Through social media like Instagram, users are constantly exposed to “perfect” lives and bodies. Research in this field has predominantly focused on the mere time youth spend on Instagram and the effects on their body image, oftentimes uncovering negative effects. Little research has been done on the root of the influence: the consumed content itself. Hence, this study aims to qualitatively uncover the types of content that trigger youths’ body image. Using a diary study, 28 youth (Mage = 21.86; 79% female) reported 140 influential body image Instagram posts over five days, uncovering trigger points and providing their motivations, emotions, and impacts on body image. Based on these posts, four content categories were distinguished: Thin Ideal, Body Positivity, Fitness, and Lifestyle. These different content types triggered different emotions regarding body image, and clear gender distinctions in content could be noticed. The study increased youths’ awareness of Instagram's influence on their mood and body perception. The findings imply that the discussion about the effects of social media on body image should be nuanced, taking into account different types of content and users. Using this information, future interventions could focus on conscious use of social media rather than merely limiting its use.