Newsletter #236

Hey y’all, hope everyone is adjusting okay to the shorter days and chillier weather. This week, we wanted to focus on a super fascinating study published this week, which explores dietary factors that lead to overeating.

Of course, we’ve talked a ton about how ultra-processed foods are fattening, but it’s honestly sort of hard to say for sure why. We do know that they are hyperpalatable, energy dense, and tend to be softer in texture compared to whole foods, all of which can contribute to overconsumption.

This paper suggests that another reason why highly processed discretionary foods can contribute to higher energy intake is because they are relatively high in sugar/fat and low in protein, and we have a particular need for protein since amino acids are the building blocks of life. Even worse, the researchers suggest that fat- and sugar-rich savory snack foods may sabotage homeostatic protein-seeking responses due to sharing some of the flavor attributes of protein-rich foods.

To learn more, scroll on down 👀

Researchers at the University of Sydney analyzed data from a cross-sectional survey of nutrition and physical activity in 9341 Australian adults. They plotted energy intake and macronutrient distribution versus timing of consumption, and found that those who ate lower amounts of protein in their first meal of the day increased their energy intake in subsequent meals. In contrast, those who ate a higher proportion of energy from protein at the start of the day had lower energy intake over the course of the day. This pattern lines up with the Protein Leverage Hypothesis, which argues that the body prioritizes protein over other dietary components, and when the diet is “diluted” by fat and carbs, humans are prone to overeating in order to meet that protein target. When the researchers examined what foods were responsible for this protein hunger, they identified ultra-processed foods as a "significant diluent of protein."

Japanese researchers recruited 12 healthy male subjects from three large companies in Tokyo and had them embark on a 2-day trip to forest areas. During the first day, they walked for two hours in the forest, covering about 2.5 kilometers in the journey. On the second day, they walked for two hours in the morning and two hours in the afternoon, again only going about 2.5 kilometers for each course, so this wasn’t an extraordinary amount of physical exercise. Blood work revealed that walking in the forests had significantly increased numbers and activity of these men’s natural killer (NK) cells. NK cells are immune cells that play an important role in defense against bacteria, viruses, and even tumors, and lower NK activity has been shown to be associated with higher risk of going on to develop cancer. Specifically, natural killer cell numbers increased from 440 to 661 (+~50%), and NK cell activity rose from 17.3% to 26.5% (+53.2%). There was also a marked increase in levels of anti-cancer proteins, such as perforin, which is how NK cells attack and destroy cells that are afflicted by viruses and cancer. Interestingly, other studies have shown that walking in urban environments does not elicit the same immune-boosting effect, suggesting that it is something specific about forests (perhaps volatile substances emitted by trees?) that is responsible.

Researchers in New Zealand analyzed data from an experimental trial that included 105 children between 8-12 years of age. The kids went to bed one hour earlier for one week, then had a week of normal sleep, and finally went to bed one hour later for a week. During the study, they were equipped with wrist-worn trackers, and were asked regularly about their eating habits. When the children went to bed later, they lost about 40 minutes of sleep per night, and during that week they ate an average of 74 extra calories per day, but 96 calories more in highly processed snack foods. This lines up with prior research suggesting that sleep loss may make you hungrier and tilt your food intake more toward hyperpalatable, less-healthy stuff.

Researchers at the Medical College of Georgia performed a retrospective analysis of data from more than 41,000 NHANES participants, which had been collected between 1988-2019. They estimated allostatic load — meaning the cumulative effect of stress on the body over time — through levels of various biomarkers, like C-reactive protein, and divided the subjects into groups based on their allostatic load score. Then, they cross-referenced the subjects with the National Death Index to determine mortality and cause of death. They found, after adjusting for a wide range of confounders, that higher allostatic load was associated with increased cancer mortality, especially in younger folks, and there was a marked racial disparity. Specifically, high AL was linked to 95% higher risk in White adults and 2-fold higher risk in Black adults under 40.

Via Collective Insights Podcast.

This week, Dan had the opportunity to chat about deep sleep with Daniel Schmachtenberger. On this show, he goes over the purpose of sleep, the various stages of sleep, and particularly the unique benefits of slow wave sleep. Dan also goes into the role of sleep in immunity, inflammation, muscle-building and repair, appetite regulation, cognitive function, and much more. You’ll definitely come away from this episode with an appreciation for the importance of sleep not just for health but for performance. 💪🏽

Thanks for reading, enjoy the weekend, and we will see y'all next week!

https://mailchi.mp/humanos.me/newsletter-236