Why health systems cannot fix problems caused by food systems: a call to integrate accountability for obesity into food systems policy.

Overweight and obesity now impact one-third of the entire adult population globally, and play a role in the development of 3 of the 4 more common causes of death. Accountability systems for obesity prevention centring on food environment policies and health system strengthening have been vital for raising awareness to the lack of progress in prevention. However, health systems have struggled to prevent and treat obesity - in part because critical food systems reforms largely lay outside the mandate of health sectors and with government agencies for agriculture, industry, infrastructure, trade and investment, and finance. In this commentary we highlight aspects of food systems that are driving poor diets and obesity, and demonstrate a powerful but largely overlooked opportunity for accountability mechanisms for obesity that better address food systems as a main driver. We draw on lessons generated in the Pacific Islands Region where they have demonstrated remarkable commitment to obesity prevention through food system reforms, and the adoption of accountability systems that bring leaders to account on these. We make recommendations for accountability mechanisms that facilitate greater cooperation of food systems sectors on obesity and NCD prevention.