Seven genes have been newly linked to obesity in humans, thanks to two big sequence-sifting studies published in Nature Genetics this week (Times, Financial Times). The Icelandic company deCODE Genetics has the list of seven genetic variants in their paper, and six – including one the deCODE team says was already known – were found by an academic consortium with the happy acronym of GIANT.

The results sound as though ‘mind over matter’ applies even in the biologically big-boned: five of these genes are expressed in the brain.

“Until 2007, no genetic associations had been found for ‘common obesity’, but today almost all those we have uncovered are likely to influence brain function,” says Ines Barroso of GIANT (press release on Science Daily). Her colleague Joel Hirschhorn concludes, “Inherited variation in appetite regulation may have something to do with predisposition to obesity.”

(Besides missing out entirely on the deCODE study, the Independent garbles this bottom line into “Scientists believe that the discovery could lead to new obesity treatments aimed at changing people’s psychology towards food rather than their physical desire to eat.”)

But hold up. Scientists think genetics has a big influence on weight, driving 40-70% of variation in body mass index. This new set of genes, however, makes only a small contribution. The unfortunate 1% of people carrying all seven fattening factors should average 2 kilograms heavier than the general population (Times). The Telegraph here adds “and some much larger”, for no imaginable reason other than to mislead readers who don’t understand the term “average”.

Hirschhorn told the Financial Times that many more genetic variations – perhaps hundreds – probably have small effects on obesity. Since such tiny genetic tweakers are notoriously difficult to track down (Nature subscription required), it seems far too early too draw up totals on the scoreboard of brain-behavior vs. metabolism.