Dietary Patterns Compared · Evidence, People, and Local Plates

Story

Connected to · 3

regulates · 2

Vitamin B12
Plant-based eating is a spectrum, and the further toward vegan it goes, the less B12 has a reliable food source: plants contain no reliable B12, and vegans who do not supplement will sooner or later run short. Eating healthily does not make it enough on its own; it takes supplements or fortified foods, with periodic checks of methylmalonic acid (MMA) or homocysteine.
IBS
Low FODMAP is not a long-term way of eating but a three-stage diagnostic protocol for managing the symptoms of irritable bowel syndrome (IBS): strict restriction for 2-6 weeks, then reintroducing foods one group at a time in small amounts, and finally avoiding only the ones you personally do not tolerate. In the Gibson 2017 review, six randomised trials comparing it with placebo-style control diets were uniformly positive; the ACG 2021 guideline gives it a conditional recommendation with very low quality evidence.

contrast · 1

Cognitive Aging & Reserve
The MIND diet was designed specifically to protect cognition. In a cohort study, people who stuck to it closely had cognitive decline slower by the equivalent of 7.5 years of age (Morris 2015), but that is an observed association; in the only randomised controlled trial (Barnes 2023, 604 people, 3 years), cognition improved in both groups with no difference between them, and the control group also ate a healthy diet with mild calorie restriction. So saying MIND has been proven to prevent dementia goes too far.

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The pattern landscape

EVIDENCEGUIDE 2 · REVIEW 3 · RCT 3 · COHORT 1

READ THE ORIGINAL

Start with one premise: no single dietary pattern is best for everyone, because they were never built to solve the same problem. Mediterranean and DASH were designed for long-term risk in the general population; the ketogenic diet was first designed for epilepsy that drugs cannot control; and low is not a long-term diet at all but a diagnostic procedure for finding trigger foods. Using a therapeutic diet as everyday eating, or using an everyday way of eating to treat a disease, is the most common mistake in this area.

The weight of the evidence also varies a lot. Here, four levels describe certainty of evidence — how sure we are, not how big the effect is:
High: several randomized trials that agree, or systematic reviews of themModerate: one large randomized trial, or consistent large cohort studies plus a mechanism that makes senseLow: mostly observational studies, or small, short trials that look only at stand-in markersVery low: case reports, animal experiments, mechanistic reasoning, or expert opinion
Low certainty does not mean useless, but it does mean more caution.

Educational content, not medical advice — consult a clinician.

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Dietary Patterns Compared · Evidence, People, and Local Plates

Story

Connected to · 3

regulates · 2

Vitamin B12
Plant-based eating is a spectrum, and the further toward vegan it goes, the less B12 has a reliable food source: plants contain no reliable B12, and vegans who do not supplement will sooner or later run short. Eating healthily does not make it enough on its own; it takes supplements or fortified foods, with periodic checks of methylmalonic acid (MMA) or homocysteine.
IBS
Low FODMAP is not a long-term way of eating but a three-stage diagnostic protocol for managing the symptoms of irritable bowel syndrome (IBS): strict restriction for 2-6 weeks, then reintroducing foods one group at a time in small amounts, and finally avoiding only the ones you personally do not tolerate. In the Gibson 2017 review, six randomised trials comparing it with placebo-style control diets were uniformly positive; the ACG 2021 guideline gives it a conditional recommendation with very low quality evidence.

contrast · 1

Cognitive Aging & Reserve
The MIND diet was designed specifically to protect cognition. In a cohort study, people who stuck to it closely had cognitive decline slower by the equivalent of 7.5 years of age (Morris 2015), but that is an observed association; in the only randomised controlled trial (Barnes 2023, 604 people, 3 years), cognition improved in both groups with no difference between them, and the control group also ate a healthy diet with mild calorie restriction. So saying MIND has been proven to prevent dementia goes too far.

Read full story

Stop 1/9

The pattern landscape

EVIDENCEGUIDE 2 · REVIEW 3 · RCT 3 · COHORT 1

READ THE ORIGINAL

Start with one premise: no single dietary pattern is best for everyone, because they were never built to solve the same problem. Mediterranean and DASH were designed for long-term risk in the general population; the ketogenic diet was first designed for epilepsy that drugs cannot control; and low is not a long-term diet at all but a diagnostic procedure for finding trigger foods. Using a therapeutic diet as everyday eating, or using an everyday way of eating to treat a disease, is the most common mistake in this area.

The weight of the evidence also varies a lot. Here, four levels describe certainty of evidence — how sure we are, not how big the effect is:
High: several randomized trials that agree, or systematic reviews of themModerate: one large randomized trial, or consistent large cohort studies plus a mechanism that makes senseLow: mostly observational studies, or small, short trials that look only at stand-in markersVery low: case reports, animal experiments, mechanistic reasoning, or expert opinion
Low certainty does not mean useless, but it does mean more caution.

Educational content, not medical advice — consult a clinician.