New Study Finds Energy Levels Have Dropped Since the 90s

The World Health Organization (WHO) says over 4 million people around the world die from being overweight or obese. With obesity rising across the globe, many wonder if increased food consumption or sedentary behavior is at fault.

A new study led by the University of Aberdeen in Scotland finds that American and European energy levels have declined in the last 30 years. Their discoveries were published in the journal Nature Metabolism on April 26. ​​

Obesity occurs when an individual’s weight is higher than a healthy weight at the person’s height. According to the CDC, the obesity prevalence in the United States was listed as 41.9% from 2017 to March 2020. Obesity is very common among America’s youth, with 14.7 million children and adolescents currently affected by obesity.

Obesity is prominent in the West, with more people obese than underweight in every region except sub-Saharan Africa and Asia, the WHO says. In the United Kingdom, Britain's National Institute for Health and Care Excellence (NICE) says the obesity population has risen from 14.9% in 1993 to 28.0% in 2021. Data collected in 2019 from European Union counties shows 52.7% of citizens living in member states are obese.

Obesity stems from more energy consumed than energy spent. Professor at the University of Aberdeen and study lead, John Speakman, explains the method his global team of investigators performed in a university release.

"We have some evidence that people are becoming more sedentary, especially with a shift from manual to more sedentary occupations — but that is also only an indirect measure of how much energy people are spending," Speakman says.

"There is however a method for directly measuring our energy expenditure called the doubly-labeled water technique, which is a urine test that involves having a person drink water in which the hydrogen and oxygen in the water molecules have been replaced with naturally occurring 'heavy' forms, and then measuring how quickly they’re flushed out."

Speakman and his fellow scientists established a database of measures using the doubly-labeled water technique that featured over 100 studies and 6000 measurements. The International Atomic Energy Agency Doubly Labeled Water database enabled researchers to observe the energy expenditure of 4,799 adults across the U.S. and Europe.

After altering the data for the effects of age and body composition, Speakman and his team found that total energy expenditure has decreased since the early 1990s. Male energy expenditure dropped 7.7%, while females fared slightly better at 5.4%.

Active expenditure involves the amount of energy that a person burns during physical activity and exercise. Resting expenditure refers to the amount of energy a person burns at rest with no physical exertion. Speakman adds that while activity energy expenditure has marginally risen, resting energy expenditure has dropped.

Researchers are currently unable to explain the drop in resting expenditure. Speakman believes our diet may have a role to play.

"We were able to see in mice that the make-up of the fat they ate affected their metabolism, but whether the same effects occur in humans requires verification. This is potentially a very exciting piece of research as if the same effects do occur in humans, it raises the possibility that we may be able to reverse this decline by changing what we eat."

- John Speakman

Steps to increase activity

Exercise is a major proponent of fighting obesity and serves as a way to release potential stressful energy. For adults, it is recommended to participate in physical activity for 150 minutes each week. The CDC suggests 60 minutes of play for children. Research shows increasing physical activity can prevent heart disease, type 2 diabetes, and some forms of cancer.

If you are new to an exercise routine, it is important to start small. Brisk walking, recreational swimming or water aerobics, yoga, and slow dancing are great choices for starters. More intense activities include running, competitive swimming, tough hikes, high-intensity interval training, and other workouts that increase the heart rate faster than slower forms of exercise.