Food Myths, Rated

Seed oils, sweeteners, detoxes, alkaline diets and the rest — each rated against the evidence, with the honest alternative.

What this is

Food myths persist because they offer a single villain and a simple fix. The evidence rarely cooperates: most of these claims are either contradicted outright or rest on mechanisms that don't survive contact with human outcome data.

Each row below is rated on its own evidence. Where a myth has a legitimate kernel, we say so — that's usually why it spread.

What the evidence says

  • Seed oils cause inflammation and heart disease

    Not supported

    The opposite is better supported. A pooled analysis of 30 cohort studies found higher circulating linoleic acid — the main omega-6 in seed oils — associated with lower cardiovascular disease and lower cardiovascular mortality, and a separate meta-analysis found similar for mortality. The inflammation story comes from mechanistic reasoning that human data haven't borne out.

  • Detoxes and cleanses remove toxins

    Not supported

    Your liver and kidneys do this continuously. No juice, tea or supplement protocol has been shown to enhance it, and the named toxins are rarely specified.

  • Alkaline diets change your blood pH

    Not supported

    Blood pH is tightly regulated within a narrow range; food doesn't shift it. Alkaline diets tend to be high in vegetables, which is why some people feel better — for entirely different reasons.

  • Artificial sweeteners are dangerous at normal intakes

    Unproven

    Approved sweeteners have extensive safety review at typical intakes. Effects on weight and the microbiome are debated and effect sizes small — worth watching, not worth fearing.

  • Microwaves destroy nutrients

    Not supported

    Microwaving is often gentler than boiling, because shorter cooking times and less water mean less nutrient loss.

  • Eating after 8pm makes you gain weight

    Not supported

    Total intake is what matters. Late eating associates with weight gain mostly because late eating tends to be extra eating.

  • "Clean eating" as a health framework

    Unproven

    No agreed definition, no outcome evidence, and a well-documented association with restriction and food anxiety. The underlying advice — more whole foods — is fine without the moral framing.

What this means in practice

  • Ask what outcome was measured. Mechanisms are hypotheses; mortality, disease incidence and body composition are results.
  • Ask who benefits from the claim. Villain foods sell alternatives.
  • Prefer changes that add something — more fibre, more protein, more plants — over changes that remove a food group.
  • Use our supplement and food reference pages to check specifics rather than relying on a viral graphic.

When to see a doctor

  • A rule that requires eliminating an entire food group without a diagnosis.
  • Escalating anxiety about ingredients, or avoiding eating with other people.
  • Advice that only makes sense alongside buying the advisor's product.

The honest summary

Nearly every popular food villain fails on human outcome data, and seed oils fail most clearly — the pooled cohort evidence points the other way. The cost of these myths is restriction, expense and worry, not the food.

Work it out

See also

Frequently asked questions

Are seed oils bad for you?
The human evidence doesn't support it. A pooled analysis of 30 cohorts found higher circulating linoleic acid associated with lower cardiovascular disease and mortality. The inflammation argument is mechanistic reasoning that the outcome data contradict.
Do I need to detox?
No. Your liver and kidneys do it continuously, and no commercial cleanse has been shown to improve on that. The tiredness people are trying to fix usually has a findable cause worth investigating.
Are sweeteners worse than sugar?
Approved sweeteners have extensive safety review at normal intakes. Debate continues about weight and microbiome effects, with small effect sizes. Replacing sugary drinks with diet ones is not the risky end of anyone's diet.

Sources

Written and reviewed by Mathew Beale, MSc Biotechnology, University of Reading.

Last reviewed: