A report by the World Health Organization (WHO) indicates that obesity is among the 10 preventable health risks across the globe. However, this health risk contributes to 300,000 annual deaths in the United States. Obesity is a health risk that is linked to various disorders such as diabetes, liver disease, hypertension, and hypercholesterolemia (Wilborn et al., 2005, p.4). Generally, the condition is thought to be simply associated with an imbalance between a person's energy intake and expenditure. However, the findings of more researches demonstrate that behavioral, genetic, and physiological factors play a crucial role in the etiology of this health risk. Moreover, exercise and diet are considered as important components that play a crucial role in the prevention and treatment of this health risk as well as its associated disorders like diabetes, heart disease, and hypertension.
This article will begin with an evaluation or overall assessment of overweight and obesity epidemic. The brief assessment will include an overview of the worldwide prevalence of obesity, its societal impact, and etiology. This will be followed with a discussion regarding the risk factors and complications of obesity. In this case, the author will analyze the risk factors and complications based on the conclusion presented by researchers or the utilized research articles. The analysis will be carried out on the basis of the link between risk factors or complications and treatment. The treatment approaches that will be evaluated include traditional diet and exercise approach, moderate protein diet with no exercise, high protein diet with no exercise, moderate protein diet with exercise, and high protein diet with exercise. The final sections will examine the possible benefits of consuming high protein diet and possible adverse effects of high protein diet. The purpose of this literature review is to examine the existing literature as it pertains to the study of high protein diet effects on body composition of overweight and obese men and women with or without exercise.
Overweight and Obesity Epidemic
Overweight and obesity is a global epidemic given that nearly 1.2 billion people in the world are overweight while at least 300 million suffer from obesity. Despite being one of the top 10 most preventable health risks across the globe, obesity results in the death of at least 300,000 people in the United States annually. The severity and impact of obesity is attributed to its link to other disorders such as liver disease, diabetes, and hypertension. While it is thought to be simply associated with imbalance between energy intake and expenditure in a human body, obesity is attributed to other factors like behavioral, genetic, and physiological factors (Wilborn et al., 2005, p.4). It is estimated that the prevalence of obesity in established market economies, particularly Europe, is averagely 15-20% of the population, which demonstrates that the condition is a major health concern worldwide. Apart from its prevalence across the globe, obesity has numerous societal impacts including increased health care costs. Overweight and obesity enhance the risk of various life threatening diseases such as cardiovascular diseases and hypertension. Actually, obesity is considered as a major risk factor for heart diseases because of its adverse effects on the cardiac structure.
Risk Factors and Complications
According to Wilborn et. al. (2005), the imbalance between energy intake and expenditure is the major risk factor for obesity (p.6). The excessive intake of energy nutrients contributes to the increase in the size and number of adipocytes at several lifespan stages. Energy expenditure entails basal metabolic rate, physical activity, and the thermic impact of food. While increased energy expenditure and physical activity prevents and treats this health risk, the suggestion is not usually adhered to, which makes the imbalance energy consumption and expenditure as the major risk factors of obesity. The basal metabolic rate plays a crucial factor in energy expenditure. Morenga, Williams, Brown & Mann (2010), state that increased intake of dietary protein and fiber reduced initiatives as well as metabolic syndrome in overweight women enhances the risk of obesity (p.1327). Recent studies have demonstrated that physiological, genetic, and behavioral factors can become major risk factors for obesity. These factors enhance the risk of obesity by having significant effects on body mass index. Notably, genetic and environmental factors influence eating behavior, which may enhance the risk of this condition since obesity is sometimes brought by increase in portion sizes of foods (Wilborn et al., 2005, p.7). The role of these factors in enhancing the risk of obesity is evident in the fact that significant measures have been undertaken to control energy homeostasis and the increased use of lifestyle intervention programs that include healthy nutritional practices and exercise training (Arciero, 2008, p.757).
The complications attributed to obesity are associated with the other disorders that are associated with it. Generally, obesity is a major risk factor for several chronic health conditions such as hyperlipidemia, cancer, heart disease, hyperinsulinemia, and diabetes (Layman et al., 2005, p.1903). Obesity enhances the risk of cardiovascular diseases like insulin and blood glucose concentrations, blood pressure, and blood lipids. The other complications associated with this health risk include arrhythmias, stroke and peripheral vascular disease, diabetes, gallbladder disease, sudden death, arthritis, sleep disorders, and infertility. Overweight and obese men and women tend to experience numerous difficulties in maintaining energy reduction and dietary fiber intakes at optimal levels. For pregnant women, obesity generates several complications that may result in premature birth or even loss of pregnancy because of the various challenges brought by being overweight.
In response to the overweight and obesity epidemic, the use of higher-protein diets has attracted considerable attention that has contributed to their prevalence in the current health care system and the society. This prevalence has been accompanied by recommendations for treatment of overweight and obese adults through measures that are based on energy balance and lifestyle changes that are geared toward lessening daily energy intake and enhancing physical activity (Layman et al., 2005, p.1903). Based on the findings of these research articles, the major treatment approaches for overweight and obesity include
Traditional diet and Exercise Approach
Diet and exercise are regarded as major components or factors in weight control because of their additive impacts on body composition during weight loss in adults, especially adult women. According Arciero et al. (2008), diet and exercise are important aspects of lifestyle intervention programs, which are regarded as core of obesity treatment and prevention (p.757). However, diet and exercise approach are associated with some controversy regarding the specific combination of diet and exercise that is most effective in dealing with obesity and its associated complications (Arciero et al., 2008, p.758). The use of traditional diet and exercise approach is based on their significance on healthy nutrition and increased physical activity, which enhances the lifestyle intervention programs. Since exercise increases body fat loss and preserve lean mass, the combined result of diet and exercise approach seems to be an additional factor for correcting body composition that is expressed as changes in percentage body fat (Layman et al., 2005, p.1908).
Moderate Protein Diet with No Exercise
Morenga, Williams, Brown & Mann (2010) state that moderate protein diet with no exercise demonstrates a moderate increase in consumption of dietary protein and fiber reduced ways of adiposity and some risk factors linked with metabolic syndrome in overweight women (p.1327). These results were based on a 10-week dietary intervention study conducted on body composition and metabolic risk factors in overweight women. Based on this study, moderate protein diet with no exercise facilitated modest reductions in total body fat, central body fat, and body mass with no reduction of lean mass. However, the reductions take place without particular advice or instruction to lessen energy intake or promote weight loss. Even though reductions in body weight through this treatment approach are small, they contribute to metabolic changes that are likely to translate into clinical benefits (Morenga, Williams, Brown & Mann, 2010, p.1327). Wycherley et al. (2012) concurs with the findings of this research by demonstrating that moderate protein diet with no exercise contributes to moderate weight loss when compared to a high protein intake (p.322). In their analysis, while such approach leads to a daily protein intake, moderate or standardized protein intake with no exercise results in lesser body weight loss as compared to high protein intake. Generally, moderate protein intake enhances regional and total body composition and insulin sensitivity in overweight men and women (Arciero, 2008, p.757).
High Protein Diet with No Exercise
According to Wycherley et al. (2012), a high protein diet with no exercise contributes to a higher weight loss as compared to a moderate or standardized protein intake (p.322). Meckling and Sherfey (2007) agree with these researchers since their study demonstrated that in the absence of exercise, a high protein group achieved a 2.5kg weight loss within a 12-week study as compared to a moderate or lesser protein group (p.750). The differences in the weight loss were observed despite the similarity in the level of energy restriction between the two groups.