Multimodal AI for Body Fat Estimation: Computer Vision and Anthropometry with DEXA Benchmarks
Bibliographic record
Abstract
Tracking body fat percentage is essential for effective weight loss and health management, yet gold-standard methods such as DEXA scans [1], [2] are too expensive and rarely accessible for most people. This study aims to evaluate the feasibility of artificial intelligence (AI) models as low-cost alternatives using frontal body images and basic anthropometric data. The dataset consists of 535 samples: 253 cases with recorded anthropometric measurements (weight, height, neck, ankle, and wrist) and 282 images obtained via web scraping from Reddit posts self-reported body fat percentage values, some of which were stated to be derived from official DEXA scans. As no publicly available datasets exist for computer vision based body fat estimation, this dataset was compiled specifically for this study. Two approaches were developed: (1) ResNet-based image models, (2) regression models using measurements only. A multimodal fusion approach was proposed but could not be implemented due to the lack of paired datasets, and is identified as future work. The image-based model achieved a Root Mean Square Error (RMSE) of 4.44% and a Coefficient of Determination$(R^{2})$of 0.807. These results show that AI-assisted models and tools can give low-cost and accessible body fat estimates. This supports a future of consumer based weight loss and fitness apps.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.002 | 0.004 |
| Meta-epidemiology (narrow) | 0.002 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.002 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.003 | 0.002 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".