Why did body fat percentage change after the Styku Studio V5 update?

After updating to Styku Studio V5, body fat percentage (BF%) readings may appear 8–10 percentage points higher — even on scans taken before the update. The root cause: V5 changed the default body composition model from Basic to Advanced. The two models use different reference standards and produce meaningfully different BF% values from the same scan data.

This is expected behavior, not a scanner malfunction.

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The two body composition models

Styku offers two models for calculating body fat percentage. "Phoenix" is the marketing umbrella covering both.

• Basic — A 2-compartment model (fat vs. fat-free mass) calibrated against the Seca BIA device. Produces lower BF% values. This was the default before V5.
• Advanced — A 3-compartment model (fat, lean, bone) validated against DEXA-Hologic using 246 subjects at the Pennington Biomedical Research Center (PBRC) at LSU. Shows a correlation of 0.95+ with DEXA for fat mass. Validated for adults 18+. Produces higher BF% values. This is the V5 default and the only model used in the Styku mobile app.

The difference between the two models is typically 8–10 percentage points for the same person on the same scan. For example, a reading of 21% on Basic may display as 29–31% on Advanced.

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Why historical scans changed

When you switch models, Styku recalculates all historical scans using the currently selected model. The raw 3D scan data is unchanged — only the body composition calculation applied to that data changes. A scan taken months ago may now show a higher BF% because it is being recalculated with the Advanced model.

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Desktop vs. mobile app differences

The Styku mobile app uses the Advanced model exclusively. If your Studio desktop is set to Basic, BF% values will differ between the desktop and mobile app for the same client. BMI is unaffected by model choice — it uses only height and weight.

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BF% classification tables

Advanced model (Mayo Clinic / NIH reference):

Category | Men | Women

Essential | 5–7.9% | 12–15.9%

Athlete | 8–11.9% | 16–22.9%

Fit | 12–20.9% | 23–34.9%

Average | 21–27.9% | 35–39.9%

At Risk | 28%+ | 40%+

Basic model (ACE / WHO reference):

Category | Men | Women

Essential | 2–5% | 10–13%

Athlete | 6–13% | 14–20%

Fit | 14–17% | 21–24%

Average | 18–25% | 25–31%

At Risk | 26%+ | 32%+

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Accidental model switch

If BF% jumped suddenly for all clients, someone may have changed the body composition model without realizing it. Check Settings > Body Composition Model in Styku Studio. Changing it back recalculates all scans immediately.

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Choosing the right model

Pick one model and stick with it. Switching between models makes results not directly comparable.

• Use Advanced for clinical accuracy, health risk assessment, consistency with the mobile app, or when starting fresh with no prior baseline.
• Use Basic for continuity with prior BIA-based results or if your clients are accustomed to BIA readings.

Treat the first scan under a newly selected model as a fresh BF% baseline.

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What to tell your clients

Explain that Styku updated to a body composition model based on a different reference standard. The client's body has not changed — only the measurement approach. Key points:

• The calculation method changed, not their body composition.
• The underlying 3D scan data, circumferences, and shape measurements are unchanged.
• All scans now use the same model, so progress tracking is consistent going forward.
• Focus on trends over time, not single numbers.

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Older printed reports

Previously generated PDFs reflect whichever model was active at print time. If you switch models, re-generate reports for any scans where you need updated BF% values.

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Contacting support

If the steps above do not resolve your issue, contact Styku Support through the Styku Business Portal at styku.com/portal. Include your current Studio version, which model is selected, and example scans showing the discrepancy.

Applies to: All Styku configurations