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SOURCES & REFERENCES

The science behind your numbers

Physique AI's estimates, reference ranges, and recommendations are based on the peer-reviewed research and public health guidelines below. Tap any source to read it.

AI photo-based body composition

Physique AI estimates body composition from your photos using an AI model. Published studies of AI 2D-photo methods report average errors of roughly 2–4 percentage points against DEXA, with wider variation for any individual person. These studies validate the general approach, not Physique AI specifically. Treat any single reading as an estimate with a margin of error — the trend across scans is the more reliable signal.

Body fat percentage

The share of your body weight that is fat tissue, estimated from your photos. Healthy-range categories follow American Council on Exercise (ACE) norms; photo-based estimation carries a meaningful margin of error for any individual, which is why we emphasize change over time rather than any single reading.

Lean body mass

Your body weight minus estimated fat mass — muscle, bone, water, and organs. Research links maintaining lean mass to better long-term health outcomes.

Skeletal muscle mass

The trainable portion of lean mass. Higher muscle mass and strength are associated with lower all-cause mortality in population studies.

Body fat mass

Total fat tissue in pounds — body-fat percentage × body weight. Interpretation ranges follow ACE norms and WHO guidance on healthy body composition.

Subcutaneous fat

Fat stored just under the skin — the majority of total body fat for most people. Estimated as a share of total fat mass; reference methods are described in the body-composition literature.

Visceral fat

Deep abdominal fat surrounding the organs. Elevated visceral fat is associated with higher metabolic health risk; precise measurement requires clinical imaging such as DEXA.

Total body water

A directional estimate of hydration mass, typically ~60% of lean mass. Clinical measurement methods are described in the body-composition literature.

BMR (basal metabolic rate)

Calories burned at complete rest, calculated with the peer-reviewed Mifflin-St Jeor equation from your sex, age, height, and weight.

TDEE (total daily energy expenditure)

Your BMR (Mifflin-St Jeor equation) multiplied by a standard activity factor to estimate total daily calorie burn.

BMI (body mass index)

Weight relative to height (703 × lb / in²). Categories — underweight, healthy, overweight, obesity — follow CDC and WHO classifications. BMI does not distinguish fat from muscle.

BWI score

Physique AI's own Body Wellness Index — an illustrative 0–10 composite of how your estimated body fat compares with ACE healthy-range norms, adjusted for scan confidence. It is not a clinical or diagnostic measure.

Fitness age

An illustrative estimate comparing your body composition with typical values for your age group, based on ACE body-composition norms. It is not a clinical or diagnostic measure.

Weight & progress trends

Trend guidance follows CDC recommendations: gradual change of about 1–2 pounds per week is more likely to be maintained.

AI Coach recommendations

Training guidance follows WHO and U.S. HHS physical activity guidelines (150–300 min/week of moderate activity plus strength training ≥2 days/week). Protein targets follow the ISSN position stand (~1.4–2.0 g/kg/day for building or maintaining muscle) and the U.S. RDA baseline (0.8 g/kg/day).

DEXA calibration

DEXA (dual-energy X-ray absorptiometry) is a clinical reference method for body composition. Uploading a DEXA result lets Physique AI anchor the specific body-composition values your report actually contains — typically body fat percentage, fat mass and lean mass — to those measured figures. Metrics your report does not cover (for example total body water, fitness age or our own BWI score) remain photo-derived estimates with their usual margins of error.

Important

Physique AI provides body composition estimates for fitness and informational purposes only. It is not a medical device and does not provide medical advice, diagnosis, or treatment. Consult a healthcare professional before making significant changes to your diet or exercise routine.