Metabolic health: body, brain, behavior
Your brain runs your metabolism. Eating is a decision. The most effective weight-loss drugs ever made work by changing what you want.
Ten weeks tracing what actually happens after you eat, why sleep and timing change it, and what the evidence really shows. Every week is built on a study, and much of the quarter is spent on studies whose results were not what anyone expected.
Three things most people have wrong
Losing body fat is what improves your metabolic health.
Surgeons removed about nine kilograms of fat by liposuction from fifteen women, roughly a fifth of their total body fat. Insulin sensitivity in liver, muscle and fat did not change. Neither did blood pressure, glucose, cholesterol, or a single inflammatory marker. So what is fat for? Klein et al., New England Journal of Medicine, 2004. Week 2.
You should drink eight glasses of water a day.
Heinz Valtin, a Dartmouth kidney physiologist who wrote two textbooks on water balance, searched the literature and asked the specialists. He found no study supporting the rule. The number comes from a 1945 recommendation with a second sentence: most of that water is already in the food you eat. Losing that caveat took fifty years. It can happen in an afternoon now, because a fifteen second video has no room for a sample size or a confidence interval. So what is getting cut from the science on your feed? Valtin, American Journal of Physiology, 2002. Week 1.
Eating within a window beats simply eating less.
A twelve-month trial gave 139 people an early eating window plus calorie restriction, or calorie restriction alone. Both groups lost weight, 8.0 vs. 6.3 kilograms. But everyone in the trial was also counting calories, which is the one thing a window is supposed to save you from. So is a window doing something to your metabolism, or is it just a rule that is easier to follow? And was this ever the study that could tell you? Liu et al., New England Journal of Medicine, 2022. Week 3.
The ten weeks
- What are we even measuring?How metabolic health is defined, and what happens when you go looking for the source of a health claim.
- Glucose and insulinWhat happens after you eat, and what goes wrong when the body runs out of safe places to store fat.
- Not eatingThe fasted state, ketones, and whether intermittent fasting does anything that eating less does not.
- InflammationChronic low-grade inflammation, engineered food, and how carefully to read the work linking inflammation to mood.
- SleepMemory consolidation, and what six short nights do to a healthy twenty-year-old's glucose tolerance.
- Blood pressureThe number students ignore most and the one with the strongest evidence behind it.
- Aerobic trainingZone 2, intervals, and how much of the current enthusiasm the trials actually support.
- Strength and the brainWhy muscle can take up glucose without insulin, and what exercise does and does not do for lifespan.
- Brain healthWhat genuinely raises dementia risk, and the argument that Alzheimer's disease is fundamentally metabolic.
- Everything you've been soldSauna, cold plunge, creatine, and the drugs that changed the field.
Part of a three-course series
- COGS 160 Metabolic Health: Body, Brain, Behavior You are looking at this one.
- COGS 163 Metabolic Brain Disorders
- COGS 163L Metabolic Health Analytics A lab course.
Practical
- Instructor
- Mary ET Boyle, PhD, MPH
- mboyle@ucsd.edu
- Meets
- Tuesdays and Thursdays
- Prerequisites
- None. Every major welcome.