Why Are My Clients’ Scan Results “Wrong”?

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One of the most common concerns raised by trainers and scan users is that results appear inconsistent or inaccurate from scan to scan. In most cases, results are not wrong—they are reflecting changes in total body water (TBW).

Total body water is the single most important metric to understand when interpreting an Evolt scan. Because bioelectrical impedance analysis (BIA) relies on the body’s water content to estimate body composition, even small changes in hydration can significantly influence results.

What Is Total Body Water (TBW)?

Total Body Water refers to the total amount of fluid contained in the human body.

The average adult is composed of approximately 55–65% water
TBW includes:
- Intracellular water (inside muscle cells)
- Extracellular water (outside cells, including blood plasma)

On the results sheet, TBW should remain relatively stable when scans are taken under consistent conditions.

Expected Range

Normal fluctuation: ±1% or ~1 kg
Larger fluctuations typically indicate changes in pre‑scan conditions, not true body composition change

Why TBW Matters in BIA Technology

BIA technology works by sending a low‑level electrical current through the body.

Water and lean tissue conduct electricity well
Fat tissue resists electrical current

Because of this, BIA does not measure fat directly—it estimates fat and lean mass based on how easily the current travels through the body.

Fluid Shifts and Their Impact on Results

When Total Body Water Drops

If body water decreases:

Electrical resistance increases
The algorithm interprets this resistance as:
- Lower skeletal muscle mass (SMM)
- Higher body fat mass
- Higher body fat percentage (BF%)

This can occur even if:

The client has not lost muscle
The client has not gained fat

Common causes include:

Dehydration
Low‑carbohydrate or ketogenic diets
Alcohol consumption
Poor sleep
Illness
Sweating, heat exposure, or sauna use

When Total Body Water Increases

If body water increases:

Electrical resistance decreases
Results may show:
- Higher skeletal muscle mass
- Lower body fat mass
- Lower body fat percentage

Again, this does not necessarily represent:

Muscle gain
Fat loss

It is often driven by:

Improved hydration
Increased carbohydrate intake (glycogen + water storage)
Creatine or electrolyte use
Post‑training muscle inflammation
Hormonal‑related fluid retention

What to Watch for on Every Scan

TBW Is Your First Checkpoint

When reviewing a client’s results, the first metric to assess is Total Body Water.

General guideline:

Acceptable variation: ~1 kg
A shift of 2, 3, 4, 5 kg or more strongly suggests a change in one or more pre‑scan conditions

Large TBW shifts almost always explain sudden movements in:

Skeletal Muscle Mass
Body Fat Mass
Body Fat Percentage

How TBW Changes Appear on the Result Sheet

TBW Change	Likely Result Changes
TBW ↓	↓ SMM, ↑ Body Fat Mass, ↑ BF%
TBW ↑	↑ SMM, ↓ Body Fat Mass, ↓ BF%

These changes are directionally linked and should always be interpreted together—not in isolation.

Key Coaching Message for Clients

If a client questions their results:

Reassure them that the scan is accurately reflecting their current physiological state
Explain that hydration consistency is critical for meaningful comparisons
Redirect focus to long‑term trends, not single‑scan fluctuations

Key Takeaway for Trainers and Staff

Scan results are rarely “wrong.”
They are most often misinterpreted due to changes in total body water.

By paying close attention to TBW at every scan and educating clients on factors that influence hydration, trainers can:

Build trust in the technology
Deliver clearer consultations
Prevent unnecessary frustration or confusion

Consistency creates clarity.

Unrealistic Negative Result

Unrealistic Positive Result

Total Body Water Increase

Total Body Water Decrease

ECF Higher than 35%

ICF Higher than 65%

The Effects Of Carbohydrates