What’s that Junk Food REALLY Costing You?
This is your brain (and liver) on junk food
Welcome!
I’m ever-evolving and trying new things, including turning Nourish. Cultivate. Thrive. Nutrition+ with Dr. Fowler, DCN (my weekly publication) into a more proper newsletter. You’ll still get an article in all of its full-length, deep-dive glory, but I’ll also now include a short welcome message, News & Events (when I have them), What I’m Reading, and a link to the most recent podcast episode.
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In good health,
Dr. F
News & Events
I’m thrilled to be speaking at a new free virtual (on-demand) summit for busy, spiritually-minded moms, the Abundant Mom Summit. The Summit was designed for moms who are ready to align their purpose, intuition, and prosperity.
I’ll be sharing about Hormonal Health – especially as we approach perimenopause. I’d love for you to join me and 15+ other experts for a transformational gathering.
👉 Reserve your spot now! It’s open now through May 15! Plus, when you join the event, you’ll get a bundle of handouts from me to support your blood glucose and cortisol (and a BONUS recipe pack!).
What I’m Reading
This Medscape article about the connection between processed meat (like bacon, prosciutto, bologna, etc.) and colorectal cancer.
Podcast: A Coach, a Nutritionist, and an Expert Walk Into a Podcast
🎧Episode 73: Exercise that's Right for You & Exercise as We Age with Dr Vanessa Cornwell-Chiu
New episodes every Thursday; available wherever you get your podcasts.
Article: What’s that Junk Food Binge REALLY Costing You?
You guys. I love junk food. I know. I’m a doctor of clinical nutrition, I’m probably not “supposed” to say that out loud. But it’s the truth (if you’ve tuned in to the podcast, you’ve probably heard me say this more than once). Do I eat it on a regular basis? No, I do not. And, I’m well aware of the tradeoffs when I do eat it.
I’m not a deprivation-based practitioner. I believe that most foods can be included in a well-balanced manner. That’s not to say I don’t believe in the temporary restriction of some foods (as in the case of a well-executed elimination diet) or the necessity to permanently remove some foods (for instance, gluten or dairy in the presence of intolerance, allergy or other health need).
But, I don’t believe food should be used as reward or punishment, and that’s often where deprivation leads … usually to both.
One of the things that’s never too far from top-of-mind for me is blood sugar and insulin resistance. Why? Because insulin resistance (along with gut health) plays a key contributing role in a whole slew of conditions and diseases, from diabetes and Metabolic Dysfunction-Associated Steatotic Liver Disease (MASLD; what used to be called Nonalcoholic Fatty Liver Disease) to Alzheimer’s disease, obesity, PCOS, and beyond1,2.
And, individuals with hypothyroidism – like me – NEED to be mindful of their insulin sensitivity and blood glucose as they have a higher risk of becoming diabetic3 along with watching their cholesterol levels as they’re at a higher risk of high cholesterol4, especially LDL… why this is, will be covered in a future article.
So, when I saw this recent study about the impacts of a junk food binge on insulin – especially, in the brain and this study on the effects of junk food on memory – they definitely got my attention.
This is Your Brain (and Liver) on Junk Food
Study 1
Let’s start with the study that looked at brain insulin and the effects on the liver.
Who was Studied:
Males only, between the ages of 19-27 years old who were considered generally healthy (“normal” weight (BMI 19-25), no existing medical conditions, no medication or drug use, and non-smokers); they were also omnivores with no food allergies
Small study of 29 participants
Study conducted in Germany; there are no details on race or ethnicity
What was Studied: The effects of a 5-day high-calorie, ultra-processed food fest on 18 participants (11 participants kept their regular diet). Specifically, 5 days of consuming 1,500 extra calories from ultra-processed foods high in fat and sugar aka junk food. Now, if you’re thinking “well, I don’t just sit down and eat a bunch of extra calories for 5 days straight” … think about your last vacation. Maybe that’s not you (bravo!). But, also, maybe it is (no judgies, here).
After 5 days of the added junk food, the 18 junk food participants went back to eating their regular diet.
How were Participants Studied: Food diaries; basic health stats (inclusive of weight and BMI); questionnaires around mood, desire to eat, and cravings; a computer-based reward-learning task; bloodwork for inflammation markers; MRIs, and oral glucose tolerance tests (to test for insulin resistance)
The Results: Are you ready for this?! The insulin in the brains of the participants who had the high-calorie, junk food diet for 5 days was dysregulated for 2 weeks AND there was a significant increase in liver fat content. High levels of fat in the liver is what contributes to MASLD (fatty liver disease).
PLUS:
Insulin activity was significantly higher in the brain compared to the group that consumed their regular diet at the end of week 1; then, after the high calorie group went back to a regular diet, brain insulin was significantly lower (poor function) compared to the regular diet group.
The responsiveness of insulin was correlated with the intake of carbohydrates and variations in saturated fatty acid intake.
Finally, the high-calorie participants showed reduced sensitivity to reward and higher sensitivity to punishment (Yikes!)
Net-Net: What happens today (or over 5 days), can have lasting impacts on the body. Chronic diseases are born out of three things: Repetition, compromised bodily function, and time.
Wait … What was I about to say? (aka: this is your memory on junk food)
Study 2
Okay, so we know that a high fat, high sugar diet (again, in research studies, this tends to be code for “junk food”) can negatively impact cognition (broadly) and cognitive function; this is true for both humans and rodents.
But this study looked at a unique combination of memory and spatial navigation – things like distance, landmarks, and directional information.
Who was Studied:
120 students at the University of Sydney; only 47 successfully completed all parts of the study; 46 completed some but not all parts (due to motion sickness)
Mean age of 20 years old; 24 participants were female
The study was conducted in Australia; there was no data on race or ethnicity
This was a convenience sample (the students were all in a psychology class and participated in exchange for credit), which has its own biases
What was Studied: Memory (using a backward digit span task), spatial cognition (the ability to navigate through a virtual reality maze), and diet.
How were Participants Studied: Participants were given the backward digit span task to test for memory independent of spatial cognition; the virtual reality maze was given through an Oculus VR headset (about 39% of participants experienced “cybersickness” … interestingly, most were female participants); and, diet was measured through a food frequency survey.
The virtual reality maze involved finding a treasure chest; participants had to navigate the maze several times, using “planks” that marked a path while passing landmarks as well as without the planks using landmarks, alone.
The Results: Students with higher intake of fats and sugar performed worse, in general – specifically, they had a decreased demonstrated ability to learn – than those that had lower fat and sugar intake. Students with higher intake of junk food also had a much harder time remembering where the treasure chest was located, let alone how to navigate to it, especially when the plank path was removed and they could only navigate by landmark.
Net-Net: Don’t rely on 20somethings hopped up on junk food to successfully navigate through areas that don’t have clearly marked paths … like when hiking, camping, or finding your car in a parking lot. I’m kidding. Kind of.
While this study was conducted on participants in their 20s (who likely have a bias toward using VR headsets and were primed for cognitive load in an academic setting), think about the implications for aging adult brains that have been exposed to chronic poor eating and lifestyle patterns for much longer. Damn.
Things get a little more dismal when you consider that research also shows the vicious cycles that occur with feeling stressed and eating for comfort and then the foods that are being eaten for comfort causing more stress triggers in the body. While mechanisms for these types of cycles have been investigated with hormone processes and the gut-brain connection, there’s also proposed models that look at the brain-specific reactions that further reinforce these feedback loops.
What Now?
So, is the only solution to not eat junk food? That’s one way to interpret the results, but like I said, I’m not one for deprivation and believe for most people (that don’t have an eating disorder, disordered eating, or other health needs) most foods can be part of a well-balanced diet and lifestyle.
Be aware that everything you choose to eat and drink has tradeoffs – some are positive, some negative and some neutral. All food and beverages impact your body. What you eat and drink provides instructions to your body; it’s data – it tells your body what to do and how to function. It’s why you’ll constantly hear me say FOOD IS FUNCTION.
Go beyond thinking about food as a simple binary of “good”/”bad” or “healthy”/“unhealthy.” Instead, consider what it does for your body, mind and spirit.
Some days that tradeoff will be worth it. On those days, knowing how those foods impact your body can help you offset those tradeoffs and bounce back faster.
References
2 How Can Insulin Resistance Cause Alzheimer’s Disease?
3 Thyroid diseases increased the risk of type 2 diabetes mellitus
4 Treating hypothyroidism decreases cholesterol levels
5 A short-term, high-caloric diet has prolonged effects on brain insulin action in men
6 Consumption of a diet high in fat and sugar is associated with worse spatial navigation ability in a virtual environment
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