Newsletter #181: Mindfulness, Stress, and Weight Maintenance 🧘
Hey, humanOS friends! So, this week, we are switching gears a bit and looking into what the evidence says about the impact of mental training that promotes mindfulness (generally through meditation and other behavioral exercises) on stress, and perhaps indirectly on aspects of body weight regulation.
One issue with research in this area from a methodological standpoint is that it often relies upon self-assessment and subjective measures of stress. This is obviously not ideal, because study participants are usually aware that they are engaging in practices that are intended to alleviate stress, which means that they are more likely to report that it works simply due to placebo effects.
Fortunately, some recent studies have started to use objective measures to assess the physiological impact of these practices, such as biomarkers like cortisol.
These practices may be particularly helpful with weight maintenance, as prior research shows that mindfulness is linked to less weight regain in people who have intentionally lost a significant amount of weight. Why might it have this effect? Scroll down to learn more 👇🏼
This Week’s Research Highlights
🤔 Regular contemplative mental training lowers markers of physiological stress.
Researchers in Germany recruited 332 participants and enrolled them in nine months of mental training. This training consisted of three 3-month sessions, each designed to train a specific skill area using Western and Far Eastern mental exercises. After six months of training, the amount of cortisol detected in participants’ hair consistently decreased, by 25% on average, and remained low to the end of the study period. The training effects on cortisol increased with individual practice frequency, but were independent of the content being taught. Lead author Lara Puhlmann said: "We need to work on counteracting the effects of chronic stress in a preventive way. Our study uses physiological measurements to prove that meditation-based training interventions can alleviate general stress levels even in healthy individuals.”
😌 Mindfulness training may decrease abdominal fat through its effects on physiological stress.
Researchers at UCSF randomly assigned 47 overweight (and stressed out) women to one of two groups. 23 of the women were assigned a control group, in which they only attended a session reviewing basics of healthy eating and physical activity, and the other 24 attended nine weekly sessions of mindfulness training and practice, as well as an intensive silent meditation retreat. Despite no prescribed dietary modifications, obese participants in the mindfulness group showed a decrease in visceral adipose tissue, and reductions in abdominal fat were specifically associated with drops in cortisol during the intervention. This suggests that dampening physiological stress, through the mindfulness intervention, may have elicited the observed improvements in this subset of participants.
🧠 Mindfulness-based stress reduction may improve weight maintenance by altering brain connectivity.
Researchers randomly assigned a group of individuals who had recently lost weight to either Mindfulness-Based Stress Reduction (MBSR), or to a healthy living course (control). They performed fMRIs at baseline and at eight weeks to examine functional connectivity between various regions of the brain. The mindfulness group maintained their weight, while the controls showed an increase in BMI, and the mindfulness group also showed changes in the functional connectivity between the amygdala and the ventromedial prefrontal cortex, a circuit that has been implicated in regulation of emotion, reward processing, and self-control. This finding suggests that mindfulness meditation could help with weight loss maintenance through its effects on executive control - basically enabling people to maintain behaviors in alignment with personal goals, despite their short-term impulses.
Random Trivia Question of the Week
What is the greatest weight loss ever by a human (that we know of)?
💡 ANSWER
Podcasts We Loved This Week
- Jeremy Loenneke: The science of blood flow restriction—benefits, uses, and what it teaches us about the relationship between muscle size and strength. Via Peter Attia.
- Ed Green: The ancient neanderthal traces hidden In your genome. Via Science Friday.
The humanOS Bookshelf
Why Zebras Don’t Get Ulcers.
By Robert Sapolsky.
The physiological stress response is highly conserved across different animal species. Fish, birds, reptiles, mammals, etc all secrete certain hormones (adrenaline and glucocorticoids) that raise heart rate and blood pressure, among other effects. This response is adaptive in the face of danger (like, say, if you are a zebra running from a lion on the savannah), and generally short-lived. But humans are somewhat unique because although most of us are never confronted with mortal peril like the zebra, we experience chronic stress. This is, ironically, because we are intelligent enough to induce this state in ourselves, and in each other.
In this book, Dr. Sapolsky explains how prolonged exposure to psychosocial stress affects nearly every organ system - increasing atherosclerosis, suppressing the immune system, shutting down reproduction, disrupting digestion, deranging blood glucose metabolism, etc. Much of Sapolsky’s insights emanate from his decades of research on African baboons in Kenya. These animals are highly social primates that are generally safe and well-fed, but are subject to psychological stress due to interactions with one another. And it turns out that they pay the price for these elevated stress hormones - much like we do.
humanOS Catalog Feature of the Week
Thank you so much, as always, for reading, and see y'all next week!