Rajiv Gandhi University of Health Sciences s61
caloric diet in obese women
SUBMISSION OF SYNOPSIS FOR THE REGISTRATION OF THE DISSERTATION FOR MASTER OF
PHYSIOTHERAPY
SUBMITTED TO
RAJIV GANDHI UNIVERSITY OF HEALTH SCIENCES
BANGaLORE, KARNATAKA
SUBMITTED BY
LEISHANGTHEM SUMILA CHANU
NAVODAYA COLLEGE OF PHYSIOTHERAPY
P.B.No. 26, MANTRALAYAM ROAD, RAICHUR
KARNATAKA
APRIL 2010
RAJIV GANDHI UNIVERSITY OF HEALTH SCIENCES
BANGaLORE, KARNATAKA
ANNEXURE-II
proforma for the registration of subject of dissertation
1. / name of the candidate and address: / leishangthem sumila chanu navodaya college of physiotherapy, mantralayam road, raichur. karnataka.2. / name of the institution: / navodaya college of physiotherapy,mantralayam road, raichur. karnataka.
3. / course of study and subject: / master of physiotherapy (mpt) physiotherapy in cardio-respiratory disorders
4. / date of admission to course: / 25TH MAY 2010
5. / title of the topic:
“a comparative study to analyze the effect of short-term aerobic exercise VERSUS low caloric diet in obese women”
6. / RESEARCH QUESTION
Is there a difference in Body composition between experimental group after short-term Aerobic exercise with Low caloric diet and control group with Low caloric diet alone ?
6.1 / BRIEF RESUME OF THE INTENDED WORK
Obesity is referred to an excess of body fat, that frequently results in a significant impairment of health, when the size or number of fat cells in a persons body increases(20) . Obesity is increasingly common among younger and younger people and so are related disorders and risk. This is becoming an epidemic in western countries and is the reason why it is exceedingly important to develop effective lifestyle strategies and practices to tackle this syndrome and premature mortality risk it causes(4)(7)(33) .
Before 20th century obesity was rare(31) , in the US, obesity among adults and children and have increased markedly since 1980(22). In 1997 the World Health Organization (WHO) formally recognized obesity as a global epidemic(31) . In 2003 – 2004, 32.9% of adults (age 20 – 74 years old) were obese and more than 17% teenagers (age 12 – 19 years) were overweight(22). As 2005 the World Health Organization estimates that at least 400 million adults (9.8) are obese with higher rates among women than men. The rate of obesity also increases with age.(31)
Obesity is caused by the excessive dietary calories, lack of physical activity, lack of sleep, endocrine disorders, medication or psychiatric illness(27). Obese individuals are at increased risk for coronary heart disease, diabetes, high blood pressure, lower back problems and joints disorders.
Excessive dietary calories leads to obesity as extra food turns to fat and store in body. Lack of physical activity can store of more energy, when energy is not exerted and causes the body to naturally deposit fat throughout the body. Lack of sleep can cause change in complex metabolic pathways that control appetite, food intake and energy expenditure(6).
The mutation of a gene called obese, or simply ob, may disrupt hormonal signals that regulate metabolism, fat storage and appetite, which tips the energy balance toward body fat accumulation(37).
Ob gene normally becomes activated in adipose tissue, where it encodes and stimulates production of a body fat signaling and the hormone like protein (ob protein or leptin), which then enters the bloodstream(24). This satiety signal molecule travels to the ventromedial nucleus, the hypothalamic area that controls appetite and metabolism. Impaired ob gene results either excessive hunger drive or loss of appetite. Leptin may affect certain neurons in the hypothalamus in a way to (1) stimulate production of chemicals that suppress appetite and (2) reduce the levels of brain chemicals stimulate appetite(18). These mechanisms would explain how body fat could remain intimately "connected" via a physiologic pathway to the brain for energy regulation.
The proponent of a set point theory, maintain that all persons (fat or thin) have a well regulated internal control mechanism located deep within the lateral hypothalamus that maintains with relative case of preset level of body weight and/or body fat within a tight range(9). Exercise and drugs (eg. fenfluramine, amphetamine and nicotine) may lower a person's set point , whereas dieting exerts no effect.
Obesity is assessed by using the anthropometric techniques. Anthropometric techniques are used to assess growth and development in infants, children, and adolescents include length, height, weight, weight-for-length and head circumference.
It is also used for adults to measure height, weight, BMI, waist to hip ratio and percentage of body fat(8).
Body weight (kg) is measured by using standardized weighing machine,waist circumference measurement (cm) by using the inch tape and body mass index (BMI) is measured by using standardized formula. (BMI=weight (kg)/height (m2).
Obesity can be treated by medications, exercises and diet. Exercise and dieting plays major role in reducing the obesity. Traditionaly aerobic exercise have been prescribed to reduce weight by exercise physiologists and practitioners.
Aerobic exercise training is an augmentation of energy utilization of the muscle by means of an exercise program. Specific aerobic exercises such as cycling, treadmill running , walking and jogging are proven to be effective in reducing the obesity. Training is dependent on sufficient intensity, duration and frequency.
Aerobic exercises decreases sympathetic drive, levels of nor-epinephrine and epinephrine, reduces peripheral vascular resistance and systolic blood pressure. Further it increases myocardial contractility and cardiac output which are due to increase stroke volume. The greater VO2max results in a greater alveolar-capillary surface area, which increases maximal minute ventilation, and ventilator efficiency. The effect of aerobic exercise over the body increases capillary density, muscle hypertrophy, muscle myoglobin concentration, increases the rate of O2 transport and glycogen storage in the muscle. And decreases in body fat, blood cholesterol and triglyceride levels(2)(13)(25). Exercise capacity also improves high-density lipoprotein cholesterol (15.6%) and reduces low-density lipoprotein cholesterol ratio (25.9%). These changes are observed at rest and with exercise.
Diet is defined medically as a diet of 800kcal/day or less. A prudent dietary approach to the weight loss unbalance the energy balance equation by reducing energy intake by 500 to 1000 kcal below daily energy expenditure. Diets to promote weight loss are low carbohydrate-ketogenic/high-protein diets and semi-starvation diets (very low calorie diet) (26).
Ketogenic diets emphasize carbohydrate restriction while generally ignoring total calories and diets cholesterol and saturated fat content. This generates excess plasma ketone bodies-by-products of complete fat breakdown from inadequate carbohydrate catabolism – which supposedly suppress appetite. The ketones lost in the urine represent unused energy that should further facilitate weight loss.
The calories lost by urinary ketone excretion probably equal only 100 to 150 kcal/day(3). This would account for a small weight loss. Low – carbohydrate intake also sets the stage for a significant loss of lean tissue as the body recruits amino acids from muscle to maintain blood glucose via gluconeogenesis – an undesirable side effect for a diet designed to induce body fat loss.
Very low calorie diet (VLCD) may benefit severe clinical obesity where body fat exceeds 40 to 50% of body mass (1). The diet provides between 400 and 800 kcal daily as high – quality protein foods or liquid meal replacements. For most individuals, semistarvation does not compose an “ultimate diet” or the proper approach to weight control. Because a VLCD provides inadequate carbohydrate, the glycogen – storage depots in the liver and muscles deplete rapidly.
Significant lean tissue loss occurs with dieting alone, particularly in the early phase of a VLCD. Whether one can certainly reduce weight through dieting alone is not studied extensively(19).
Combining regular exercise and a reduced calorie diet provides considerably more flexibility to achieve a negative calorie balance, body fat loss and metabolic benefits than either exercise alone or diet alone(10)(21)(30)(34)(35). Adding exercise to a weight control program facilitates longer term maintenance of fat loss than total reliance on food restriction (15)(16)(23) (26). 30min of moderate exercise performed 3days weekly adds 1050 kcal/weekly to maintain a weight loss.
The benefits of regular exercise to dietary restriction for weight loss, promotes overall size of the energy deficit, facilitates lipid mobilization and oxidation, especially from visceral adipose tissue depots, increases relative body fat loss by preserving fat free body mass that accompanies weight loss, requires less reliance on caloric restriction to create an energy deficit, contributes to long term success of the weight loss effort and provides unique and significant health related benefits (28).
Because of the rising amount of overweight and obesity, as well as, the increased amount of obesity related disorders, it is important to develop effective lifestyle strategies and practices to motivate people to exercise and live healthy life(14).
Hence the present study aims to find the effect of short-term Aerobic exercise versus Low caloric diet in obese women.
6.2 / HYPOTHESIS
NULL HYPOTHESIS (H0)
There will be no significant effect of short-term Aerobic exercise with Low calorie diet (LCD) in altering the Body composition among obese women.
ALTERNATIVE HYPOTHESIS (H1)
There will be significant effect of short-term Aerobic exercise with Low calorie diet (LCD) in altering the Body composition among obese women.
6.3 / REVIEW OF LITERATURE
1. Hagan, R. Donald, James et al.(1986) has conducted a comparative study to find the effects of exercise and calorie restriction for 12 weeks on body composition, maximal aerobic power, serum lipid and lipoprotein in 96 overweight individuals. The dietary regimen consisted of 1,200 kcal/day, while exercise consisted of 5 days/week for 30min of walk/running. There were decreases in total cholesterol, very low density – lipoprotein (VLDL) and triglycerides after weeks 4, 8 and 12. Body weight and fat loss (P>=0.05) in the diet + exercise group were significantly greater than for diet group, both groups significantly greater than exercise and control. Authors have concluded diet + exercise will produce a greater loss of body weight and greater increase in VO2 max compared to diet alone(12).
2. S Shinkai, S. Walanabe. et al.(1993) conducted 12weeks study on 32 subjects who were randomly assigned to aerobic exercise + voluntary food restriction on the body composition, Resting metabolic rate and aerobic fitness of mildly obese middle aged women. The exercise/diet group participated in an aerobic training program, 45 – 60 min a day at 50 – 60% of vo2 max, 3 – 4 days a week and also adopted a self regulated energy deficit relative to predicted energy requirements. After 12weeks exercise intervention the experimental group had shown greater reduce in body mass when compared with the control group. Authors have concluded that aerobic exercise enhances the effect of moderate dietary restriction by augmenting the metabolic activity of lean tissue(29).
3. SB Racette, DA Schoeller et al. (1995) conducted 12weeks study on 23 obese women who were randomly assigned to test benefits of aerobic exercise and dietary carbohydrate on energy expenditure and body composition . Significant effects of aerobic exercise included a greater loss of fat mass (P=0.008) and maintenance of total daily energy expenditure (P=0.004) due to a difference in physical activity (P=0.006). Dieting did not significantly influence the body composition or energy expenditure changes, but a greater weight loss was observed after the low carbohydrate than after the low fat diet. Thus the study concluded that the addition of aerobic exercise to a low energy diet was beneficial in the treatment of moderate obesity(30).
4. KP Kempen, WH Saris, KR Westerterp et al. (1995) conducted 8weeks study on 20 obese women aged 25-50 years were randomly assigned to diet alone or diet and exercise on body mass index and percentage body fat. Diet and exercise resulted in a significantly increased loss of fat mass (P<0.05) and greater energy deficit compared with diet. Thus the study concluded that the addition of moderate exercise to an energy restriction program in obese women has advantages with respect to changes in body composition, energy expenditure and substrate utilization (17).
5. CC Curioni et al. (2005) conducted a randomized clinical trials to assess the effectiveness of dietary interventions and exercise in long term weight loss in overweight and obese people which contain 6 studies included 40 – 127 individuals with a duration included a follow up 1 year. The active intervention period ranged between 10 and 52 weeks across studies. Diet associated with exercise produced a 20% greater than initial weight loss (P=0.063). The combined intervention also resulted in a 20% greater sustained weight loss (P=0.058) after 1 year than diet alone. This study concluded that diet associated with exercise results significant and clinically meaningful initial weight loss(5).
6. Shawk et al. (2006) conducted a randomized control clinical trials to assess exercise as a means of achieving weight loss in people with overweight or obesity, which contain 43 studies included 3476 participants with a duration including follow up period of 3 month or more. When compared with no treatment, exercise resulted in small weight losses across studies. Exercise combined with diet resulted in a greater weight reduction than diet alone. There were significant differences in other outcome measure such as serum lipids, blood pressure and fasting plasma glucose. Thus the study concluded that the researcher support the use of exercise as a weight loss intervention, particularly when combined with dietary changes(32).
7. Hϋlya AKDUR, Nadiye BALOTA et al. (2007) conducted a study on 60 sedentary obese female to examine the effects of three different exercise regimens on physical and physiological fitness parameters were diet and step – aerobic exercise (trice weekly, 1hr period for 10weeks)(n=10), diet and walking exercise (trice weekly, 1hr walk 10 weeks)(n=20) and diet only (n=20). Body weight (P=0.046), BMI (P=0.03), and total cholesterol (P=0.012) changed significantly at the end of the study in step – aerobic exercise and walking exercise groups. It was concluded that step – aerobic exercise with low caloric diet seemed the most effective treatment modality(11).
8. Wu T, Gao X, Van Dam RM. et al. (2009) conducted a randomized controlled trials comparing the effect of diet + exercise interventions Vs diet only interventions on weight loss in obese or overweight adults, which contain 18 studies with a duration including minimum of 6 months. We found that the overall standardized mean differences between diet + exercise interventions and diet only interventions at the end of follow up were – 0.25 (95% confidence interval – 0.36 to – 0.14) with a P – value for heterogeneity of 0.4. Because there were two outcome measurements, weight (kg) and BMI(kgm2). The result was that the pooled weight loss was 1.14 kg or 0.50 kgm2 greater for the diet + exercise group than the diet only group(36).