The battle against the bulge has attracted a new heavyweight. Takeda Pharmaceutical’s plan to develop obesity drugs with Amylin Pharmaceutical, a US biotechnology group, is the latest twist in Japanese drugmakers’ search for new growth.

The companies are natural partners. Amylin has a record of sorts in obesity, which the World Health Organisation estimates will affect 700m people by 2015. Weight loss is a beneficial side-effect of Byetta, a diabetes drug Amylin sells in partnership with Eli Lilly, a fellow US drugmaker. Takeda, Japan’s biggest drugmaker by turnover, has a big sales force but craves its counterpart’s research pipeline. Takeda also has ample cash to fund costlier late-stage clinical trials.