· 11 sources · confounding
The Problem with Changing Five Things at Once
Why changing several eating and lifestyle habits at once makes results hard to explain, and how factorial trials and matched designs untangle them.
Investigation No. 3 ·
The weight came off. Who did it?
When a plan changes food, timing, sleep and activity together, the result can be real while the explanation is a guess. We follow the evidence behind competing explanations of metabolism, and say plainly what it can and cannot show.
Read the caseThe usual suspects
Someone changes five things and loses weight. Each of these could have contributed, alone or together, and several have direct evidence behind them.
Food composition
Removing packaged snacks changed what they ate.
Total intake
Through appetite, convenience or fewer eating occasions.
Activity
Walking added movement.
Sleep
Not a neutral background change. In one trial, extending sleep cut intake by about 270 kcal a day.
Being watched
Being observed does change behaviour, though how much and when is unclear.
Regression to the mean
People often start a plan at a high point; some change might have happened anyway.
Early water shifts
Glycogen is stored with roughly three to four parts water.
“When the same evidence confirms every theory, it cannot tell them apart.”
Investigations
Each opens with what the evidence supports, grades its claims with defined labels, and lists every source. Sources checked Oct 16, 2026.
· 13 sources · animal studies
What Can a Mouse Study Tell Us About Human Weight Regulation?
What can mouse studies tell us about human weight? How housing temperature, diets, strain and sex shape results, with leptin and meal timing as test cases.
· 9 sources · metabolic theories
What Would Count as Evidence for a Metabolic Theory?
What counts as evidence for a metabolic theory? Discriminating predictions, evidence types and confidence labels, using the carbohydrate–insulin debate.
The mouse said, the human said
Mice are good at showing that a mechanism can work, and poor guides to how large an effect will be in people.
| Test case | In mice | In people |
|---|---|---|
| Leptin | Reversed obesity in leptin-deficient mice. | Did the same in leptin-deficient children, but gave modest, variable weight loss in adults with common obesity. |
| Meal timing | An eight-hour feeding window protected mice on a high-fat diet from obesity at equal calories. | Human trials so far have not shown a comparable weight advantage. |
| Room temperature | Mice lacking the heat-producing protein UCP1 became obese when housed warm, not at standard lab temperatures. | No human test. It is a reminder that lab conditions can flip a result, which is why the checklist asks how animals were housed. |
Before you act on a clue
No mouse study on its own is a reason to take a supplement, buy a product or change a medicine. If you take medicine for diabetes or blood pressure, are pregnant, have a chronic illness or a history of disordered eating, talk to your clinician before changing how or when you eat.