Enter a supermarket and the dilemma is all too common: Will what I buy be healthy? Fattening? A substitute? That's when many wish they had a specialist at their side.

Shop with Your Doc, a program organized by a network of hospitals in the US state of California, aims to help with that, stationing doctors and nutritionists in supermarkets to aid customers in navigating food choices in a country where a third of the population is obese.

Chih-I Lee, shopping in a supermarket in the city of Irvine, admits that she has a weakness for fizzy soft drinks.