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Glossary

Leptin

Defined in topic 13

A hormone made by fat. Its main job appears to be reporting starvation rather than preventing obesity: it falls when food runs short, and blocking that fall blunts starvation's effects.

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Where this comes from

In the reference topic that owns this term

Reference topic 13, The Thrifty Body, states the mismatch as a card: what the system evolved to expect, what it gets instead, and what happens in the gap.

Mismatch card

What it expects

Food that takes work to get, lean seasons, fiber-rich plants and hours of physical work.

What it gets

Cheap, energy-dense, ultra-processed food all day, little physical work and short sleep.

What happens in the gap

Fat accumulates, a body built to defend its stores resists losing it, and fat that overflows into liver, muscle and pancreas is thought to drive insulin resistance and type 2 diabetes.

The full card, and the topic behind it

What that chapter recommends

3 of the 7 graded recommendations in Reference topic 13, strongest evidence first. How the grades work.

  1. Move for insulin sensitivity, not to burn off food

    StrongEvidence grade: Strong. Multiple randomized controlled trials, or consistent large cohort studies with a well-understood mechanism.

    Aim for 150-300 minutes a week of moderate activity plus resistance training on two or three non-consecutive days. A session can improve insulin sensitivity for 2 to 72 hours, so avoid more than two days off in a row.

    Read it in full

  2. Act early

    StrongEvidence grade: Strong. Multiple randomized controlled trials, or consistent large cohort studies with a well-understood mechanism.

    With prediabetes, a program aiming at 7% weight loss and 150 minutes of weekly activity cut diabetes incidence by 58% over about three years.

    Read it in full

  3. Treat GLP-1 drugs as a legitimate medical option

    StrongEvidence grade: Strong. Multiple randomized controlled trials, or consistent large cohort studies with a well-understood mechanism.

    chosen with a clinician and planned as long-term treatment, since weight usually returns after stopping. The trials enrolled adults with a BMI of 30 or more (27 with a weight-related condition).

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Related terms

The argument behind this term, its studies and its notes are in Reference topic 13 of the reference library. The book gives the practical version. Get the book.