Diet vs exercise: Which is more important for weight loss?

One is 10 times more influential

• In this article:

• New research reveals exercise may not be as significant in achieving weight loss compared to other factors

• Over-eating and ultra-processed foods could the major culprits behind our rising obesity rates

For as long as we can remember, we’ve been told the formula for achieving healthy weight loss consists of two equal and entirely symbiotic factors: Exercising regularly and eating a healthy diet. But do the two truly yield the same amount of influence over how successful our attempts to lose weight are?

While there’s no denying the importance of regular exercise in maintaining a healthy weight, improving our physical and mental health and warding off the threat of chronic illness, new research published in the journal Proceedings of the National Academy of Sciences has revealed that how we fuel our bodies from a nutritional perspective is definitively more influential in whether our bodies gain or lose substantial weight.

According to the recently published research, the rise of obesity rates around the world fundamentally stems from increased caloric intake and high prevalence of ultra-processed foods, rather than a reduction of energy expenditure or exercise. 

The global study used advanced tracking technologies and data collection to determine the greatest driver of increasing obesity rates across communities around the world. 

Historically, as development and industrialisation increase in communities, physical labour and activity decline significantly. With the exponential rise of obesity mirroring the exponential rise of industrialisation and development around the globe, public health experts have long held the view that the subsequent shift towards more inactive lifestyles is the major driver for the global rise in obesity cases and associated chronic diseases. 

Aiming to challenge the hypothesis that decreased exercise contributes significantly to rising obesity rates, the researchers examined the activity habits of people from all kinds of communities around the world, from industrialised, inner-city populations to more traditional farming and foraging communities. 

Does decreased exercise contribute significantly to rising obesity rates? Image: Pexels

After comparing data from different populations over time, the study found that activity decline did not necessarily cause an increased prevalence of obesity, nor did it always guarantee a reduction in total energy expenditure. 

According to the data, people in highly active communities and those in more sedentary environments burn roughly the same amount of calories, indicating that the human body has the ability to adapt and compensate energy expenditure to whatever lifestyle befalls it. 

So, if activity levels and exercise are less influential to weight loss and management than previously thought, what is driving the global surge in obesity? As confirmed by the study’s comparative analysis, diet – specifically caloric intake and a high reliance on ultra-processed foods – is largely to blame for the rising rates. 

Ultra-processed foods, have been continually associated with wider health issues and an increased risk of chronic disease. Image: Pexels

The findings suggest that while movement is still important for health, calorie intake and food quality have a significantly greater impact on obesity rates. While previously believed to be equally attributed to diet and exercise, the new research suggests that overeating and processed foods are up to 10 times more likely to cause weight gain than reduced activity.

“Our analyses suggest that increased energy intake has been roughly 10 times more important than declining total energy expenditure in driving the modern obesity crisis,” the study authors write.

Ultra-processed foods, which have been continually associated with wider health issues and an increased risk of chronic disease, are also major culprits in the rise in obesity rates worldwide, the research suggests. 

Sugary snacks, fast food and food products deviating from fresh, whole food ingredients are typically high in calories and low in nutritional value, and are packed full of preservatives, sugar and artificial ingredients – AKA a recipe for disastrous weight management. 

Of course, physical activity remains a priority recommendation for people looking to lose weight or maintain good physical fitness, muscle function and general health, but when it comes to tackling obesity, the latest research suggests what you eat – and how much – matters far more. 

Originally published as Diet vs exercise: Which is more important for weight loss?