Does exercise help you lose weight?
Dr Nick Fuller
Leading Obesity Expert at the University of Sydney and founder of Interval Weight Loss.
It’s no surprise exercise is one of the first things we turn to when we decide it’s time to lose weight.
We readily sign up for that gym membership and commit to extra walks with the dog, believing if we exercise enough, the number on the scales will drop.
Perhaps also unsurprisingly, many of us are disheartened when we follow this routine for months and don’t see any change on the scales. This is why I’m frequently asked: does exercise help you lose weight, or is it just diet?
Like all things related to weight loss, the short answer is: it’s complicated.
What does the research say about exercise and weight?
There have been many studies over the past 70 years examining the role exercise plays in weight management. Recent research on the topic has predominantly found exercise alone has minimal impact on weight loss.
This includes a meta study examining all the relevant studies in the area, which found those who used exercise alone lost minimal weight compared with those who exercised and also reduced their energy intake.
A 2018 study found substantial weight loss was unlikely when participants followed the minimum governing guidelines for physical activity. This prescribes 150 minutes of moderate or 75 minutes of vigorous physical activity each week. The overall volume of exercise had to be significantly above the minimum recommended levels in order to achieve significant weight loss without dieting.
Studies show you need to be doing about 60 minutes of moderate activity per day to achieve significant weight loss.
But before you cancel that gym membership, we also need to consider the substantial body of research confirming it’s vital to focus on exercise as part of any weight loss program.
Exercise helps keep weight off long term
Exercise will improve your body composition and prevent muscle decline. Our metabolic rate – how much energy we burn at rest – is determined by how much muscle and fat we have, and muscle is more metabolically active than fat, meaning it burns more kilojoules.
Relying on diet alone to lose weight will reduce muscle along with body fat, slowing your metabolism. So it’s essential to make sure you’ve incorporated sufficient and appropriate exercise into your weight-loss plan to hold onto your muscle mass stores.
Incorporating strength-building resistance training is also important. This doesn’t mean you need to be in the gym every day. Just two days per week and in the comfort of your own home is perfectly fine.
Research confirms moderate-volume resistance training (three sets of ten repetitions for eight exercises) is just as effective as high-volume resistance training (five sets of ten repetitions for eight exercises) for maintaining lean mass and muscle when you’re following a diet incorporating moderate calorie restriction.
Studies also show physical activity and exercise have a substantial effect in preventing weight regain after weight loss. A longer-term study found those sustaining high exercise levels (expending more than 10,500 kilojoules or 2,500 calories each week, for example by walking 75 minutes per day) maintained a significantly larger weight loss than participants exercising less.
Exercise has overall health benefits
Before you start to see the results of exercise on the scales, you’re almost guaranteed to experience the many physical and mental health benefits that come with exercise.
Even low levels of exercise reduce your chance of developing diseases such as heart disease and type 2 diabetes. Research shows exercise is just as important as weight loss for improving health, because most diabetes and heart disease risk markers associated with obesity can be improved with exercise, even if you don’t lose weight.
A physically active person with obesity can be considered metabolically healthy if they maintain good blood pressure, cholesterol and insulin levels. There is good evidence to show the risk of early death associated with obesity is largely reduced or eliminated by moderate-to-high levels of fitness.
Alongside improving your health, regular exercise has other physical benefits, such as improving strength and mobility. It also reduces stress levels, and even low levels of exercise will prompt a decrease in depressive symptoms, improve mood and promote better sleep.
This, in turn, will help you manage your diet better, with the boost to your mood helping you choose healthier foods and prevent impulsive food choices.
The bottom line?
Exercise will help you lose weight and prevent you putting on weight again – it’s just that it won’t help you achieve your weight loss goals in isolation.
Exercise is one of the key pillars of long-term weight management. It plays an essential role in weight loss and maintenance, as do our diet and sleep choices.
To encourage more exercise, take up something you enjoy. Be sure to include variety, as always doing the same daily routine is a surefire way to get bored and give up.