The article investigates the Russian dialect, plain speech lexemes, phraseologisms and aphorisms which define negatively-estimated food - low-fat soup and weak tea. The analysis provides a background of data from other Slavic languages, primarily Polish, Ukrainian and Belarusian. The study reveals the aspects of motivation for naming “junk” food. The names of low-fat soup and weak tea are designed to reflect the dish's colour, cooking technology and ingredients, denoting those who cooked the dish or ate it, or times of starvation when this product used to be a primary foodstuff, among other aspects. The authors propose a semantically-motivated interpretation of ‘vague' names: demyanova ukha, loshchenka, kulikovy ryzhiki etc.