Poor individuals have less healthy diets and seem to benefit less from nutrition information campaigns. One may wonder if they are less aware of their diets’ shortcomings. The aim of this paper is to assess whether the association between perceived diet healthiness and adherence to nutritional guidelines is weaker among poor people. Data were collected from 40,000 participants from the Constances study, a large population-based observational cohort in France. Adherence to French nutritional guidelines was measured by a validated score based on a 22 item food frequency questionnaire and poverty was defined as facing material deprivation. These variables and their interaction were the variables of interest of a linear regression predicting perceived diet healthiness, with controls for confounders and 95% CI. Poor participants had lower nutrition scores and diet healthiness perceptions. Among respondents who had never faced material deprivation, for each increase in the guideline adherence score there was a +0.21 change (95% CI [0.18,0.23]) in perceived diet healthiness for men (women: +0.19 [0.17,0.22]). The coefficients were not smaller among poor respondents. Our results do not support the assumption that people facing poverty might overestimate their diet healthiness. This suggests that information campaigns are not enough: policies or interventions making healthy eating easier and more manageable are necessary.