Although it is not clear exactly how hunger [?] an influence on [?], past research [?] social, cultural and psychological [?] are involved.

In some societies where [?] is a limited resource, [?] the South Pacific, [?] body weights are revered. In others [?] food is abundant, such as the West, lower female body weights [?].

Evolutionary psychologists [?] this is a survival preference. What you [?] in a mate is the [?] chance of healthy [?] and in an environment where food is [?], a [?] woman [?] a [?] bet for this.

What [?] regarded as a normal and acceptable body size is [?] influenced by [?], including advertising, and can change. For example, [?] from rural to urban societies show an increasing idealisation of [?] figures.

Dr Viren Swami from University College London and Dr Martin Tovée from Newcastle University believe there are biological factors at work too.