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Nutrition · Chapter 8

Evaluate the Diet Claim

A weight-loss claim is a testable statement about energy, and most of them come with a number hiding inside. Put six familiar claims on the bench, move the inputs, and watch what the claim implies line up against what controlled studies actually measure. Some claims survive partly. Some do not survive at all.

The test bench

How to test any claim

  1. How big, in units? A percentage with no denominator is not a result.
  2. Compared with what? Against nothing, against usual intake, or against a matched control?
  3. In whom, for how long? Eight people for two weeks is a starting point, not a finding.
  4. Measured or observed? Randomized trials test causes; observational studies find patterns.
  5. Does it survive matched energy? Hold total intake constant and see what is left.
This page evaluates claims, not people. Body weight is shaped by genetics, medication, illness, sleep, income and food access — much of it outside anyone’s individual control, and none of it a measure of worth. Nothing here is medical or dietary advice for any individual.
Six popular claimstap one to put it on the bench

Pick a claim

The claim