Lipids are an essential part of the human diet affecting biological processes and reducing disease development.Plant-based oils, specifically sterols, are essential compounds for cellular composition and proliferation. As vegetarians refrain from consuming animal products, although many versions of this lifestyle exist, plant oils are their only source of fat intake. Extracted plant oils are an essential source of fats and fatty acids; hence this study aims to address vegetarians knowledge and pessimistic perceptions of fats and plant oils to understand the vegetarian consumer choice through the Theory of Planned Behaviour. Despite extensive research on the vegetarian lifestyle, a pessimistic approach to understanding consumer choice in plant-based oils has been less than satisfactory. A qualitative research design was selected to conduct one-to-one in-depth interviews with seventeen vegetarian participants that met the eligibility criteria. Recruitment was based on a purposive sampling drawn from social media groups to provide an insight into the pessimistic views of vegetarians on plant-based oils. A thematic analysis was conducted using the computer-assisted software package NVivo 12 Plus. Pessimistic views and lack of knowledge on the functionality of fats and fatty acids may lead to nutrient deficiencies. The study has identified three major themes related to vegetarians pessimistic views towards plant oils: 1) pessimistic misconceptions of fats and plant-based oils, 2) pessimistic views on plant-based oil harvesting and manufacturing, and 3) plant-based oil challenges and pessimistic health claims. These conflicts are affecting the nutritional status of vegetarians by either avoiding or lessening extracted plant oils in their diet due to a lack of misinformation and uninformative nutritional labelling. The present study highlights the vegetarians' pessimistic perceptions of extracted plant oils. It argues that vegetarians' are more prone to nutritional deficiencies due to a lack of knowledge on the functionality of fats and fatty acids and highlights the need for informative food labelling to enable consumers to make comprehensive food choices.