exercise vs diet on scales

Does Exercise Help You Lose More Weight?

By Tracey Walton wlr team

A hotly debated question, even amongst the best of friends ...

We examine the question in the light of results you may find surprising from new research presented at the ASN annual conference in June 2020.

Researchers from University of Pittsburgh carried out a study which aimed to assess whether including exercise alongside a reduced calorie diet boosted weight loss.

Their conclusion was that exercise brings no significant boost to weight loss compared to diet alone.

The Study

The researchers randomised 383 overweight participants into 3 groups. Each group took part in a behavioural weight loss intervention based on calorie restriction and varying amounts of exercise.

weight loss exercise study diet only group

The diet only group: calories restricted to within 1200-1800 per day, no prescribed exercise

weight loss exercise study moderate exercise group

The moderate exercise group: calories restricted to within 1200-1800 per day, exercise prescribed building to 150 minutes (2½ hours) per week.

weight loss exercise study high exercise group

The high exercise group: calories restricted to within 1200-1800 per day, exercise prescribed building to 250 minutes (just over 4 hours) per week.

The Results

Results recorded at six months and 12 months showed roughly the same amount of weight loss in all the groups.

  • Daily calorie intake decreased by an average of 500 per day across all groups
  • Percent dietary fat intake decreased in all groups
  • Participants' level of physical activity did not affect their ability to keep their calorie and fat consumption within bounds
  • After one year of limiting their intake to 1,200-1,800 calories per day, regardless of the amount of exercise, participants lost a little over 20 pounds on average

So Where Does That Leave Us?

These findings could be a major source of encouragement for people who want to lose weight but can’t do (or hate doing) exercise. We know from experience that many wlr members have reached their weight loss goals without exercise.

But don’t throw your trainers out yet …

There are also lots of members who have found exercise really helps their weight loss, in several ways:

  • They can eat more calories while continuing to lose weight at their target rate of loss – because the exercise means they burn more calories
  • Physical activity makes them feel good and has the knock-on effect of helping them eat better
  • Exercise plays a direct role in reducing belly fat, a near-universal desire amongst people who want to lose weight

It's also the case that many people want to lose weight as part of improving their health. Regular exercise has been proven to preserve and promote better health in hundreds, if not thousands, of peer-reviewed scientific studies.

Unless we take steps (literally) to purposefully keep ourselves fit and active, levels of both fitness and physical activity will increasingly decline over time – along with strength, mobility, and range of movement.

Unanswered Questions and Possible Explanations

The results of this study were reported at the ASN (virtual) conference in June 2020, and there is only an abstract1 and the virtual abstract presentation2 available at the moment. So there may well be more important details to come. (We’ll update as soon as we see them.)

Did Exercisers Eat More Calories?

The calorie limits prescribed to all the groups in the study cover a very wide range from 1200 to 1800 a day. (A difference of 600 calories a day adds up to over a pound a week in weight terms.)

It seems likely that people in the exercise groups naturally consumed more calories each day than non-exercisers - while remaining within the limits set.

Essentially ‘eating back’ calories burned in exercise, therefore maintaining a similar calorie deficit to the non-exercise group.

So was being able to eat more while losing the same amount of weight a benefit to the exercise groups?

How Did Participant’s Body Composition Change?

Our lean to fat ratio is important for weight control in the longer term as well as for general health.

From a weight control point of view, the higher the proportion of muscle in your body the more calories you burn – even when you’re at rest. This is because a pound of muscle burns approximately 4-5 times more calories than a pound of fat3.

Whilst these numbers are not dramatic – around 60 calories a day burned, at rest, per 10lbs of muscle. They add up over time to a slower metabolism that requires fewer calories to maintain.

Not helpful in the context of weight control.

Were Any Other Health Markers Measured?

For many of us losing weight is as much about looking after our health as it is about how we look and feel in our jeans.

We’d like to know if any health markers were measured and what differences there were between groups.

Of course, regular exercise confers its health benefits over many years so would be limited for a one year study, but it would be interesting to see if any early signals were picked up.

Conclusion (for now)

There’s so much evidence showing that exercise is crucial to keeping ourselves healthy, at wlr we always recommend including it if you can – even if it won’t mean you lose more weight or lose weight faster.

We also know that many of our own successful members have found exercise to be a helpful part of their weight loss journey.

Exercise has also been identified as one of six key factors for successful weight loss maintenance.

You can lose weight without exercise, and lots of people on wlr do. But we’d suggest you’ll enjoy the journey more, and find weight loss more sustainable, if you include a regular dose of exercise.

Lose Weight With or Without Exercise

It’s all about calorie balance. You can use the tools in wlr to make sure you’re getting the number of calories you need for healthy weight loss. Try it free to get your numbers and your body into shape

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References & Other Helpful Resources

1) Carli Liguori, Renee Rogers, John Jakicic, Changes in Dietary Intake with Varying Doses of Physical Activity Within a Weight Loss Intervention: The Heart Health Study, Current Developments in Nutrition, Volume 4, Issue Supplement_2, June 2020, Page 1759, https://doi.org/10.1093/cdn/nzaa066_014

2) Virtual abstract presentation from ASN Nutrition Live Online 2020

3) McClave SA, Snider HL. Dissecting the energy needs of the body. Curr Opin Clin Nutr Metab Care. 2001;4(2):143-147. doi:10.1097/00075197-200103000-00011 PubMed

If you want to learn more about the effect of body composition on calorie burn, Tom Chantler has done enough digging on the subject to call out the myth-makers and provide some real numbers in this entertaining article

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