Hi everyone,
This was a fascinating week. A brain imaging study found that a specific type of daydreaming, one where your mind drifts to your heartbeat and breathing, is linked to fewer symptoms of depression and ADHD. A new study suggests that over a quarter of older adults on thyroid medication may not need it anymore. And one of the most surprising findings I came across: whether meat protects or harms your brain may depend entirely on a single gene that one in four people carry. I also covered GLP-1 drugs on the podcast this week, and the tradeoffs are more complex than most people realize.
This Week’s Podcast Spotlight
Episode 39: The Science Behind GLP-1 Drugs and Their Hidden Tradeoffs
GLP-1 drugs like Ozempic, Wegovy, Mounjaro, and Zepbound are everywhere right now, but most of us do not really understand how they work or what the real downsides are. I did a deep dive this week, tracing the science from a forgotten observation in 1906 Liverpool all the way to the billion-dollar drugs on the market today. What fascinated me most was the history: a mysterious factor found in intestinal extracts, a breakthrough from Gila monster venom, and a pharmaceutical scientist named Lotte Bjerre Knudsen who spent her career engineering the molecule that eventually became semaglutide.
The clinical results are impressive. Semaglutide can reduce body weight by 12 to 16%, and tirzepatide achieves up to 22%. But here is the part that does not get enough attention: 25 to 40% of the weight lost may be muscle, not fat. For older adults, that muscle loss can be dangerous. I also talk about why the Mediterranean diet combined with resistance training can produce comparable results with zero medication side effects, and I lay out a practical framework for who should consider these drugs and who should be cautious.
Three things worth knowing from this episode:
- GLP-1 drugs work by activating receptors in your pancreas, brain, stomach, and heart. The appetite suppression comes from brain effects, not just slowing your stomach.
- If you lose 40 pounds on semaglutide, 10 to 16 of those pounds could be muscle. Protein intake of 1.6 to 2 grams per kilogram of lean body weight and resistance training are non-negotiable while on these drugs.
- The strongest candidates for GLP-1 drugs are people with type 2 diabetes plus obesity, especially with existing cardiovascular or kidney disease. Older adults over 65 with limited muscle mass should proceed with great caution.
This Week in Health Science
Here is what stood out from the research this week. These studies fascinated me, and I think you will find them practically useful.
A Specific Type of Daydreaming May Protect Against Depression and ADHD
This one completely changed how I think about mind-wandering. We usually assume that a wandering mind is a distracted mind, but a brain imaging study of 536 adults found that people whose thoughts drift toward body sensations, things like their heartbeat, breathing, or gut feelings, report significantly fewer symptoms of both depression and ADHD. The researchers found a unique brain connectivity pattern during this type of daydreaming, suggesting it is a genuinely different brain state, not just regular daydreaming with a different topic. If you tend to reach for your phone during quiet moments, try noticing your breathing instead. It might be more beneficial than you think.
Key finding: People who naturally focus on body sensations during daydreaming had significantly fewer depression and ADHD symptoms, with a unique thalamus connectivity pattern confirming this is a distinct brain state.
Swapping One Hour of TV for Reading Could Cut Dementia Risk by 7%
Not all sitting is created equal. A 19-year study of more than 20,000 Swedish adults found that passive sitting activities like watching TV raised dementia risk, while mentally active ones like reading, puzzles, and crafts lowered it. Replacing just one hour of daily passive screen time with a mentally engaging activity was linked to a 7% lower chance of developing dementia. When researchers combined mental engagement with physical activity, the benefit jumped to 11%. This is the kind of change that is small enough to actually stick: swap an hour of scrolling for a book, a puzzle, or a craft project.
Key finding: Replacing one hour of daily TV with reading or puzzles was linked to 7% lower dementia risk over 19 years, and pairing it with exercise boosted the benefit to 11%.
Many Older Adults May Be Able to Stop Their Thyroid Medication
Levothyroxine is one of the most commonly prescribed medications in the world, and many patients start it and never revisit whether they still need it. A new study of 370 adults aged 60 and older found that about 26% were able to stop taking levothyroxine and maintain normal thyroid function one year later. Among those on low doses of 50 micrograms per day or less, nearly 64% succeeded. That is almost two out of three patients on low doses who no longer needed their prescription. This does not mean anyone should stop on their own, but it is a conversation worth having with your doctor, especially if you have been on a low dose for years.
Key finding: 26% of adults over 60 successfully stopped levothyroxine, with the success rate jumping to 64% for those on low doses of 50 micrograms per day or less.
Binge Drinking Once a Month Triples Your Risk of Serious Liver Damage
This one is worth paying attention to if you drink at all. A study of over 8,000 U.S. adults with fatty liver disease found that those who binge drink even once a month are three times more likely to develop advanced liver scarring compared to those who drink the same total amount spread over time. Think of your liver like a recycling plant: a steady, manageable load gets processed fine, but dumping a whole week’s worth in one night overwhelms the system. About 16% of adults with fatty liver disease reported this pattern of drinking, and many of them probably do not consider it a problem because it is only occasional.
Key finding: People with fatty liver disease who binge drink even once monthly have three times the risk of advanced liver fibrosis, regardless of their total weekly alcohol consumption.
Eating More Meat May Protect Your Brain, but Only If You Carry This Gene
This study challenges the blanket advice to eat less meat. A 15-year Swedish study of 2,157 older adults found that people with the APOE4 gene variant, the strongest known genetic risk factor for Alzheimer’s, showed significantly slower cognitive decline when they ate more meat. At low meat intake levels, APOE4 carriers had more than twice the dementia risk compared to non-carriers. But as meat consumption increased, that extra risk essentially vanished. About one in four people worldwide carry this gene variant. The catch: regardless of genotype, eating less processed meat was linked to lower dementia risk. So if you are curious about your genetic status, talk to your doctor about testing, and choose fresh cuts over bacon and hot dogs.
Key finding: Higher meat intake neutralized the extra dementia risk in APOE4 gene carriers, but processed meat was linked to higher risk for everyone regardless of genetics.
My book, 2mm, is almost here. It is the story of seven years inside the operating room, where every decision is measured in millimeters and every millimeter matters. If you want to be the first to know when it is available, leave your email at 2mmbook.com.
Eating the Same Meals Every Day Helps You Lose More Weight
I find this one really practical. A study of 112 overweight or obese adults found that people who ate the same meals repeatedly lost an average of 5.9% of their body weight over 12 weeks, compared to 4.3% for those with varied diets. Calorie consistency mattered too: for every 100-calorie increase in daily fluctuation, weight loss dropped by about 0.6%. The likely reason is decision fatigue. When you eat the same meals, you spend less mental energy planning and tracking, and you are less likely to make impulsive choices. Think of it like a uniform for your diet. Pick 3 to 5 balanced meals you enjoy and rotate through them.
Key finding: Repetitive eaters lost 5.9% of their body weight over 12 weeks, compared to 4.3% for varied eaters, with calorie consistency playing a key role in the difference.
Stay curious. Stay skeptical. And stay healthy.
Dr. Kumar