Does exercise actually help you lose weight?

Here's what the science says

Experts have found exercise alone doesn’t cause lasting weight loss. Image: Unsplash

While it's been a long-held belief that setting our alarms and hitting the gym consistently will help shift a few kilos, experts say the reality is a lot more complicated. 

Picture this: You’re absolutely killing it with a new fitness program, getting faster and stronger, noticing greater mental clarity, and a reduction in overall stress. But when you step on the scale, suddenly all those benefits parachute out of your mind leaving you feeling like a failure.

If this sounds hauntingly familiar, you’re in good company. 

Exercise has long been sold to us as a one-way ticket to the body we’ve always dreamed of. But it turns out the science on the subject is, well, a little deflating.

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The nitty gritty 

Weight loss science can be a bit sticky thanks in part to a lack of distinction between weight loss, and lasting weight loss. There are multiple ways to achieve short-term weight loss (juice cleanse, we're looking at you), but what really matters when it comes to our health is what can be sustained over the long term. And in that category, the news is pretty grim. 

“In my experience, exercise alone doesn’t cause lasting weight loss,” confirms sports and exercise scientist Liz Nelson. “Many people who start an exercise regimen without changing their dietary habits with the goal of losing weight may be disappointed to discover that the effects are usually minimal. This could be because we automatically try to achieve homeostasis or balance in our body by increasing energy intake to match the output.”

The science certainly bears this out, with this systematic review of studies (with a minimum of one-year follow-up) suggesting that subjects who used exercise alone for weight reduction experienced minimal weight loss.

This randomised controlled trial published in 2012 also reported very modest differences between movers and non-movers. It looked at the effect of exercising five days a week on over 200 men and women over 12 months. Previously sedentary participants were subject to an hour of vigorous-intensity exercise, six days a week compared with a control group receiving no intervention. The results showed a rather underwhelming difference of around 1-2kg between the exercisers and the control group. Not exactly the kind of large-scale transformation being touted by gyms and fitness studios.

What really matters when it comes to our health is what can be sustained over the long term. Image: Pexels

Dr George Balalis is a bariatric, upper GI and general surgeon based in Adelaide whose work centres around patients who wish to achieve lasting weight loss. He says, “Exercise has little to do with weight management, and this is evident time and time again in the patients I see every day.” Dr Balalis understands that weight is a complex issue, explaining “Body weight is the product of genetic background (DNA), epigenetic effects (heritable traits that do not involve changes in DNA), and the environment and lifestyle factors.

So, it would seem the dominant narrative that exercise leads to weight loss is down to a feat of good marketing, rather than good, solid research. Bummer. 

What about weight maintenance?

We do see some promising data on the use of exercise as a means of limiting weight gain over the long term. This 2014 study from Norway tracked weight and physical activity in 127 participants over a whopping 33 years. It found that men who maintained activity over the general recommended guidelines (more than 150 minutes per week) gained 5.6 kg compared to 9.1 kg in less active men, and 3.8 versus 9.5 kg in women. 

The important thing to note here is that the differences were still modest, and only observed in people exercising well above what the average person can maintain - so not exactly earth-shattering stuff. 

Moving for ‘the right reasons’

OK, but what’s the harm if it gets us moving? Well, just as it is on The Bachelor when it comes to our fitness routine, it’s essential we’re there for the right reasons. 

Because as it turns out, using weight loss as the sole motivator to keep up a healthy fitness routine could be hurting our overall health, and go some way in explaining the high attrition rates enjoyed by a vast majority of gyms and fitness programs.

This research study from 2018 gathered data from 301 rural women about their motivations for weight loss over 30 months. It found that women who were motivated by appearance-based goals were more likely to actually gain weight after the 30-month intervention. This is in contrast with those who were motivated by other reasons, such as improved health, who were found to be more likely to lose or maintain their weight.

In her work as an accredited practising dietitian and credentialled eating disorder clinician, Erin Murnane sees this play out time and again, “From my personal experience working with hundreds of clients over the past ten years, the message that exercise leads to weight loss is incredibly harmful to our health” she shares. “It makes sense that if we exercise for weight loss and don’t see the number we want on the scales, we’re more likely to give up. However, if we continue to focus on the non-appearance-related benefits of exercise, which can be consistent, we’ll be more motivated to continue moving our bodies.”

Exercise has been credited with a reduction in the risk of developing multiple life-limiting diseases. Image: Getty

Shreen El Masry is a body-positive personal trainer, certified intuitive eating counsellor and author of Be You Be Free.  She also sees the harm that can come from moving purely to see our weight drop. “When we exercise purely for weight loss, it can lead to low self-esteem, poorer body image and depressive symptoms,” she explains “It can also demotivate us and give us a negative relationship with exercise.”

The wellness space is awash with marketing jargon dressed up as scientific fact. From pervasive campaigns touting the benefits of colon cleansing or oil pulling, so it’s no wonder we’re confused. 

The good news is, that exercise is the closest thing we have to a magic bullet when it comes to supporting our overall health and wellbeing, so let’s dive into everything it can do for us.

What does exercise do?

It might be quicker to list the things regular physical activity can’t offer us because the list is extensive.

“It doesn’t matter who you ask; it’s a universal fact that exercise is beneficial for our health, physically, mentally and socially,” says Murnane “More specifically, benefits associated with exercise include reduced stress, increased energy, improved sleep, improved self-esteem, and reduced risk of depression. Exercising can also create social connectedness, arguably one of the most influential factors in our overall health and wellbeing.”

Beyond that, exercise has been credited with a reduction in the risk of developing multiple life-limiting diseases such as dementia, heart disease, osteoporosis, and even some cancers. It is recommended as a non-medical treatment for the management of many chronic conditions including osteoarthritis. 

“Exercise has so many amazing benefits that are rarely spoken about,” Says El Masry, “It reduces stress, anxiety, and depression, and improves our blood pressure and cardiovascular fitness. It makes us happier, gives us energy and healthier joints and importantly, helps us live longer. But my favourite benefit of exercise is that it makes you smarter by improving your brain function, especially with learning and memory.”

From her work as an exercise scientist, Nelson reports that exercise also results in “improved physiological markers such as cardiovascular health, improved bone density, improved blood glucose control and reduced risk factors for Type 2 diabetes.”

So if you’ve been hitting the gym, labouring under the false promise of weight loss, know that you are not alone. It’s almost universally accepted that working out makes you thin, so don’t beat yourself up!

While it may feel deflating to learn your daily jog might not help you achieve your aesthetic goals, the benefits it does offer are kind of magical, and knowing this might just be the key to sticking with it. 

Originally published as Does exercise actually help you lose weight?