When I first started getting interested in this field and learning more, I know one thing you would hear over and over again is that people who have yo-yo dieted throughout their life have damaged their metabolism and they have a tougher time losing weight in the future.
While there is some truth to this, as you get smaller your resting metabolic rate (RMR) and your non-exercise activity thermogenesis (NEAT) go down with weight loss, however NEAT seems to go down much more than your resting metabolic rate. Which I talk about in this blog here.
Just to clarify, RMR is the energy your body uses for basic bodily functions, so we have no control over this. If you need a refresher on the ins and outs of energy balance, check out this podcast with Danny Lennon of Sigma Nutrition here.
But your RMR doesn’t seem to decrease as much as you would think, so that dispels the dieting kills you metabolism myth.
However, with the combination of decreases in your RMR and NEAT, it can make weight loss tougher and weight regain much easier, especially following a significant weight loss period. This is why with online clients we stress the importance of paying attention to your diet and focusing on stay active (usually through a step tracker) to limit weight regain following a weight/fat loss diet.
So if you have dieted multiple times and regained weight is your metabolism permanently damaged?
In this blog, I am going to go over a recent research review article from James Kreiger that answers this specifically.
What does the research say?
In one of the studies James Kreiger reviews, the authors looked at 52 overweight women with a chronic history of dieting and found that for 48 out of the 52 participants their RMR was what you would predict at that bodyweight, which shows that they did NOT have a “damaged metabolism” from dieting multiple times in the past.
Kreiger shared a quote from the authors in that study:
“Many women in our study were surprised when they were told that their RMR was normal. They strongly believed they had ruined their metabolism through years of dieting.”
Another study Kreiger reviewed looked at , 439 overweight, inactive, postmenopausal women. This study lasted for 12 months and they were grouped into three categories:
- Non-cycler
- Moderate cycler (at least 3 previous weight losses of 4.5 kilograms or more)
- Severe cycler (at least 3 previous weight losses of 9.1 kilograms or more)
What they found is that weight loss and fat loss were the same between the cyclers and non-cyclers. Kreiger did point out that the cyclers started off with worse baseline values (heavier, larger waist circumferences and higher percent body fat) compared to the non-cyclers. However, they still were able to lose just as much body fat as the non-cyclers, showing that even if you have dieted multiple times in the past, you can still lose body fat just and easy as someone who has not dieted before.
This is great news for those of you who have dieted multiple times in the past as you have not done any permanent damage to your metabolism.
What is the downside of yo-yo dieting?
In saying all of this, there can be some downsides to dieting and then regaining over time.
One of the big ones is this:
“Constant weight cycling will result in further adverse changes in overall body composition (successively greater body fat and less relative fat-free mass) with each weight cycle. Thus, you may have further to go with each successive cycle. For example, someone who has cycled 5 times may have more fat to lose than someone who hasn’t cycled before.”
James Kreiger
So the major downside to this approach is that it will negatively affect your body composition, meaning more of your weight will be fat mass compared to fat-free mass (think muscle). And ultimately muscle is what gives your body that “shape” and when people say they want to lose weight, what they really want to lose is body fat.
This is why with online clients we stress the importance of taking time to eat more than normal to build more fat-free mass (muscle), as this will help with your body composition and overall appearance. Read more here. You can also listen to a podcast where me and Jeremiah Bair discuss this in more detail here.
But the good news is that you can still lose body fat just like you always have, you just may have a bit more body fat to lose if you have tried to diet multiple times and then regained it.
As James Kreiger puts it, the keys to a successful fat loss are as follows:
- Energy deficit
- Sufficient protein
- Dietary adherence
- Maintaining/increasing lean mass
- Keeping activity and NEAT high
If you have dieted 15 times and regained it 15 times, there is nothing stopping you from being able to do it again for the 16th time.
If you have struggled with losing weight and then regaining it, you may want to look into your approach to dieting.
Usually, the quicker and more extreme your protocols are, the less sustainable they are, therefore increasing the risk of weight regain.
It may also be a good idea to read over this blog here and here on how to maintain your weight loss.
If you are looking for more structure and guidance around your nutrition fill out the online coaching application here and lets get to work!
References:
McCargar, L. J., Sale, J., & Crawford, S. M. (1996). Chronic dieting does not result in a sustained reduction in resting metabolic rate in overweight women. Journal of the American Dietetic Association, 96(11), 1175–1177. https://doi.org/10.1016/S0002-8223(96)00301-X
Mason, C., Foster-Schubert, K. E., Imayama, I., Xiao, L., Kong, A., Campbell, K. L., Duggan, C. R., Wang, C. Y., Alfano, C. M., Ulrich, C. M., Blackburn, G. L., & McTiernan, A. (2013). History of weight cycling does not impede future weight loss or metabolic improvements in postmenopausal women. Metabolism: clinical and experimental, 62(1), 127–136. https://doi.org/10.1016/j.metabol.2012.06.012
