Myth: Slow Weight Loss is Way to Go


Gradual weight loss is not better than losing weight quickly.

Central Obesity

Central Obesity

Imagine you are 10-20 pounds lighter.  You no longer had to spend 30 minutes struggling to get into those new jeans that you thought would fit.  Your growing belly or waistline will cease to bulge over your belt.  Your shirt would stay tucked, and you would not bear unmentionable areas when you bend to get something off the bottom shelf at the grocery store.  Most importantly, you would not fear nauseating others when you remove your shirt or wear a bathing suit at the pool.  Have you tried slow diets and failed?  This article may highlight research that may help you make a change.  

You may call me a pessimist, but I alway doubt research.  When you read any study, I suggest you do the same and channel your inner pessimist and don’t blindly accept what the researchers claim.  Instead, think of the flaws in the research and how the research may or may not apply to you.  

Any one is have been around for more than a day has read an article on either fast or slow weight loss.  I have always been taught that slow or gradual weight loss is better for weight loss management or maintenance.  Guidelines have long recommended gradual weight loss for the treatment of obesity, and this indicates a widely held opinion that weight lost rapidly is more quickly regained.  It just makes sense that slow weight loss will give you the tools to build a routine to keep the weight loss.  You learn to add exercise into your day and how to cook and eat healthy of the longer duration of you weight loss program.  The problem is that this does not pan out in the research.  I want to stress that I am not saying that crash diets are healthy.  You should not go the extreme and go below 1200 calories per day without a medical provider’assistance.   Several studies now show that losing weight fast, but in a SAFE manner (LET ME STRESS SAFE), is not problematic and neither fast nor slow prevents weight gain.

A study completed in 2010 entitled “The effect of rate of weight loss on long-term weight management: a randomised controlled trial” and published in Lancet in 2014 looks at just this question[1].  The study was a two phase, randomised, non-masked, dietary intervention trial completed in a Melbourne metropolitan hospital in Australia.  Phase 1 was the weight loss arm, and phase 2 was the weight maintenance arm.  The researchers enrolled 204 participants (51 men and 153 women) that aged 18–70 years and had a BMI between 30 and 45 kg/m2.  During phase 1, they randomly assigned participants, while accounting for sex, age, and BMI, to either a 12-week rapid weight loss or a 36-week gradual program.  Both dietary interventions aimed at a 15% weight loss in their respective time frames so in other words, the 12-week group represents rapid weight loss.  Those that completed phase one with 12.5% or more weight loss graduated from phase 1 and were enrolled in phase 2.  In phase 2, subjects were placed on a weight maintenance diet for 144 weeks.   

broken bathroom scales

broken bathroom scales

So what did they find?  After phase 1, 50% participants in the gradual weight loss group 81% in the rapid weight loss group achieved the goal of 12·5% or more weight loss in the allocated time.  This difference was a statisticaly significant difference in success between the two groups.   At the end of phase 2, neither gradual weight loss and rapid weight loss participants showed a significant difference in weight maintenance.  Seventy percent of both groups suffered weight regain.  In fact, they regain almost all the weight they lost.  This data confirms what we already know, and that is that weight loss is difficult and often results in weight regain no matter which diet you choose.  This research proves that the hardest part of losing weight is actually just keeping it off.

So this is only one study?  An additional study entitled “The Association Between Rate of Initial Weight Loss and Long-Term Success in Obesity Treatment: Does Slow and Steady Win the Race?” was published in the International Journal of Behavioral Medicine in 2013 found very similar results[2].  They concluded that there were both short- and long-term advantages to fast initial weight loss.  Fast weight loss obtained greater weight reduction and long-term maintenance and this group was equally susceptible to regaining the weight that was lost during the first phase. 

I sense a “but.”   These are good research studies that refute many of the prior “theories” that were not encased in facts and backed by research.  The problem with them is that they do not address safety or the metabolic impact of rapid weight loss.  A study published in 2016 in the journal Obesity[3] indicated that the participant in the show had a metabolic adaptation that resulted in a slowing of the metabolism to 500 calories lower than would be expected through their body mass change.  This difference is a concern because it would reduce their ability to keep the weight off or lose weight in the future.  I would like to see this study repeated to see if there is an adaptation is a slower loss.  

The bottom line: Gradual weight loss is not better than losing weight quickly, and rate of weight loss does not affect the proportion of weight regained within 144 weeks.  These findings are not consistent with present dietary guidelines which recommend gradual over rapid weight loss if regain is the concern.  Quick weight loss resulted in the same net loss as gradual weight loss but was significantly more successful at producing more successful dieters.  That being said, it would be expected if more are successful at losing weight than more would be successful at keeping it off (in pure raw numbers), even if the percentages are the same.  The fundamental difference between the two groups is that the rapid weight loss wing has a lower drop out rate.  This difference is likely due to the subject being able to see day to day progress more readily.  The results also confirm two things we already know: it doesn’t matter how fast you lose weight on a diet, you are probably going to gain most of it back anyway, and the hardest part of losing weight is actually just keeping it off.  This study does not address safety or metabolic changes that occur with weight loss, so I still recommend a weight loss of 1 to 2 pounds a week weight loss goal after the first two weeks.

[1]Nackers, Ross, and Perri, “The Association Between Rate of Initial Weight Loss and Long-Term Success in Obesity Treatment: Does Slow and Steady Win the Race?”
[2]Purcell et al., “The Effect of Rate of Weight Loss on Long-Term Weight Management: A Randomised Controlled Trial.”
[3]Fothergill et al., “Persistent Metabolic Adaptation 6 Years after ‘The Biggest Loser’ Competition.”
Fothergill, Erin, Juen Guo, Lilian Howard, Jennifer C. Kerns, Nicolas D. Knuth, Robert Brychta, Kong Y. Chen, et al. “Persistent Metabolic Adaptation 6 Years after ‘The Biggest Loser’ Competition.” Obesity 24, no. 8 (May 2, 2016): 1612–19. doi: 10.1002/oby.21538
Nackers, Lisa M., Kathryn M. Ross, and Michael G. Perri. “The Association Between Rate of Initial Weight Loss and Long-Term Success in Obesity Treatment: Does Slow and Steady Win the Race?” International Journal of Behavioral Medicine 17, no. 3 (May 5, 2010): 161–67. doi: 10.1007/s12529-010-9092-y
Purcell, Katrina, Priya Sumithran, Luke A Prendergast, Celestine J Bouniu, Elizabeth Delbridge, and Joseph Proietto. “The Effect of Rate of Weight Loss on Long-Term Weight Management: A Randomised Controlled Trial.” The Lancet Diabetes & Endocrinology 2, no. 12 (December 2014): 954–62. doi: 10.1016/s2213-8587(14)70200-1 [Source]
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About the Author

I am a family physician who has served in the US Army. In 2016, I found myself overweight, out of shape, and unhealthy, so I made a change to improve my health. This blog is the chronology of my path to better health and what I have learned along the way.

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