What is the role of physical activity in weight loss?
To understand why there has been such a significant increase in obesity over the last 35 years Dr Carl Lavie in his excellent book the “Obesity Paradox” searches through government records to unearth same amazing findings.
Since 1865 males have grown about 1.5 BMI points heavier, which translates into an increase of 5 kilograms in weight for a man of average modern height today. In comparison, between 1980–2000 the average male BMI increased by 2.3 BMI points, which translates into an additional 8 kilograms. In other words in the 20 years between 1980-2000 the BMI of men rose 7 times faster than the previous 115 years.
Does this mean that there has also been a dramatic increase in the number of Kcal to match this increase in BMI?
From the US Department of Agriculture records it appears that between 1970- 2003 there has been an increase in calorie consumption by a massive 523 calories per day (1970: 2,234 Kcal to 2003: 2,757 Kcal).
If we were to investigate the break up of these Kcal we find that 292 came from fats, oils, sugars and sweeteners while more grains (refined) made up the additional 188 Kcal).
Between 1977 and 1995 the eating of fast foods increased by 300%. By 1997 obesity rates began to soar from 13% in 1962 to 19% in 1997.
By 2008 obesity rates increased to 38% nationwide. At this time the WHO reported that worldwide there were 1.5 billion people 20 years and older that were overweight, and of those more than 200 million men and 300 million women were obese.
In 2010 the medical costs associated with obesity in the United States rose to $160 billion per year. The average cost per male as a result of obesity was $2,646 per year and for a female was $4,879 per year. If we continue at the same rate by 2030 almost 50% of United States citizens will be obese while an alarming 86% will be overweight.
Since 1945 there has been an abundance of easy to get food and a surge in labour saving devices that have robbed us of the much-needed movement of our grandparents era.
The question is “what is the most powerful factor in obesity epidemic…. Too much food or too little movement.”
Eminent epidemiologists suggest that both these factors have contributed to this epidemic. However, they also suggest that while we know and understand that we are increasingly eating high-energy dense empty caloric foods as equally important is the decrease in our energy expenditure or physical inactivity.
Dr Tim Church, Dr Steven Blair and Dr Ed Archer have reported dramatic decreases in energy expenditure over the past 50 years in occupational activities and household duties. So dramatic have these decreases been that they could almost explain the increase in obesity levels even without considering the increase in caloric intake.
This is heady stuff!!
We know that what we eat is critical to weight loss and that high intensity energy exercise does not always produce the weight loss that we might want.
So does physical activity have a significant role in weight loss?
Physical activity can have a dramatic effect on the prevention of cardiovascular disease, diabetes, metabolic syndrome and cancer etc. even in the absence of weight loss.
Given that if we increase our daily physical activity levels at low to moderate levels of intensity over time we can also see long term dramatic increases in the amount of Kcal we expend.
Sadly many people want rapid weight loss, which we know is very hard to sustain and maintain.
We need to recognise that being more physically active throughout the day in all our daily endeavours is a major component in any long-term weight loss program.
I firmly believe that low to moderate physical activities of daily living (NEPA) is the cornerstone for all long-term weight loss and health improvements. It just needs to be built back into our lifestyle.
Our bodies require frequent and unexpected physical activity to sustain life.
In the event that weight loss does not occur for whatever reason it is also important to recognise the importance of improvements in physical fitness can have on our overall health profile.
Some suggest that the loss of physical fitness can be a much stronger predictor of mortality than weight loss.
In a 2011 study citing information from the famous Aerobics Centre Longitudinal study (commenced in 1970) and using data from its 100,000 participants, researchers reported that a small improvement in physical fitness over a 6 years period (no weight loss) was associated with a 15% reduction in the chance of dying from cardiovascular complications.
We need took at our own lifestyle and select times during the day where we are sitting or inactive and see if we can substitute it with some form of additional physical activity.
We can’t underestimate the importance of lifestyle physical activity in the weight loss journey.
Dr Paul Batman