Levels of obesity in Western countries have risen dramatically over the past few decades, sparking a debate regarding the health risks of such a trend. While scientists have known of the risks a high body fat ratio causes for decades, with evidence shown to link diabetes, high blood pressure, heart disease and strokes with increasing weight, popular movements for 'Fat Acceptance' or 'Health at Every Size' have gained popularity. These groups make the claim that being overweight is not as concerning as experts may state, or that indeed a reduction of weight may even be harmful for some, pointing to the role of genetic factors in weight gain.
Over the past 40 years, American incidences of obesity have risen from 15% to 35%, English rates have risen from around 5% to 25%, with other Western countries following a similar pattern, largely based on an increasingly sedentary lifestyle and a glut of processed and high-caloire diets. All major health research, from the World Health Organization to US Governmental study groups, are united in the belief that this is a health crisis which will become the leading cause of preventable death in future years, with the WHO in 2013 calling on all countries to attempt a 25% reduction in rates or face an unmanageable medical care disaster, and the American Society of Clinical Oncology stating in 2015 that obesity is due to overtake smoking as the leading cause of cancer.
Suggestions that attempts to reverse the trend will produce additional health risks to overweight individuals have been made, with claimants pointing to the negative impact of dieting for an individual, with some evidence supporting extreme cases.
A study by the California University investigated the effects of placing a trial group of 121 overweight women on an extreme starvation diet of 1,200 for a three-week period. The researchers found that levels of the stress hormone cortisol rose in the patients, which has been shown to increase risks to the heart and blood pressure. The researchers, however, also stated that this was an extreme diet, common in style to the rise of "Yo-Yo" dieting, and that a more reasonable diet of around 1,500 would pose no health risks and benefit the patients.
The California study highlights the risks of fad or fashionable diets to individuals. Both extremes of diet, starvation and extreme over-eating, are linked to health problems that could be resolved with a middle-ground of reasonable caloric intake and moderate, sustained exercise. This style of diet, high in vegetables and low in fatty, processed food, is the only method shown to maintain a healthy weight and increased longevity, with fashionable dieting methods shown to cause, over a period of time, a return to overweight status. In a society, however, that is increasingly demanding immediate results and quick-fixes, this consistent and sustained style of diet control is becoming less common.