Does Weight Loss Speed Up Or Slow Down The Process Of Ageing?
Aging, and Calorie Restriction: The Low-Down on Staying Young
This week we are diving into world of science and talking telomeres, those tiny protective caps on the ends of our chromosomes. Think of them as the little plastic bits on your shoelaces that stop them from unraveling. Now, what do these microscopic shoelace tips have to do with aging? A whole lot, it turns out!
The Age-Old Question: Why Do Telomeres Matter?
Since the late 20th century, scientists have known that telomeres shorten as we age. But here's the thing – this shortening doesn't happen at a steady pace. In other words, it’s not a linear process because it declines early in life and then as we hit middle age, it begins to slow down. The shortening of telomeres is often used in science to determine the biological age of someone.
Most interesting is how chronic inflammation – sometimes (or often, even) a side effect of obesity – speeds up this telomere trimming process, hinting that it could accelerate aging.
Naturally the assumption is that losing weight can or should slow down this telomere shrinkage. But this is where nutrition science enters the grey area. Because slowing down telomere shrinkage through calorie restrictions just so happens to have a point of diminished returns.
Calorie Restriction: More Than Just "Eat Less"
When we talk about calorie restriction (CR), it's not just about skipping dessert. To nutrition scientists, CR is a lifestyle aimed at extending life and dodging diseases like heart disease and diabetes. It's about eating significantly less than usual with the hope of living longer and healthier.
Enter the CALERIE 2 Study
And sit tight because this is about to get a little geeky…
The CALERIE 2 study (Comprehensive Assessment of Long-term Effects of Reducing Intake of Energy) explored what happens to telomere length when people reduce their calorie intake by 25% for a year and then maintain that lower weight for another year. Interestingly, participants started off with an average BMI of 25.2 – pretty much at the healthy weight borderline.
**This point is really important to note, and we will come back to it later.
The Surprising Results
Participants in the CR group lost over 10% of their initial body weight by cutting their calories by about 12% on average. They maintained this new weight with minimal regain over the following year.
So far so good right?
But here's where it gets twisty: during the first year, those who cut the most calories saw the greatest shortening in their telomeres – quite the opposite of what was expected! In the maintenance phase, however, those who restricted calories had less telomere shortening.
Before we consider these confusing findings, lets first talk about how telomeres are measured.
Measuring Telomeres: Two Different Approaches
Researchers measured telomere length using two methods – one that estimated telomere reduction through DNA damage and another that measured the telomere length directly. Regardless of the method, both CR and control groups had similar telomere reductions after 24 months.
The main difference was that the CR group reached this point faster. Yes, you read that right, the group that were in a calorie restriction saw a greater reduction in their telomere length.
Understanding The Unexpected Results: The Stress of Cutting Calories
Cutting calories is no picnic. It's stressful and challenging, especially for those who are already at a healthy weight.
Remember in the beginning we talked about how these participants were not obese or even overweight, but rather “normal” weight individuals. This stress can shorten telomeres as the body adapts to a lower energy intake.
The Bottom Line
For most of us, the real challenge isn't extreme calorie restriction but avoiding overeating.
We do our best to maintain a balanced diet and let our telomeres take care of themselves. After all, life is unpredictable, and while science offers fascinating insights, sometimes it’s best to enjoy the ride and stay as healthy as we can.
And that means not overeating OR undereating. Not always an easy skill to practice in modern day living.
So, eat well, stay active, and let those telomeres do their thing. Cheers to living a balanced and happy life!
Resources
Ye, Qiaofeng, Abner T. Apsley, Laura Etzel, Waylon J. Hastings, John T. Kozlosky, Cade Walker, Sarah E. Wolf, and Idan Shalev. 2023. “Telomere Length and Chronological Age across the Human Lifespan: A Systematic Review and Meta-Analysis of 414 Study Samples Including 743,019 Individuals.” Ageing Research Reviews 90 (September): 102031.
Welendorf, Caroline, Carolina Ferreira Nicoletti, Marcela Augusta de Souza Pinhel, Natália Yumi Noronha, Bruna Morais Faleiros de Paula, and Carla Barbosa Nonino. 2019. “Obesity, Weight Loss, and Influence on Telomere Length: New Insights for Personalized Nutrition.” Nutrition 66 (October): 115–21.
Hastings, Waylon J., Qiaofeng Ye, Sarah E. Wolf, Calen P. Ryan, Sai Krupa Das, Kim M. Huffman, Michael S. Kobor, et al. 2024. “Effect of Long-Term Caloric Restriction on Telomere Length in Healthy Adults: CALERIETM 2 Trial Analysis.” Aging Cell, March, e14149.
Rochon, James, Connie W. Bales, Eric Ravussin, Leanne M. Redman, John O. Holloszy, Susan B. Racette, Susan B. Roberts, et al. 2011. “Design and Conduct of the CALERIE Study: Comprehensive Assessment of the Long-Term Effects of Reducing Intake of Energy.” The Journals of Gerontology. Series A, Biological Sciences and Medical Sciences 66 (1): 97–108.
Das, Sai Krupa, Susan B. Roberts, Manjushri V. Bhapkar, Dennis T. Villareal, Luigi Fontana, Corby K. Martin, Susan B. Racette, et al. 2017. “Body-Composition Changes in the Comprehensive Assessment of Long-Term Effects of Reducing Intake of Energy (CALERIE)-2 Study: A 2-Y Randomized Controlled Trial of Calorie Restriction in Nonobese Humans.” The American Journal of Clinical Nutrition 105 (4): 913–27.
