"Eight in 10 men will be overweight or obese by 2020", "Obesity timebomb: Eight in 10 men will be overweight by 2020" and "80% of men will be overweight by 2020 study claims" in major UK newspapers. It is an impressive report that analyses the most recent Health Survey for England data (1993-2007) and uses this to predict future obesity trends and their consequences in terms of the increase incidence of Body Mass Index (BMI) related diseases. It uses a statistical model to predict the trends for obesity to the year 2050. It looks mainly at an age group of males and females between 40-65, sorts them out according to their BMI and makes the predictions for obesity in relation to other non-communicable diseases such as arthritis, coronary heart disease, diabetes, gall bladder disease, hypertension, stroke and the following cancers: breast,colorectal, endometrial, kidney, oesophageal and liver.
The BIG message being sent to us: the higher BMI, the quicker you will die from one of this non-communicable disease! Looking at this research paper, it is difficult to believe that this kind of extrapolation is being taken as a good predictor for these risks. It is not a statistically significant model and is the equivalent of simply guessing and distorts the outcomes of the true picture. We all know that being overweight or obese increases our risk of non-communicable diseases as we discussed this in our article "Diet and Non-Communicable Diseases" but does this risk also correlate with having a high BMI? BMI was first described by Adolphus Quetelet in the mid 19th century and defined as the weight in kilograms divided by the square of the height in meters. The general acceptable BMI range as defined by the Centre for Disease Control (CDC) and World Health Organization (WHO) for overweight (25 to 29.9) and obesity (30 or more) is based on evidence from studies of morbidity and mortality risk mainly in the younger (18 years old) Caucasian population. Until recently, this gold standard was for everyone, irrespective of age or sex. Recently, it has been proven that for children, BMI (also called BMI-for-age), should be calculated differently. Additionally, BMI ranges for children and teens are defined so that they take into account normal differences in body fat between boys and girls and differences in body fat at various ages. For adults though, there are many other factors in that need to be considered when correlating BMI with obesity especially for the older population. For instance, both smoking and pre-existing illness cause a lower BMI over a period of decades of the adult lifespan, and both predict increased mortality.
The medical community generally agrees that your best weight is a lean body with fat being 10 to 18% of total body weight for men and 18 to 25% of total body weight for women. If you exceed these limits you have too much body fat, regardless of your actual weight. It is possible to be overweight but not having too much fat, especially for those with a large muscle mass from body building or other muscle building exercises. Factors such as fitness, ethnic origin and puberty can alter the relation between BMI and body fatness and must be taken into consideration. A recent study showed that the diagnostic accuracy of BMI to diagnose obesity is limited, particularly for those with BMI of 25 to 30, for men (body builders, athletes) and for the elderly as BMI could not distinguish between fat and preserved lean mass. The authors state "a scenario to exemplify this would be a person with a BMI of 25 with preserved lean mass and mildly increased fat content, compared to another person with the same BMI of 25 with limited lean mass and a high body fat content, both representing completely different levels of exposure to the deleterious effects of adipose tissue, a fact that limits the BMI ability to predict long-term health outcomes." In fact, BMI itself is only a proxy for body fatness; it is only an overall measurement of obesity. Fact: Most heart disease occurs in people who do not show any of the traditional risk factors. Several studies show, conclusively, that for many who are classified as being overweight, even obese, lifespan is not shorter in comparison to "slim people"as this does not make you more prone to strokes, heart disease or cancer. BMI thresholds for overweight and obese are overly restrictive for older people and it was in fact how sedentary these elderly people were that increased or decreased mortality. Furthermore, there is evidence to show that even in young adults, there appears to be an inherent bias of using BMI as an indicator of obesity in diverse men and women. In reality, obesity is a heterogeneous condition with individual differences in the pattern of fat tissue deposition. This is important because fat the accumulates in and around the internal organs known as visceral fat and in particular around the abdominal area, is quite strongly associated with enhanced risk of chronic diseases such as heart disease and type 2 diabetes; while fat under the skin surface (subcutaneous fat) is not directly associated.
A recent study on subjects with a BMI of 30 or above both healthy, showed that about a third of these subjects, although 'obese', did not fulfil the criteria for 'metabolic syndrome' (a term created to identify common atherosclerotic cardiovascular disease risk factors that often cluster together). In other words, these people could be described as being 'metabolically healthy' and this applies to a significant proportion of the population: being 'obese' does not at first sight appear to be such a bad thing in health terms. The authors found that 'obese' but 'metabolically healthy' individuals tended to have less visceral fat, and more subcutaneous fat. This is an expected finding, but also highlights again why the BMI is a quite-useless marker for health. This study also found that those fulfilling the criteria for metabolic syndrome and therefore more likely to have excess visceral fat, also generally had higher levels of the 'inflammatory' substances interleukin-6, tumour necrosis factor-a, and plasminogen activator inhibitor-1. There is emerging evidence that, for whatever reason, visceral fat is associated with or encourages a 'pro-inflammatory' state, and is now quite well established that inflammation is a possible key underlying process in the development of chronic diseases including heart disease and type-2 diabetes. Another recent study conducted mainly on women also had similar findings. Although BMI has traditionally been the chosen method by which to measure body size in epidemiological studies, alternative measures, such as waist circumference, waist:hip ratio and the waist:height and techniques such as ultrasound, computed tomography (CT), and magnetic resonance imaging (MRI) which reflect the amount of fat located in the abdominal areas, have been suggested to be superior to BMI in predicting risk for various obesity-related conditions such as diabetes. Although waist circumference is an easily obtainable index of abdominal adiposity, it does not distinguish between the subcutaneous and visceral adipose tissue compartments. One Framingham Heart Study looked at participants with a volumetric computed tomography (CT) method to define the prevalence of abdominal obesity in terms of elevated volumes of visceral and subcutaneous fat and correlate this to risks of obesity and non-communicable diseases. They found that clinical measures of BMI and waist circumference may misclassify individuals in terms of visceral fat and metabolic risk. In April 2006, researchers at Cedars-Sinai Medical Centre in Los Angeles reported the results of their clinical study of 14,739 patients diagnosed with coronary artery disease who were followed for over three years. They found that obese and overweight patients were at significantly lower risks for cardiac death than normal weight patients. Therefore, combining BMI with other methods such as waist circumferences may be a valid way of assessing risk of obesity and related diseases but even these are biased as waist circumferences cut-points are based on BMI category, hence are interrelated.
Factors such as life style can also affect risk of obesity and related diseases such as ethnicity, exercise and nutrition. Data in women suggest that there may be racial/ethnic differences in visceral abdominal fat at a given BMI or waist circumference and different waist circumference or BMI cut-off points may be necessary to adequately reflect risk in different racial/ethnic groups. Recent evidences suggest that the increasing prevalence of Type II diabetes and cardiovascular disease (CVD) in Asian countries is occurring at levels of BMI much lower than the WHO BMI cut-point of 25. Exercise is a main contributing factor to the amount of visceral fat. Systematic, progressive resistance training - also called strength training- is a safe and efficient way for middle-aged and older adults to improve their health. One large study of 2834 patients ranging from 32 to 83 years done recently by the Farmington Heart Study, found that people who every day eat several servings of whole grains and limit intake of refined grains have less visceral adipose tissue. This study found that while those in the higher whole grain intake only had a 4% lower waist circumference, they had a 17% lower visceral fat tissue than those consuming the lowest whole grain. Interestingly, higher intakes of refined grains were associated with higher visceral fat tissue. This association persisted after the researchers accounted for other lifestyle factors such as smoking, alcohol intake, fruit and vegetable intake, percentage of calories from fat and physical activity. The researchers said "while their study adds to other research that shows a link between higher whole grain intake and reduced risk of metabolic syndrome and insulin resistance, it is, like the others, an observational study, and the numbers are not that high, so really what needs to happen now is more robust, larger studies that specifically investigate whole grain consumption and body fat distribution, in much larger and diverse populations, in order to discover what drives the link." There is much change in the terminology of "fat" itself. It has been common knowledge among basic scientists and clinicians that fat or the adipose tissue is an active endocrine and immune organ with pathogenic potential. As such, clinicians and patients may find the term 'obesity' being relegated to describing fat-mass related pathology. Clinicians may find the term 'metabolic syndrome' replaced with 'adiposopathy' and 'sick fat' as scientific and clinical terms, respectively, which better describe the adverse metabolic consequences of dysfunctional adipocytes and pathogenic adipose tissue. In conclusion, BMI itself is not a perfect measure of body fat and other measurements need to be taken to determine if a person is indeed overweight or obese and further at risk of developing a non communicable disease that will shorten their lifespan. Only time will tell if the report by Professor Klim McPherson might prove to be correct or if we can control our time on this earth by just following a few simple tips. Our advice is to eat wisely especially by eating whole grains and avoiding processed foods, exercise regularly and keep to the agreed best weight with fat being 10 to 18% of total body weight for men and 18 to 25% of total body weight for women.
Our book "Is your Food Killing You?" goes into more detail on how and why your food causes Cancer and Diseases and much more. We pride ourselves on giving you the whole picture and all the facts not just the shocking headlines without any substance behind it. If you want to know more about how your food affects your health then visit Food Myths Busted [http://foodmythsbusted.com/blog]. Find out what the Food and Medical industry does not want you to know as well as why the Government is in on all of this you deserve to know the truth about the food you consume.
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