Overweight and obesity are defined as abnormal or excessive fat accumulation that may impair health. The prevalence of obesity has risen so dramatically worldwide that the World Health Organization has called it a 'global epidemic'. Singapore is no exception. 10.8% of Singaporeans are now considered obese, compared to only 6.9% in 2004. A sedentary lifestyle and unhealthy diet are to responsible for the rise in obesity rates as the Health Promotion Board (HPB) commented. Initially, obesity was a phenomenon mostly of the west, but with the help of globalization, more people in the east are joining those with higher body fat as well.
A recent study on obesity by the Western Australia (WA) public health department has showed that obesity has overtaken tobacco as the most preventable cause of disease, with 60 % of Australians are overweight or obese. WA health experts have cautioned the data will also be similarly mirrored across the country. The calculation of body mass index (BMI) has also been used in the definition of obesity. The body mass index (BMI) equals a person's weight in kilograms (kg) divided by their height in meters (m) squared. A BMI of 23 or more puts you at greater risk of obesity-related diseases (HPB).
With obesity being a growing problem in society today, it's very interesting to examine what is influencing this trend.
Health Problems of Excess Weight
The primary cause of either obesity or overweight is an energy difference between calories intake on one hand, and calories output on the other hand. The connection between overweight and an increased risk of ill-health is well distinguished. This factors contribute to an increase in obesity: a shift in diet towards increased intake of foods that are high in fat and sugars but low in vitamins, minerals and other micronutrients; a reduce physical activity due to the increasingly sedentary forms of work, changing modes of transportation, and increasing urbanization.
Frequent and easy access to high calorie fast foods and drinks and larger portion sizes also contribute to excess weight. Passive forms of entertainment such as computers and television have increased the amount of time spent in a sitting in a crouch. The increased use of cars has led not only to a decrease in transport-related activity but also to a reduction in access to and the construction of walking and cycling paths. These factors combined with the rapid forms of urbanization have lead to the development of obesity.
People who are either overweight or obese have higher mortality and morbidity rates than healthy weight people. Among these conditions are insulin resistance, type 2 diabetes, coronary heart disease (CHD), gall bladder disease, hypertension and sleep apnea (Driskell, 2007). Obesity can also have psychosocial and psychological consequences (Puhl & Brownell 2003).
Insulin Resistance
Insulin is needed for the transportation of blood glucose into muscle and fat cells. By transporting glucose into cells, insulin keeps the blood glucose levels in the normal range. Insulin resistance is a condition whereby the effectiveness of insulin in transporting glucose into cells is reduced. The pancreas responds to insulin resistance by producing more insulin blood glucose level remains normal, until a stage where the pancreas could no longer producing insulin to keep down the resistance. If this compensatory increase does not occur, blood glucose concentrations increase and type 2 diabetes will soon occur (Dandona, Aljada, & Bandyopadhyay 2003).
Type 2 Diabetes
The relative risk of developing type 2 diabetes increases steeply with increasing BMI. Weight gain is also important in determining risk of diabetes, particularly among those with higher BMI. Abdominal obesity, as measured by waist-to-hip ratio, may be a stronger predictor of diabetes than BMI alone. Subjects in the lowest tertile of waist-to-hip ratio did not have increased risk of developing diabetes, even if they were in the highest BMI tertile. However, in each of the other tertiles of waist-to-hip ratio, increasing BMI was associated with a greater probability of developing diabetes. Notably, the relative risk of developing diabetes was 30 times higher among those with the highest BMI and waist-to-hip ratio compared with those with the lowest waist-to-hip ratio (Pi-Sunyer, 2002).
Coronary Heart Disease
A relationship between obesity and CHD mortality was established in the Nurses' Health Study among women who had never smoked. The relative risk of CHD death increased considerably with an increasing BMI. Women with BMI of above 29 were 4.6 times greater risk than those with women with BMI under 22. In addition, the waist-to-hip ratio was strongly predictive of CHD mortality. Women in the higher percentile who have a high waist-to-hip ratio had a relative risk of CHD death of 8.7 compared with those in the lower percentile (Bray, 2004).
Gall Bladder Disease
An independent relationship between obesity and gallbladder disease was shown. Obese women had a 45% greater risk of hospitalization for gallbladder disease than those with BMI below 25. Among obese women, the risk increased further in relation to BMI; those who were morbidly obese had a relative risk of 2.5. Additionally, women with waist-to-hip ratios in the higher percentile have 2 times higher risk than those in the lower percentile. In men, the relationship between BMI and risk of hospitalization for gallbladder disease was only seen among the morbidly obese group (Everhart, 1993).
Hypertension
Hypertension or high blood pressure is common among obese people. In the Framingham Study, it was explained that a 10% rise in body weight results in a 7mm Hg rise in systolic blood pressure. When compared hypertension between obese to non obese people, the prevalence of obese having hypertension is 2.9 times higher (Diaz, 2002).
Sleep Apnea
Diaz (2002) also observed that men with higher BMI are presented with obstructive sleep apnea. Sleep apnea is associated with neck circumference and other factors used to assess bodily fat. He also mentioned that 50% of patients who have sleep apnea have a high waist-to-hip ratio.
Apart from genetic factors, which are not modifiable, other influences on weight are social, economic and cultural factors and the nature of the physical environment. These tend to affect weight through their interaction with dietary behaviors and patterns of physical activity (Deckelbaum, & Williams, 2001). Obesity is strongly linked with a number of major health risk factors (Mokdad, Ford, Bowman, Dietz, Vinicor, Bales, & Marks, 2003). Among people who are overweight, weight loss can reduce the incidence and severity of some of these conditions, as well as improving cholesterol levels, blood pressure and glycaemic control.
Low carbohydrate, high protein diets
What are they
Low carbohydrate and high protein diets are dietary programs that limit carbohydrate consumption while allowing high intake of protein and fats consumption. It is use mainly for weight control or management of obesity with greater than 1.5g protein per body weight in the general population (Kent, 2006). Often foods high in carbohydrates are limited and replaced with food containing a higher proportion of proteins and fats. A study lead by Volek and Westman (2002) found that people lose more weight on low carbohydrate diets than usual weight loss diet.
The modified Atkins diet (MAD) was created by Kossoff and Dorward (2008) to control children with epilepsy have seen at least a 50% reduction in seizures.
Why they are popular
Who would not want to appear slim and wear clothes that are available on the shelves? However the rate of obesity is rising in the world, despite efforts of public health campaign that it has now become a major public health problem. At present there is no scientific consensus on the optimal dietary approach. The conventional dietary program to weight management which most physicians and dietitians recommended is a high-carbohydrate, low-fat, and energy deficit diet. Low-carbohydrate, high-protein diets are gaining popularity as many diet books begin promoting this, the Atkins diet, which has sold more than 10 million copies (Westman, Phinney, & Volek, 2010).
Suitable for weight loss
A study lead by Foster, Wyatt, Hill, McGuckin, Brill, Mohammed, Szapary, Rader, Edman, and Klein (2003) demonstrate that the low-carbohydrate, high-protein, high-fat Atkins diet produces greater weight loss by approximately 4 percent compared to the conventional high-carbohydrate, low-fat diet for up to six months, however the differences do not continue after 12 months.
By restricting carbohydrates drastically to a mere fraction of that found in the typical American diet, the body goes into a different metabolic state called ketosis, whereby it burns its own fat for fuel. Normally the body burns carbohydrates for fuel -- this is the main source of fuel for your brain, heart ,and many other organs. A person in ketosis is getting energy from ketones, little carbon fragments that are the fuel created by the breakdown of fat stores. When the body is in ketosis, you tend to feel less hungry, and thus you're likely to eat less than you might otherwise. However, ketosis can also cause health problems, such as kidney failure (see below).
As a result, your body changes from a carbohydrate-burning engine into a fat-burning engine. So instead of relying on the carbohydrate-rich items you might typically consume for energy, and leaving your fat stores just where they were before (alas, the hips, belly, and thighs), your fat stores become a primary energy source. The purported result is weight loss.
Long term success
The mechanism responsible for the decreased energy intake induced by a low-carbohydrate diet with unrestricted protein and fat intake is not known but may be related to the monotony or simplicity of the diet, alterations in plasma or central satiety factors, or other factors that affect appetite and dietary adherence (Foster et al., 2003).
t is at risk for heart disease. the plan doesn't permit a high intake of fruits and vegetables, recommended by most nutrition experts because of the numerous documented health benefits from these foods.
* Kidney failure. Consuming too much protein puts a strain on the kidneys, which can make a person susceptible to kidney disease.
* High cholesterol. It is well known that high protein diets (consisting of red meat, whole dairy products, and other high fat foods) are linked to high cholesterol. Studies have linked high cholesterol levels to an increased risk of developing heart disease, stroke, and cancer.
* Osteoporosis and kidney stones. High protein diets have also been shown to cause people to excrete more calcium than normal through their urine. Over a prolonged period of time, this can increase a person's risk of osteoporosis and kidney stones.
* Cancer. One of the reasons high protein diets increase the risks of certain health problems is because of the avoidance of carbohydrate-containing foods and the vitamins, minerals, fiber, and antioxidants they contain. It is therefore important to obtain your protein from a diet rich in whole grains, fruits, and vegetables. Not only are your needs for protein being met, but you are also helping to reduce your risk of developing cancer.
* Unhealthy metabolic state (ketosis). Low-carb diets can cause your body to go into a dangerous metabolic state called ketosis since your body burns fat instead of glucose for energy. During ketosis, the body forms substances known as ketones, which can cause organs to fail and result in gout, kidney stones, or kidney failure. Ketones can also dull a person's appetite, cause nausea and bad breath. Ketosis can be prevented by eating at least 100 grams of carbohydrates a day.
Carbohydrate controlled diets may be associated with increased insulin sensitivity and improved glycemic control. High carbohydrate, low fat diets appear to have a more favorable impact on total and LDL cholesterol, whereas low carbohydrate diets have been shown to significantly decrease triglyceride and increase HDL cholesterol levels in short-term studies.
Conclusion
The approach to address weight control must encompass a wide range of behavioral, social, and environmental factors. For weight loss is to be successful, an interdisciplinary team approach should be employed. The goals for obesity treatment are to decrease body weight by develop supportive eating and physical activity. Low carbohydrate diets may be effective in helping people to lose weight in the short term. Before starting any diet, visit the doctor or nutritionist to determine what approach is right for the individual. Further research need to be done on long term studies to evaluate efficacy, safety, and impact on these diets.
How Do Low-Carb Diets Work?
By restricting carbohydrates drastically to a mere fraction of that found in the typical American diet, the body goes into a different metabolic state called ketosis, whereby it burns its own fat for fuel. Normally the body burns carbohydrates for fuel -- this is the main source of fuel for your brain, heart ,and many other organs. A person in ketosis is getting energy from ketones, little carbon fragments that are the fuel created by the breakdown of fat stores. When the body is in ketosis, you tend to feel less hungry, and thus you're likely to eat less than you might otherwise. However, ketosis can also cause health problems, such as kidney failure (see below).
As a result, your body changes from a carbohydrate-burning engine into a fat-burning engine. So instead of relying on the carbohydrate-rich items you might typically consume for energy, and leaving your fat stores just where they were before (alas, the hips, belly, and thighs), your fat stores become a primary energy source. The purported result is weight loss.
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Obesity in Singapore
http://www.todayonline.com/Singapore/EDC101108-0000070/1-in-10-Singaporeans-are-obese
Obesity in Australia
http://www.globalpost.com/dispatch/asia/100415/obesity-fat-australia
