TempoLife › Features › Weekly research digest
Weekly research digest
One study a week, read in full and summarised in plain language, graded on a published evidence ladder. The archive is empty: the standard is published here first, and nothing is invented to fill it.
There are no digest entries yet. Nothing on this page is a study summary, because no study has been summarised yet. What follows is the standard the digest will be written to — published before the first entry, so it can be held against it.
The archive
Empty, honestly. A digest that opened with twenty back-dated entries would be a digest nobody wrote. This one opens with the rules instead.
The feed exists and is valid from today, so you can subscribe before the first entry lands rather than remembering to come back: RSS feed. It currently carries zero items.
What one entry contains
Every entry fills the same seven sections in the same order. A fixed template is not a stylistic choice: it is what stops a summary from quietly becoming an argument, because the sections that would undermine a good story have to be filled in too.
| # | Section | What goes in it |
|---|---|---|
| 1 | The claim in one sentence | What the study is being reported to show, in the words a reader would meet in a headline. |
| 2 | What the study actually did | Design, how many people, for how long, and what was compared with what. |
| 3 | What it found | The result with its absolute numbers and its uncertainty, not the relative headline. |
| 4 | Evidence grade | One rung of the ladder below, with the reason for that rung. |
| 5 | Limitations | The specific reasons this result might not hold — named, not hedged with "more research is needed". |
| 6 | What it changes in practice | Usually nothing. When the honest answer is "nothing yet", the entry says nothing yet. |
| 7 | The study | A direct link and a DOI, so you can read the paper rather than our summary of it. |
The evidence ladder
Every entry is graded on the ladder below, strongest at the top. The grade describes the design of the study, not how much we liked the result, and it is the first thing printed on the page — before the finding — so the finding is read in the right light.
A rung is not a verdict. A well-run cohort of 90,000 people followed for twenty years frequently tells you more that is useful than a four-week trial in twelve students. The ladder ranks what a design can establish, and the limitations section carries the rest.
| Rung | Design | What it can show | What it cannot show |
|---|---|---|---|
| 1 | Systematic review and meta-analysis | Whether a finding survives when every study that asked the question is pooled with a pre-declared search and inclusion rule. | It cannot rescue a body of weak studies. A meta-analysis of ten small, poorly controlled trials is still weak evidence, pooled. |
| 2 | Randomised controlled trial | Cause. Randomisation is the only design that makes the compared groups alike in everything except the thing being tested. | It cannot tell you much about people unlike the ones enrolled, and short trials cannot show long-term outcomes. |
| 3 | Prospective cohort study | Association over time, in ordinary life, at a scale no trial can afford — and the correct time order, because exposure is recorded before the outcome. | It cannot rule out confounding. People who eat more fibre also move more, smoke less and earn more; statistics can adjust for that only imperfectly. |
| 4 | Case-control study | A fast, cheap signal for rare outcomes: find people who already have the outcome and look backwards for what differed. | It cannot escape recall bias. People who are already ill remember their diet differently from people who are not. |
| 5 | Cross-sectional survey | What a population looks like at one moment: how common something is, and what travels with it. | It cannot establish time order at all. A survey cannot tell whether the diet came before the weight or after it. |
| 6 | Animal, cell or in-vitro study | A mechanism worth testing in people, and a dose range worth starting from. | It cannot support a human recommendation. A compound that kills cancer cells in a dish also does that at concentrations no person could ever reach. |
How to spot which rung you are on
- Systematic review and meta-analysis. Reports a search strategy, a PRISMA flow diagram and a heterogeneity statistic.
- Randomised controlled trial. Participants were allocated by chance, ideally with blinding and a registered primary outcome.
- Prospective cohort study. A defined group is enrolled, measured, and followed for years.
- Case-control study. Cases are matched to controls and past exposure is reconstructed.
- Cross-sectional survey. Everything was measured once, on one day, in one questionnaire.
- Animal, cell or in-vitro study. The subjects are mice, rats, or cells in a plate.
How to read a study yourself
The point of the digest is not that you should trust our summary. It is that a study is readable if you know which six things to check. These are those six, and they are the checks each entry has to pass before it is written.
Effect size, not just "significant"
Statistical significance answers one narrow question: how surprised should we be by this result if the treatment did nothing at all? It says nothing about size. With enough participants, a difference of 200 grams over a year becomes "highly significant" and remains, in every practical sense, nothing. Read the number of kilograms, millimetres of mercury or minutes of sleep, then decide whether you would change anything for it.
Absolute risk, not relative risk
A headline that says a food "raises your risk by 30%" is quoting a relative change. If the outcome happened to 2 people in 1000 and now happens to about 2.6 in 1000, that is a 30% relative rise and a 0.06 percentage-point absolute rise. Both numbers are true; only the second one tells you what it means for you. Every entry in this digest will print the absolute numbers where the paper reports them, and will say so when the paper does not.
Sample size and who was in it
Twelve young male athletes for four weeks is a pilot study, whatever the conclusion says. Ask two questions of every trial: how many people, and how like you were they? Results from trained twenty-year-olds routinely fail to reproduce in sedentary fifty-year-olds, and results in men have repeatedly failed to reproduce in women. Small studies also swing wildly, which is why the first study of anything is usually the most exciting and the least reliable.
Preregistration and the primary outcome
A well-run trial declares, before it starts, what it will measure and how. That declaration is public — on ClinicalTrials.gov, the ISRCTN registry or the OSF. It matters because a study that measures thirty outcomes will find something impressive by chance alone. If the paper's exciting result is not the outcome the registration named, treat it as a hypothesis for the next study, not a finding.
Who paid, and who benefits
Funding is not disqualifying — much good nutrition science is industry-funded because nobody else pays for it — but it is information. Read the conflict-of-interest statement, note who sponsored the trial, and weigh a result that happens to favour the sponsor's product slightly more carefully than one that does not. The same applies to authors who sell a book about the thing they just tested.
Was the comparison fair?
A diet study is only as good as what it compares against. "Better than the standard American diet" is a low bar. "Better than an equal-calorie, equal-protein alternative" is a real one. In exercise research, watch for a control group that did nothing at all, which measures the effect of attention and routine as much as the intervention.
What this digest will not do
- Report a study from a press release. If the paper is paywalled and we cannot read the methods, it is not summarised.
- Print a relative risk without the absolute risk beside it.
- Turn a single trial into a recommendation. One study changes what is plausible, not what you should do.
- Give medical advice, or suggest changing a medicine, a treatment or a diagnosis. That conversation belongs with a clinician who knows your history.
- Quietly correct an entry. Corrections are dated, kept on the page and stated in the entry that carried the error.
- Publish an entry generated without a human reading the paper. Entries are inserted as drafts by an editor and published by hand.
Source: TempoLife editorial policy · checked 2026-09-02
Frequently asked questions
Why is the archive empty?
Because no entry has been written yet, and filling an archive with plausible-looking summaries of studies nobody read would be a fabrication. The evidence ladder, the entry template and the six checks are real and usable today; the entries will appear one per week once the first one is genuinely written.
Where does the RSS feed live?
At /research/feed. It is a valid RSS 2.0 document today and currently carries zero items, so you can subscribe now and receive the first entry when it is published.
Does a study on this list mean TempoLife endorses it?
No. An entry means a study was read, graded and summarised, limitations included. A large share of entries will end with "this changes nothing in practice", which is the honest outcome for most single studies.
How is the grade decided?
By the design of the study alone, using the ladder on this page. A meta-analysis of weak trials is still labelled a meta-analysis, and the limitations section says the underlying trials were weak.
Nutrition myths, checked · Glossary · All features
Test a finding on your own numbers
A study reports an average. TempoLife records what actually happens to you — meals, steps, sleep and weight in one place — so a change you read about here can be checked against your own trend.