#242 - AMA #44: Peter's historical changes in body composition with his evolving dietary, fasting, and training protocols
Peter Attia, MD, and Nick Stenson review Peter's 12+ years of DEXA scan results and blood work, analyzing how various nutrition (ketosis, fasting, high protein) and exercise (endurance, strength) protocols impacted his body composition and health metrics.
Deep Dive Analysis
9 Topic Outline
Introduction to AMA #44: Peter's Body Composition Case Study
Evolution of Body Composition Measurement Methods
DEXA Scan: The Gold Standard for Body Composition
Key DEXA Metrics Beyond Body Fat Percentage
Importance of Tracking Health Data Over Time
Peter's 2011 DEXA: Carb-Restricted Diet and Training
Impact of Initial Ketogenic Diet on Body Composition
Body Composition Changes During Prolonged Ketogenic Diet
Transition from Ketogenic Diet to Fasting Experiments
6 Key Concepts
DEXA Scan
DEXA (Dual-energy X-ray absorptiometry) is a type of X-ray that scans the body, accurately dividing tissue into bone, fat, and 'other' (mostly muscle and organs). It is considered the gold standard for body composition measurement.
Visceral Fat
Visceral fat is a compartment of fat stored outside of the safe subcutaneous pockets. When the capacity to store fat in subcutaneous areas is exceeded, fat spills over into visceral areas, which is highly inflammatory and problematic, contributing to disease.
Bone Mineral Density (BMD)
BMD measures the density of bone, assessed via Z-scores (comparing to age/sex-matched individuals) and T-scores (comparing to a 30-year-old). T-scores are used to diagnose osteopenia or osteoporosis.
Appendicular Lean Mass Index (ALMI)
ALMI is a metric of muscle mass calculated by taking the lean mass in your arms and legs (in kilograms) and dividing it by your height in meters squared. It is a purer measurement of muscle mass in the limbs.
Fat-Free Mass Index (FFMI)
FFMI is a metric of muscle mass calculated by dividing the total fat-free mass in your body by your height in meters squared. While it includes torso musculature, it can be somewhat confounded by the mass of organs.
Bathtub Analogy for Fat Storage
This analogy describes fat storage capacity: the bathtub represents one's genetic capacity to store fat in safe subcutaneous space, water coming in is what you eat, and water leaving is energy expenditure. Exceeding bathtub capacity leads to visceral fat spillover, which is problematic.
6 Questions Answered
While body fat percentage is commonly focused on, the most important metrics are visceral fat, bone mineral density (BMD), and muscle mass metrics like appendicular lean mass index (ALMI) and fat-free mass index (FFMI).
Calipers are highly dependent on the skill of the individual performing the test. Hydrostatic testing (underwater weighing) can be inaccurate due to reliance on lung exhalation. DEXA scanning is considered the gold standard for accuracy.
Visceral fat indicates that the body has exceeded its capacity to store fat in safe subcutaneous areas, leading to fat spilling over into organs and other problematic locations. This type of fat is highly inflammatory and contributes to the 'fourth pillar of disease'.
ALMI (Appendicular Lean Mass Index) measures lean mass in arms and legs relative to height, while FFMI (Fat-Free Mass Index) measures total fat-free mass relative to height. Patients are ideally targeted to be north of the 75th percentile for their age and sex for both metrics.
During his ketogenic diet phase (2011-2014), Peter's body weight decreased, and he experienced a loss of both fat mass and lean mass. His body fat percentage initially decreased but then slightly increased, while his FFMI remained high, though it also saw a slight reduction.
From 2011 to 2012, Peter transitioned from primarily swimming and heavy lifting to cycling five days a week, including two very long weekend rides and three 90-minute to two-hour weekday rides, while still lifting weights but less frequently.
4 Actionable Insights
1. Annual DEXA Scan Protocol
Get DEXA scans at least once a year, as it’s considered a very important practice for monitoring body composition and health metrics.
2. Monitor Health Data Trends
Keep a historical record of health metrics, including DEXA data and lab results, to observe trends over time rather than just isolated current numbers.
3. Target High Muscle Mass
Aim to be north of the 75th percentile for Appendicular Lean Mass Index (ALMI) and Fat-Free Mass Index (FFMI) to ensure adequate muscle mass for your age and sex.
4. Recognize Visceral Fat Risks
Understand that visceral fat is highly inflammatory and problematic, contributing to disease, and should be minimized as it indicates exceeding safe fat storage capacity.
4 Key Quotes
Every ounce of non-essential tissue you carry into the ring is problematic.
Peter Attia
Of the four things we're going to talk about today, the least interesting of these is your body fat.
Peter Attia
Trends matter, you're treating what you see but you're mindful of the trends.
Peter Attia
It took three months to just even get over the cliff of maybe it got over the hump I should say of feeling kind of miserable when I exercised and I would say it took me 18 months to get to the point where I couldn't distinguish between being on and off carbohydrates.
Peter Attia