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How Has Obesity Prevalence Changed over Time?

J.M. Densing
J.M. Densing

Obesity prevalence around the world has been rising over time, with the sharpest increases occurring in the second half of the 20th century and into the early 21st. Prior to this time period, obesity was a rare phenomenon. According to the World Health Organization (WHO), obesity has reached "epidemic proportions" around the globe and is projected to continue rising. The sharp rise in the obesity rate in the majority of developed nations is attributed to the increased consumption of high calorie foods and low levels of physical activity. Due to the health risks associated with obesity, the WHO recommends that countries institute weight management programs.

For the majority of history, obesity was rarely seen; in the last century, however, it has become commonplace. The sharpest increases in obesity prevalence have occurred since the mid 1960s, with the rates in many countries doubling or tripling. In the United States for example, the rate of obesity in adults ages 20 to 74 has risen from 13.4 percent in 1962 to 35 percent in 2006, and with the levels rising even faster in children. The WHO estimates that over 300 million adults are clinically obese, which is defined as having a body mass index (BMI) over 30, and considers the problem to be an epidemic. Increases in obesity prevalence are present in developing nations as well as developed ones, in both rural and urban areas, and across all socioeconomic levels; rates are expected to continue rising unless large percentages of the population make lasting lifestyle changes.

It is estimated that over 300 million adults are clinically obese worldwide.
It is estimated that over 300 million adults are clinically obese worldwide.

Increased obesity prevalence is attributed to two major causes. One is the increased availability and consumption of high calorie foods at all levels of society. As populations worldwide shift to more urban lifestyles and experience rising incomes, foods with high levels of fat and sugar are consumed in larger amounts and displace healthier alternatives. Another cause is less physical activity that has accompanied the spread of technology. Smaller percentages of populations work in jobs that require physical exertion, and leisure activities have shifted to more sedentary forms of relaxation.

Women who have higher than 30 percent body fat are considered obese.
Women who have higher than 30 percent body fat are considered obese.

The increases in obesity prevalence around the world has been accompanied serious health issues. Obesity is associated with significantly higher incidences of medical conditions such as diabetes, osteoarthritis, heart disease, certain cancers, and respiratory difficulties. The rising rates of obesity and related health conditions significantly increases healthcare expenditures worldwide. The WHO recommends that countries make resources available for the medical care of affected individuals. It has also advised nations to implement public policy measures to encourage healthy lifestyles, including increasing the availability of foods with low fat and high fiber, and promoting opportunities for daily exercise.

Discussion Comments

Ana1234

@umbra21 - I think it's greatly tied up with poverty and that's the ultimate solution as well. Obesity isn't all that prevalent among people who have money and leisure time because they can afford to belong to gyms and to eat expensive salads. When you are poor, it's tough to make the choice to buy a salad when they are $7 each and a packet of chips is $2 and you know it will stave off your hunger as you work your second job. It's difficult to avoid fast food when you don't have time to cook for your family.

The reason obesity has suddenly become such an issue is because calories are so much cheaper than they used to be. Nutrition is still expensive though.

If we start to eliminate poverty I think we'll see a large reduction in obesity as well. And I really hope that one day we will reduce poverty or even get rid of it altogether.

umbra21

@clintflint - Well, I don't think it's as simple as people just not having enough willpower. For one thing, that's actually a depressing thought, because it means that there isn't really a good solution for this epidemic. People will continue to have access to a lot of high fat foods and won't have much incentive to exercise that doesn't already exist now.

At best, they'll come up with a pill or something that helps you to thin down, but that kind of thing makes me uneasy because it seems like it's just one step away from malnutrition.

clintflint

I've heard that there are some other theories about why we are suddenly faced with so much obesity. The weirdest one is that it's actually some kind of virus or chemical effecting all mammals, because lab animals have gained weight on average over the same period.

In theory they are going to be fed the same amount of the same kind of food day in and day out so there's no reason for one generation to be fatter than another.

But I do wonder if the kind of food they are eating has changed. Maybe it's because of the types of ingredients in the food, rather than the calorie count on its own? Corn syrup is supposed to be fairly bad for you and I wouldn't be at all surprised if it was in the food they feed to lab animals.

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    • It is estimated that over 300 million adults are clinically obese worldwide.
      By: sunabesyou
      It is estimated that over 300 million adults are clinically obese worldwide.
    • Women who have higher than 30 percent body fat are considered obese.
      By: hartphotography
      Women who have higher than 30 percent body fat are considered obese.
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      Individuals who are considered obese may experience a higher incidence of osteoarthritis.
    • The rise of the obesity rate in developed nations is attributed to high calorie intake, and low levels of physical activity.
      By: olly
      The rise of the obesity rate in developed nations is attributed to high calorie intake, and low levels of physical activity.