Why some people are likelier than others to gain weight, develop obesity-related conditions

A new research, part of the largest genome-wide study to date, has strengthened the genetic link to obesity.

By analyzing genetic samples from more than 300,000 individuals to study obesity and body fat distribution, researchers in the international Genetic Investigation of Anthropometric Traits (GIANT) Consortium completed the largest study of genetic variation to date, and found over 140 locations across the genome that play roles in various obesity traits.

By applying novel computational methods to the genetic results, they discovered new biological pathways that are important in controlling body weight and fat distribution.

This work is the first step toward finding individual genes that play key roles in body shape and size. The proteins these genes help produce could become targets for future drug development.

Senior author Cecilia Lindgren said that by finding genetic variants that play an important role in influencing body fat distribution and the ways in which fat distribution differs between men and women, they hope to zoom in on the crucial underlying biological processes.

In the paper focusing on body mass index (BMI), researchers identified 97 genome-wide regions that influence obesity, a finding that tripled the number of previously known regions.

Researcher Elizabeth Speliotes said that the work clearly shows that predisposition to obesity and increased BMI is not due to a single gene or genetic change. The large number of genes makes it less likely that one solution to beat obesity will work for everyone and opens the door to possible ways they could use genetic clues to help defeat obesity.

The researchers note that while some genes involved in obesity could already have been implicated in other aspects of human health, others could be part of novel pathways that are not yet understood. A better understanding of their functions related to body fat and obesity could provide a better picture of the roles these genes play in a variety of diseases.

Finding the genes that increase risk of obesity is only the end of the beginning, says senior author Ruth Loos.

The study is published in 2 companion papers in the journal Nature.