Effects of Dietary Fiber Intake on Body Weight and Waist Circumference

Abstract

Aim: Obesity levels dramatically increased in the last decade in UAE. Diets high in energy, saturated fatty acids, low intake of fruits and vegetables as well as inactivity have been found to promote overweight and obesity. A diet high in fiber has been suggested to improve weight loss and decrease other anthropometrical indices. The purpose of this study was to assess the effect of a diet high in fiber on body weight, BMI, and waist circumference (WC).
Methods: One hundred forty overweight/obese subjects aged from 20-30 years old participated in the study. Body weight (BW), body mass index (BMI) and waist circumference (WC) was measured after one month period in which the subjects consumed diet high in dietary fiber (38 g/d/men, 25 g/d/women). SPSS was used for the analysis of data and statistically significant difference was set at P
> 0.05.
Results: BW, BMI and WC were clinically reduced before and after intervention in both males and females. However, these changes were not statistically significant. Percent changes on BW for female and male subjects were 1.45 (95%CI: -12.68, 15.58), P > 0.05 and 1.12 (95% CI: -13.58, 15.82), P > 0.05, respectively.
Conclusion: The high fiber diet did not significantly reduce body weight and WC. Even though there was a small clinically reduction on BW, BMI and WC, however this was not statistically significant. The results, even though were not supportive, they should not discourage people from consuming foods high in fiber, due to other beneficial effects in their health such as decreasing the risk of cancer, lipidemia, type 2 diabetes and metabolic syndrome.

Full text

Arab Journal of Nutrition and Exercise
Volume 1, Issue no. 1, DOI 10.18502/ajne.v1i2.1225
Production and Hosting by Knowledge E
Research Article
Effects of Dietary Fiber Intake on Body Weight
and Waist Circumference
Eiman Al Hammadi
Department of Natural Sciences and Public Health, Zayed University, Abudhabi, UAE
Abstract
Aim: Obesity levels dramatically increased in the last decade in UAE. Diets high in
energy, saturated fatty acids, low intake of fruits and vegetables as well as inactivity
have been found to promote overweight and obesity. A diet high in fiber has been
suggested to improve weight loss and decrease other anthropometrical indices. The
purpose of this study was to assess the effect of a diet high in fiber on body weight,
BMI, and waist circumference (WC).
Methods: One hundred forty overweight/obese subjects aged from 20-30 years old
participated in the study. Body weight (BW), body mass index (BMI) and waist
circumference (WC) was measured after one month period in which the subjects
consumed diet high in dietary fiber (38 g/d/men, 25 g/d/women). SPSS was used
for the analysis of data and statistically significant difference was set at P >0.05.
Results: BW, BMI and WC were clinically reduced before and after intervention in both
males and females. However, these changes were not statistically significant. Percent
changes on BW for female and male subjects were 1.45 (95%CI: -12.68, 15.58), P >
0.05 and 1.12 (95% CI: -13.58, 15.82), P >0.05, respectively.
Conclusion: The high fiber diet did not significantly reduce body weight and WC. Even
though there was a small clinically reduction on BW, BMI and WC, however this was
not statistically significant. The results, even though were not supportive, they should
not discourage people from consuming foods high in fiber, due to other beneficial
effects in their health such as decreasing the risk of cancer, lipidemia, type 2 diabetes
and metabolic syndrome.
Keywords: Dietary fiber; weight loss; body mass index; waist circumference
1. Introduction
The problem of overweight and obesity have gone to high proportions globally, besides
one of the reasons is adoption of a westernized lifestyle, intake of excessive food and
inadequate physical activity are common characteristics of this life style [1]. References
in the last two decades indicate that obesity has reached to double in USA, and now
30% of the US adult population is classified as obese, while the overweight people
How to cite this article:Eiman Al Hammadi, (2017) “Effects of Dietary Fiber Intake on Body Weight and Waist Circumference,” Arab Journal of
Nutrition and Exercise, vol. 1 (2017), issue no. 1, 77–84. DOI 10.18502/ajne.v1i2.1225 Page 77
Corresponding Author: Eiman
Al Hammadi; email: eimanal-
hammadi@hotmail.com
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Eiman Al Hammadi. This
article is distributed under
the terms of the Creative
Commons Attribution
License, which permits
unrestricted use and
redistribution provided that
the original author and
source are credited.
Editor-in-Chief:
Dr. Dimitrios Papandreou
Official Publication of Zayed
University, UAE

Arab Journal of Nutrition and Exercise Production and Hosting by Knowledge E
are reaching the 35%. Pediatric obesity is also an increasing problem with about 16%
being overweight and an additional 15% are at risk of overweight [2].
In addition, increased levels of obesity and low physical activity has been noted
during these decades, with shocking increases in prevalence of type 2 diabetes. The
number of the total adults with diabetes type 2 is expected to be doubled between
2000 and 2030 [2].
The prevalence of obesity is high in industrialized societies. According to research
report by CDC [3] “more than one-third of U.S. adults (34.9%) are obese while the
annual medical cost of obesity in the U.S. is $147 billion” [3].
A report published by the Gulf News (July, 2012) referring to BMC Public Health
journal published in the health journal warned that the world’s adult population is
getting fatter rapidly. 17 million tones of total population weight are due to people
being overweight [4].
UAE Ministry of Health had warned that more people are dying of
non-communicable diseases such high blood pressure, diabetic and heart failure. The
ministry alarmed that children are less physically active today which will make popu-
lation obese by the year 2015. According to the ministry sources about 44.5 % of the
women in the UAE could become obese in coming years if it goes on the same rate as
today [5].
In UAE obesity is not only a problem in women and men but this is increasing in
children also. One of the common reasons of obesity in children UAE is changing eating
habits revealed in their research that the influx of the Western lifestyle [6]. This life
style has resulted in changes in both behavioral patterns and food consumption habits.
The traditional style of eating and foods such as milk, dates and porridge is being
replaced by processed foods such as soda, high sugar, and high fat foods items [7].
Dietary fiber can be metabolized by the gut micro biota to promote the growth of
beneficial bacteria in the gut. Increased consumption of dietary fiber and whole grains
is helpful in normalizing the symbiosis of the gut micro biota and can improve gut micro
biota interactions in obesity and other metabolic diseases. There are differing impacts
on the gut micro biota because of the diverse compositions and structures of dietary
fibers and whole grains [8], some of the dietary fibers may be more beneficial against
obesity than others [9].
One of the beneficial effects of fiber is to promote satiety by decreasing food intake,
and also inhibits fat deposition by removing them through bile production and stool.
The recommended daily intake of fiber for healthy adults is between 20 and 35 g/d
[10].
Dietary fiber intake is been found to help control KCal intake as well as to reduce
the risk of weight gain leading to overweight and obesity. The role of dietary fiber in
energy intake is directly connected to the development of overweight and obesity and
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it’s related to any chemical and physical properties that are connected to the satiety
signal in the brain (Rolls, 1987).
The main purpose of the this study is to identify the relationship between fiber
intake and obesity by examining the effects of a high fiber diet with other anthropo-
metrical parameters such as BW, BMI and WC in 140 adults aged 20-30 years old.
2. Methodology
The study included 140 subjects (63 males and 77 females) randomly selected, aged
20-30 years old from the general population of Abu Dhabi. The study took place from
Jan 2014 to May 2014. Participants with any acute or chronic disease were excluded
from the study. Subjects signed a consent form and the study was approved by the
ethical committee of Zayed University.
Height and weight measured by using the digital/calibrated physician scales to the
nearest 0.1 cm and 100 gr, respectively. Waist circumference measured with a regulated
tape to the nearest 0.1 cm. BMI was calculated by the standard formula: weight(kg)/
height(m)2. Participants were asked to consume their usual daily calorie intake and
food meals and just add/or replace choices of food with high in dietary fiber (25 gr
/day/women and 38gr /day/men) from a list that was given to them for a period of 1
month period. A brochure (appendix 1) was given to each person to explain the amount
and types of foods high in fiber. Data were analyzed using Microsoft EXCEL program
and SPSS program. Statistically significant difference was set at P <0.05.
3. Results
Table 1 displays the main characteristics of the women subjects before and after fiber
intervention. A clinical small reduction was noted for body weight BMI and WC. How-
ever these changes were not significantly important.
Similarly, Table 2 shows the changes for male subjects. The mean and SD for weight,
BMI, and waist for men before and after changes their diet. The weight mean before
was 98.64 and it decreased to 97.54 and SD was 14.13 and declined to 14.61. The waist
mean reduced by 0.28 and SD decreased by 0.22 from (mean ±SD) 96.4 ±6.93 to
96.12 ±6.71.
The Z test was used for analysis of pre and post intervention data for both females
and males. The independent sample z test was used for comparison the results
between the intervention of before and after one month of high intake of Fiber in
the same group of female and male.
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Parameter Minimum Maximum Mean SD Z Value P value
Age (year) Before 20 30 24.77 2.75 - -
After 20 30 24.77 2.75
Height Before 153 174 162.78 3.88 - -
After 153 174 162.78 3.88
Weight Before 65.5 126 88.27 14.13 0.5607
After 63.9 123.6 87 13.98 0.575
BMI Before 25 47 33.35 5.5 0.5332
After 24 46 32.88 5.44 0.5939
Waist Before 80 111 94.05 7.28 0.2335
After 80 110 93.78 7.07 0.81537
T 1: Characteristics of female subjects (n = 77) before and after intervention.
Parameter Minimum Maximum Mean SD Z Value P value
Age (year) Before 20 30 25.57 3.25 - -
After 20 30 25.57 3.25
Height Before 165 184 175.59 4.15 - -
After 165 184 175.59 4.15
Weight Before 79.2 143 98.64 14.7 0.4213
After 77.8 140 97.54 14.61 0.6735
BMI Before 25 48 32.06 5.12 0.3966
After 25 47 31.7 5.07 0.6917
Waist Before 85 119 96.4 6.93 0.2303
After 85 117 96.12 6.71 0.8179
T 2: Characteristics of Male subjects (n = 63) before and after intervention.
Mean Mean
difference%
95% Cl (LL,UL) SD
Weight Before 88.27 1.45 (-12.68),15.58 14.13
After 87 (-12.53),15.43 13.98
BMI Before 33.35 1.42 (-4.08),7.81 5.5
After 32.88 (-4.02),6.86 5.44
Waist Before 94.05 0.29 (-6.99), 7.57 7.28
After 93.78 (-6.78),7.36 7.07
T 3: % Changes on Body Weight among Female.
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Mean Mean
difference%
95% Cl (LL,UL) SD
Weight Before 98.64 1.12 (-13.58),15.82 14.7
After 97.54 (-13.49),15.73 14.61
BMI Before 32.04 1.07 (-4.05),6.19 5.12
After 31.7 (-4.00),6.14 5.07
Waist Before 96.4 0.29 (-6.64), 7.22 6.93
After 96.12 (-6.42),7.00 6.71
T 4: % Changes on Body Weight among Male.
A small reduction is observed in weight of females as shown in (Table 3) by 1.45%
from (mean ±SD) 88.27 ±14.13 to 87.00 ±13.98, (95% CI: -12.68 to 15.98; where the
value of P is >than 0.05 so the result is not significant. And, BMI also reduced as shown
(Table 3) by 0.29% from (mean ±SD) 33.35 ±5.5 to 32.88 ±5.44.
A small drop was also observed for males in weight as shown in (Table 4) by 1.12%
from (mean ±SD) 98.64 ±14.7 to 97.54 ±14.61, (95% CI: -13.58 to 15.82; where the
value of P >0.05 so the result is not significant), as wall as for BMI as observed (in the
Table 4) by 1.07% from (mean ±SD) 32.04 ±5.12 to 31.70 ±5.07. Where the value of
p, the result is not significant at p >than 0.05
A small decrease in waist as shown (in Table 4) by 0.29% from (mean ±SD) 96.4
±6.93 (95% CI: (-6.34), to 7.22, where the value of p >0.05. So the null hypothesis is
rejected.
4. Discussion
The results show that the intake of 25 g/ day fiber for women and 38 g/ day for
men during one month resulted in insignificant weight, BMI, and waist percentage
reduction (P >0.05). Fiber is always associated inversely with body fat and body
weight. Furthermore, fiber intake is also inversely associated with BMI at different
levels of heavy fat intake after collaborating for confounding aspects [12].
In this study 140 participants consumed diet high in dietary fiber and the effects on
weight, BMI, and waist were considered among these participants. There are equivocal
results from previous studies. Body weight reduction is usually described by satiety or
decreased intake of food after eating fibrous food. The results explain that the use
of fiber with vegetables, fruits, whole grains, and legumes, and throughout the life
is considered to be very crucial. There are different mechanisms which have been
suggested in order to make a clear idea about the usage of fiber aids for the purpose
of weight reduction and decreasing absorption of macronutrients. Many mechanisms
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have been suggested for how fiber aids in weight management, decreasing absorption
of macronutrients, including promoting satiation and changing secretion of specific
hormones [13].
The sample was collected from different age groups and examined their food intake
in different time intervals.
The results of study support the fat mass regulation and body weight, which are
produced due to interplay of different factors which includes peripheral sensation
stimuli, central nervous circuits, chemical and mechanical satiation signals rising in the
afferent vagal input and tract of gastrointestinal. The study focuses on the trend of
obesity in different age groups [13].
Another study shows that today’s diet has changed as it is becoming more common,
for example, food from takeaway establishments; also, the intake of high-fat products,
and animal calorie sweeteners with low consumption of fiber from fruits, vegetables or
whole grains creating a substantial problem. Obesity is the balance between excessive
food energy intake and expenditure, from infromation above, the only way to prevent
or treat obesity is to reduce caloric intake and increases energy expenditure through
physical activity. It decreases the size of portions at each meal as an X variable and
increase physical activity as a variable Y to make the equation lean more towards a
healthy life [14].
Another study, in support of this study results shows that the dietary fiber food or
is a powerful ally to prevent or tackle obesity. One of the recommendations made
in relation to the daily diet, is precisely replace foods high in fat and sugar for those
high in dietary fiber, which are obtained from the consumption of whole fruits, leafy
vegetables, whole grains, beans unstrained and meats. Foods high in fiber also have
the ability to hold water and require more chewing and salivation, which is why they
cause satiety The fiber produces a reduction of gastric emptying and delayed so desires
to consume food [15].
According to one more study, it is recommended to consume daily foods rich in
dietary fiber, distributed in different meals, with the ingestion of fruits and vegetables
along with their skins, where possible, because it is where the greatest amount of
fiber is stored, and also consume citrus fruits with skins and/or take the juices without
straining [16].
Limitation of the study included the short time period for the intervention as well as
the absence of additional information of the subjects such as genetics, dietary habits
and physical activity levels. Nevertheless, this study may have some future clinical
benefits in Body Weight and Waist Circumference reduction when a high fiber diet is
consumed.
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5. Conclusions
Even though there was no statistically significantly difference between a high fiber
diet and Body Weight, BMI and Wiast Circumference, the small clinical decreases in
those parameters may be a promising future indication to continue consuming a diet
high in fiber. Additionally, people will continue benefit of consuming a diet high in
fiber in order to avoid future medical health problems, such as, cancer, diabetes type
2, cardiovascular diseases and metabolic syndrome.
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