Scientists Discover ‘Thinness Gene’ Explaining Why Some People Stay Slim Without Trying

by : Julia Banim on : 24 May 2020 11:05
Scientists Discover 'Thinness Gene' Explaining Why Some People Stay Slim Without TryingPixabay/Shutterstock

I for one am currently struggling to pull on my pre-lockdown jeans without taking a big breath in, and I know I’m certainly not alone.

However, there are those who are apparently able to stay slim without so much as breaking a sweat; chomping down on sugary treats without having to loosen their belts.


Now a team of scientists believe they have discovered a ‘thinness gene’, which would explain why some people don’t struggle as much as others to keep their weight down.


The gene in question is known as anaplastic lymphoma kinase (ALK), and is located in the hypothalamus, the region of the brain responsible for controlling appetite and how an individual controls fat.

For the study, published in scientific journal Cell, researchers searched a database of 47,102 people in Estonia between the ages of 20 to 44. This included clinical information as well as biological samples.


The team identified thin, healthy individuals in the lowest 6th percentile of weight. Those identified as being within the 30th to 50th percentile were the control group, while those in the 95th percentile were marked out as the obese group.

The scientists then proceeded to pinpoint variants of genes that appeared to emerge more often in the thin group. They then looked for the genes in flies in an attempt to identify those with a long evolutionary history, picking out ALK as a probable ‘thinness gene’.

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To find out whether ALK does play a part in controlling weight, researchers experimented with the gene in flies and discovered that levels of triglycerides – the form most fats take in both food and in human bodies – was reduced.


After repeating the same technique in mice, the animals were found to have lost weight and did not become obese. This was despite them following the same diet and having the same amount of movement as other mice.

According to the researchers, the mice experiments suggest ALK affects a brain circuit which tells fat tissue to burn more calories.


The study authors wrote that healthily thin people, ‘often have the desire to gain weight and have normal food intake and frequently snack, indicating they have a metabolic rather than hedonic low body weight’.


Co-author of the study, Dr. Josef Penninger, believes the research could lead to treatments for obesity, but added, ‘Obviously, a pill cannot replace a healthy lifestyle,’ though the impact of this research could be ‘huge in the long term’, Newsweek reports.

Going forward, more extensive studies will be required to examine the extent to which genes can impact weight gain.

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Julia Banim

Jules studied English Literature with Creative Writing at Lancaster University before earning her masters in International Relations at Leiden University in The Netherlands (Hoi!). She then trained as a journalist through News Associates in Manchester. Jules has previously worked as a mental health blogger, copywriter and freelancer for various publications.

Topics: Health, Diet, obesity, Science, weight


Cell and 1 other
  1. Cell

    Identification of ALK in Thinness

  2. Newsweek

    'Thinness Gene' Could Explain Some People Stay Slim Without Trying