Accepted answer
The short version: enzymes in this class usually fall as weight falls, and a rise is a reason to look for a cause rather than to assume a drug effect.
Alanine aminotransferase is relatively liver-specific; aspartate aminotransferase is also present in muscle, heart and red cells. A raised AST with a normal ALT after heavy resistance training is usually muscle, and creatine kinase settles the question.
Relative to absolute, worked
| Quantity | Value | Derivation |
|---|
| Control-arm event rate | 8.0 % | From the trial table, not the abstract |
| Hazard ratio | 0.80 | Reported |
| Treated event rate | 6.4 % | 8.0 × 0.80 |
| Absolute risk reduction | 1.6 pp | 8.0 − 6.4 |
| Number needed to treat | 63 | 1 ÷ 0.016 |
| Relative risk reduction | 20 % | 1 − 0.80 |
The last two rows describe the same finding. Only one of them is used in headlines.
Very rapid weight loss can transiently worsen liver biochemistry, which is one of several arguments against pursuing the steepest possible trajectory.
Population data show a substantial fraction of adults with mild transaminase elevation attributable to hepatic steatosis, which sets the base rate against which any new finding should be read.
Isolated mild elevation is common and usually improves with weight loss.
edited 30 Sept 2025 by cold_lane — added the method parameters