INTRODUCTION
Obesity is a disorder that increases body fat and predisposes an individual to many health complications and problems like diabetes, heart diseases and high blood pressure . It is acquired, when the consumption of calories over time exceeds their burning. Factors that may influence the occurrence of obesity are lack of physical activity, genetic profile, overeating, consumption of calorie-rich foods.
An individual is considered obese, when his weight is at least 20 % more than it should ideally be and has a body mass index (BMI) is over 30. According to the survey conducted by
National Health and Nutrition in 2009 – 2010, over 35 % adults were regarded as obese .
FACTORS CAUSING OBESITY
Consumption of excessive calories
Increased drinking of sugary drinks is also one of the prime reasons for increased carbohydrate intake of youth in America . One of the major contributors to elevated consumption of carbohydrate and calories is agricultural policies that have rendered staple foods such as corn, rice and wheat in the developed nations cheaper.
Lack of physical activity
With the advent of technology such as computers, televisions, washing machines, people have started living a comparatively more sedentary lifestyle than in the past, contributing to development of obesity .
Genetic Predisposition
A gene called FTO has been associated with development of obesity occurring in every 1 in 6 people that overeat. The individuals that harbor this genetic allele have the inclination to overeat and are addicted to calorie-rich foods and are generally obese. Genome-wide-association analyses have identified nearly nine loci related to Mendelian versions of obesity and approximately 58 loci associated with obesity. Four polygenic genes FTO, MC4R, CTNNBL1 and PCSK1.
For the gene melanocortin-4 receptor (MC4R), over 150 mutations related to loss-of-function have been correlated to monogenic obesity and two unique gain-of-function polymorphic variations V103I and I251L have been correlated to prevention of obesity . Additionally, a single nucleotide polymorphism (SNP) situated in the downstream sequence of MC4R has been linked to an increase in the predisposition to obesity. Researchers have reported associations of SNP MC4R and FTO variants with elevated total and dietary consumption and decrease in the degree of satiety in children and adult populations, increased snacking, reduced satiety
Research also demonstrates the role of genetics in predisposing individuals to response to therapeutic strategies, besides affecting their chances of developing obesity. For example, individuals possessing MC4R or POMC monogenic variations react well to diet with low calories or modifications of diet and exercise therapies, whereas MC4R people are unable to sustain loss of weight after completion of the therapeutic interventions . Association of a polymorphism C825T in the GNB3 gene (guanine nucleotide binding protein beta polypeptide 3) with better responsiveness to the drug sibutramine and consequent weight loss .
TREATMENT
Obesity may be treated using a combination of treatment options like exercise, diet and eight-reducing drugs . Some may also undergo surgeries such as bariatric surgery, which is considered as the most effective treatment strategy, proven to decrease obesity -associated complications such as. Orlistat, which is a saturated version of lipstatin and sibutramine, which is suppressor of reabsorption of serotonin and norepinephrine are drugs that have been extensively used for treatment of obesity .
CONCLUSION
Obesity is a disorder that is characterized by excessive fat in the body and elevates the risk of individuals to several health problems . Sedentary lifestyle, increasing consumption of calories and inherent genetic predisposition are some factors that contribute in the development of obesity . Recent literature has uncovered many genes and related polymorphisms associated with development of obesity and that influence the responsiveness of obese individuals to therapeutic strategies .
References
Choquet, H. M. (2011). Genetics of Obesity: What have we Learned? Curr Genomics, 12(3): 169–179.
medicalnewstoday. (n.d.). Retrieved from medicalnewstoday.com: http://www.medicalnewstoday.com/info/obesity
Obesity. (2014, October 1). Retrieved from Medline Plus: https://www.nlm.nih.gov/medlineplus/obesity.html
Overweight and Obesity Statistics. (2012, October). Retrieved from NAtional Instirute of Diabetes and Digestive and Kidney diseases: http://www.niddk.nih.gov/health-information/health-statistics/Pages/overweight-obesity-statistics.aspx
