After a controversial DEXA scan claimed he was 14% body fat despite being visibly shredded, Dr. Mike Israetel decided to get to the bottom of body composition testing. He traveled to Cornerstone University's state-of-the-art lab to undergo every major body fat test available.
From the gold-standard underwater weighing to the questionable handheld BIA, Dr. Mike put himself through the ringer. The results were wildly inconsistent, ranging from a stage-ready 3.2% to an "obese" 32.8%, proving just how unreliable some of these methods can be.
TL;DR: Key Takeaways
- The Range was Massive: Dr. Mike's results varied from 3.2% (Underwater Weighing) to 32.8% (BIA Scale). This 30% gap highlights why you shouldn't trust just one test.
- Gold Standards Aren't Perfect: Even "gold standard" tests like the BOD Pod (4.4%) and Underwater Weighing (3.2%) likely underestimated his body fat because of his exceptionally dense bones.
- BIA is "Make Believe": Bioelectrical Impedance (scales and handhelds) gave the most absurd results, labeling a shredded bodybuilder as "obese".
- The Verdict: Dr. Mike estimates his true body fat was likely around 7-8%, meaning the skinfold (9-site) and maybe the 6% DEXA were the closest to reality.
The Test Results: From "Shredded" to "Obese"
Here is the full breakdown of every test Dr. Mike took on the same day:
- Underwater Weighing: 3.2% (The "Gold Standard" likely skewed by high bone density).
- BOD Pod: 4.4% (Also skewed by density).
- Skinfold (3-Site): 4.1%.
- Skinfold (9-Site): 5.9% (Most comprehensive skinfold).
- DEXA (New Scan): 6.0% (Much more realistic than the previous 14%).
- Skinfold (7-Site): 8.3%.
- Waist-to-Hip Ratio: ~12% (Inferred).
- Handheld BIA: 20.4%.
- Standing BIA Scale: 32.8% (Labeled "Obese").
Why Were the Results So Different?
Density Dependent Methods (Underwater Weighing & BOD Pod):
These methods calculate body fat based on your body's density. Muscle and bone are dense; fat is not. However, they rely on "average" bone density assumptions. Dr. Mike's bones are "five standard deviations above average" in density. This extra weight tricks the machine into thinking he has less fat than he actually does, resulting in the impossibly low 3-4% scores.
Bioelectrical Impedance (BIA):
These devices send a weak electrical current through your body. They are calibrated for "average" people (often sedentary undergrads). For a muscular, dehydrated, or older individual, they are essentially random number generators. The standing scale read 32.8%, classifying a visibly vascular bodybuilder as obese.
Which Test Should You Use?
1. Skinfolds (If done by a pro):
If you have access to a professional anthropometrist, this is excellent for tracking changes over time. If you do it yourself or have an unskilled friend do it, it's just guessing.
2. Waist Circumference:
Cheap, easy, and effective for tracking relative progress. While it won't give you a body fat percentage, measuring your waist weekly is a great way to ensure you aren't gaining too much fat on a bulk or to track fat loss on a cut.
3. DEXA & BOD Pod:
Great for occasional check-ins (e.g., end of a diet), but be aware of their error rates (1-3%). Don't obsess over the exact number; look at the trend over months.
Final Verdict
Dr. Mike concludes that his actual body fat was likely in the 7-8% range. This aligns best with the visual reality and the middle-ground tests like the 7-site and 9-site skinfolds. The lesson? Never trust a single number—especially if it comes from a bathroom scale.
Frequently Asked Questions
What is the most accurate body fat test?
Underwater weighing is technically the scientific gold standard, but it is hard to access and can be skewed by bone density. For most people, a professional multi-site skinfold test or a DEXA scan (interpreted with caution) is the best practical option.
Why did the scale say Dr. Mike was obese?
BIA scales are notoriously inaccurate for muscular individuals. They misinterpret muscle mass and hydration levels as body fat because they rely on algorithms based on "average" sedentary populations.
How low was Dr. Mike's body fat really?
Despite tests showing 3-4%, Dr. Mike estimates his true body fat was around 7-8%. He attributes the ultra-low readings to his exceptionally high bone density, which tricks density-based measurements.
