain.

Four studies were identified that specifically targeted the reduction of sugar or foods high in sugar among children. 125,138,139,141 Three of these were school-based

randomized controlled trials, and the other 125 was a family-focused behavior inter- vention that did not include a control group. The only study that detected a decrease in the intake of high-sugar foods did not observe an impact on adiposity. 125 Another study 141 actually detected an increase in the intake of high-sugar foods and beverages relative to controls and observed no impact on BMI. Although half of these trials demonstrated an impact on adiposity (in regard to skinfolds, but not BMI), all of these interventions targeted multiple dietary changes, and some also aimed to alter physical activity, making it impossible to determine the independent effect of sugar intake on adiposity. It appears that a reduction in sugar intake can be part of an effective strategy to prevent increases in adiposity, but interventions reported to date have been largely ineffective in reducing sugar intake.