Obesity: An overview
For a majority of Natural Muscle readers, New Year is no different to any other time of year. With continual setting and reassessing of goals, there is no specific need to make resolutions or to make radical changes. However, Natural Muscle readers are in the minority. At this time of year, with many feeling guilty about Christmas over-indulgence, many people are focused on fat loss (well, focussed for now at least!).
Below is some general information on obesity that, while not pertaining to the typical forum member, may reinforce a few points to family, friends and work colleagues. The intention is to help retain their focus and motivation for a little longer than the typical first fortnight in January.
Prevalence of obesity
When looking at the general population, it’s easy to see why fat loss is a main goal. Without doubt, obesity is a problem – both nationally and internationally. In 2003, 1.7 billion people were estimated to be overweight or obese according to Professor Philip James, the chair of the International Obesity Taskforce. The 2004 Health Survey for England (NHS, 2004) showed that one in four adults are now obese; this showed a sharp rise from 1993 when 13% males and 16% females were classified as obese. Obesity is the second leading cause of preventable death in the United States with 300,000 deaths yearly (Wadden, 2004). Metabolic Syndrome, Diabetes and Hypertension are just a few examples of preventable diseases that can be a direct result of obesity.
Obesity can be defined as “a condition of abnormal or excessive fat accumulation in adipose tissue, to the extent that health may be impaired (Garrow, 1998).” The standard measure for obesity, and advocated by the World Health Organisation (WHO), is Body Mass Index (BMI). BMI is calculated by dividing bodyweight in kilograms by the square of the height in metres. A BMI above 25kg/m2 is considered overweight; obese is defined as 30kg/m2 by WHO (class 1 obesity is 30-34.9 and class 2 35-39.9). Class 3 obesity is a BMI of 40kg/m2 or above.
For many bodybuilders and strength trainers, BMI isn’t a particularly relevant measure of ‘fatness.’ The increased muscle mass skews the results somewhat. Kopelman (2003) suggests that the main limitation of BMI is the lack of differentiation between fat mass and lean mass. Someone with above average levels of muscle may be heavier and classified as obese when all other measures, such as body fat percentage, waist circumference and waist to hip ratio, may be in a ‘healthy’ low-risk range. If you’re striving for fat loss and are new to resistance training, it would be prudent to consider these other measures as relying on BMI could end up being misleading.
Causes of obesity
Obesity doesn’t occur overnight, but is due to energy intake being greater than energy expenditure over a prolonged period of time.
Over time, energy intake has been steadily increasing; the Centre for Disease control and Prevention (McArdle, Katch & Katch, 2007) found that over a 30 year period from 1970-2000, energy intake per day increased by 335 calories in women and 168 calories in men. To many, this may seem insignificant but over a year it equates to an additional 122,275 calories for women and 61,320 calories for men. Both fast food and sugary beverages have been suggested as main reasons for an increase in typical calorie intake.
One aspect of obesity that many seem to disagree on is the genetic element. Bouchard et al (1990) studied the response to overfeeding (1000kcal) on 12 pairs of identical twins. Weight gain ranged from 4.3kg to 13.3kg. Within pair similarities were striking when measuring visceral fat storage compared to a large variance between pairs of twins. This led Bouchard to conclude, that genetic factors explained the weight gain, although no specific factors were identified.
Energy intake is one side of the obesity equation, but the other is energy expenditure. Physical activity levels, and therefore calorie expenditure, are decreasing and this reduction is contributing to the obesity epidemic (WHO, 2000). A study by the European Commission (2003) found that 60% of Europeans had no vigorous physical activity in a typical week, and 40% did not have moderate physical activity. This has resulted in a reduction in energy levels of 800 calories (UK Health Select Committee, 2004).
Diet and exercise
Many factors have been associated with increased obesity: diet, physical activity level, ethnicity, gender, socio-economic status, genetics, leptin levels, etc. For the average person, only two of the above are of relevance; people can only affect what is in their control, namely diet and exercise. Both a healthy balanced diet and increased physical activity levels have been shown to improve the risk of obesity –this isn’t surprising when taking into consideration that the accumulation of body fat is strongly linked to energy balance, controlling energy intake and increasing energy expenditure.
Recent surveys have suggested that a majority of people looking to lose weight as a new year’s resolution want to achieve it without the use of exercise. However, a combination of diet and exercise is the most effective fat loss strategy. Ross et al (2000) compared diet and diet with exercise induced weight loss and found that fat mass was reduced significantly through an exercise intervention. While this is hardly news to the average Natural Muscle reader, many people try to achieve fat loss via diet alone.
Recently, the type of exercise that is best for fat loss has received a lot of attention. For the average person, that probably overcomplicates things a bit. Undoubtedly, research on different exercise intensities shows different rates of fat burning and different amounts of calories expenditure – however, they all had a common theme: fat burning increased, calories expenditure increased and body fat reduced.
As an example, Mulla, Simonsen and Bulow (2000) demonstrated that abdominal fat loss activity was increased during and after exercise at two different intensities.
Diet wise, many companies are looking to take cash from the vulnerable at this time of year. Many people with low self-esteem are looking for a miracle diet. Unfortunately, they don’t exist. Any diet promising dramatic life-changing results is one to avoid. Any diet that suggests eliminating whole food is one to avoid. The main consideration should be sustainability – if you look at a diet and think it can only be followed for 1-2 weeks (or worse, the diet is only recommended for 1-2 weeks), it’s nothing more than short term starvation. To make dramatic changes, consistency with both diet and exercise is vital.
The take home message is simple: don’t be another statistic. Obesity is a leading preventable cause of death and should be manageable through sensible food choices accompanied with regular exercise.
Bouchard C, Tremblay A, Després JP, Nadeau A, Lupien PJ, Theriault G, Dussault J, Mooriani S, Pinault S & Fournier G. (1990) The response to long-term overfeeding in identical twins. New England Journal of Medicine, 322, 1477–1482.
Garrow JS. (1988) Obesity and related diseases. London, Churchill Livingstone.
Kopelman PG. (2003) The management of obesity and related disorders. Taylor & Francis.
McArdle WD, Katch FI & Katch VL. (2007) Exercise Physiology: Energy, Nutrition and Human Performance. Williams & Wilkins.
Mulla NAL, Simonsen L & Bulow J. (2000) Post exercise adipose tissue and skeletal muscle lipid metabolism in humans: the effects of exercise intensity. The Journal of Physiology, 524, 919-928.
NHS (2004) Health Survey for England. Updating of trend tables to include child obesity data. Available: http://www.ic.nhs.uk/pubs/hsechildobesityupdate
Ross R, Dagnone D, Jones PJ, Smith H, Paddags A, Hudson R & Janssen I. (2000) Reduction in obesity and related comorbid conditions after diet induced weight loss or exercise induced weight loss in men. A randomised controlled trial. Annals of Internal Medicine, 133, 92-103.
UK Health Select Committee Report on Obesity (2004) Obesity: Third Report of Session 2003-4.
Wadden TA. (2004) Testimony of the North American Association for the study of obesity.
World Health Organisation. (2000) Obesity : Preventing and Managing the Global Epidemic : Report of a WHO ConsultationTechnical Report Series 894. Geneva WHO.