RESUMO
BACKGROUND: Health campaigns have struggled to gain traction with young adults using social media, even though more than 80% of young adults are using social media at least once per day. Many food industry and lifestyle brands have been successful in achieving high levels of user engagement and promoting their messages; therefore, there may be lessons to be learned by examining the successful strategies commercial brands employ. OBJECTIVE: This study aims to identify and quantify social media strategies used by the food industry and lifestyle brands, and health promotion organizations across the social networking sites Facebook and Instagram. METHODS: The six most engaging posts from the 10 most popular food industry and lifestyle brands and six health promotion organizations were included in this study. A coding framework was developed to categorize social media strategies, and engagement metrics were collected. Exploratory linear regression models were used to examine associations between strategies used and interactions on Facebook and Instagram. RESULTS: Posts from Facebook (143/227, 63.0%) and Instagram (84/227, 37.0%) were included. Photos (64%) and videos (34%) were used to enhance most posts. Different strategies were most effective for Facebook and Instagram. Strategies associated with higher Facebook interactions included links to purchasable items (beta=0.81, 95% CI 0.50 to 1.13, P<.001) featuring body image messages compared with food content (beta=1.96, 95% CI 1.29 to 2.64, P<.001), and where the content induced positive emotions (beta=0.31, 95% CI 0.04 to 0.57, P=.02). Facebook interactions were negatively associated with using pop culture (beta=-0.67, 95% CI -0.99 to -0.34, P<.001), storytelling (beta=-0.86, 95% CI -1.29 to -0.43, P<.001) or visually appealing graphics (beta=-0.53, 95% CI -0.78 to -0.28, P<.001) in their posts compared with other strategies. Posting relatable content was negatively associated with interactions on Facebook (beta=-0.29, 95% CI -0.53 to -0.06, P=.01), but positively associated on Instagram (beta=0.50, 95% CI 0.05 to 0.95, P=.03). Instagram interactions were negatively associated with weight loss (beta=-1.45, 95% CI -2.69 to -0.21, P=.02) and other content (beta=-0.81, 95% CI -1.57 to -.06, P=.04) compared with food content. CONCLUSIONS: Health promotion professionals and organizations can improve engagement using positive messaging and tailoring posts appropriate for different social media channels.