Fitness influencers: new opinion leaders to challenge public authorities on young people's health?

Influencers have built their visibility on self-presentation, exposing everyday life, and promoting products or brands. Their videos and other content have become essential to the strategy of companies looking to reach a young, mobile, and connected audience. Fitness influencers , in particular, excel in this space: their bodies, their workout routines, and their diets become sales pitches.

However, these same figures now allow themselves to comment on certain public policies, or even to criticize them. When Tibo InShape questions the President of the Republic about a sedentary lifestyle or JuJufitcat talks about eating disorders , the entire mission of the influencer is being redefined . His status is shifting from promoter to prescriber, from prescriber to engaged citizen. He is no longer just there to entertain or recommend, but to alert, raise awareness, and challenge.

Yet this blurring of roles creates tension: some fitness influencers denounce the harmful effects of activities on the health of young people, even though they help to nurture them. For example, they use social media to encourage exercise... while encouraging them to stay connected and sedentary, in front of screens. They advocate a balanced diet while recommending restrictive eating patterns . Here we see the major paradoxes conveyed by this new practice of influence.

How then can we explain why their words carry so much weight? Why do these figures, without scientific training or institutional mandate, manage to capture the attention and often the support of young audiences?

The answer lies partly in their perceived credibility. The Food and Digital (Alimnum) research project , conducted among young people aged 18 to 25, to study the impact of their digital consumption on their health, shows that influencers derive their legitimacy from strong relational proximity . They express themselves with the codes of their generation, in accessible, embodied, emotional language. Their stories are based on experience, the body, and personal transformation.

Where corporate campaigns sometimes fail to mobilize, influencers capture attention by recounting their own journey. Their authority is therefore not "scholarly," but experiential: they don't know "better," but they have "lived."

This is what is particularly valued by the "before/after" rhetoric, omnipresent in fitness content, which showcases an ability to surpass oneself, to change, to improve one's well-being.

This autobiographical narrative is all the more effective because it relies on an illusion of proximity. Subscribers feel as if they know their influencer, follow their life, and share their intimacy.

On the surface, this proximity appears to be a result of strong ties between the influencer and their audience. In reality, it is more a result of weak ties . Followers do not know the influencer personally, do not interact with them in depth, but interact regularly: they like , comment, share. However, it is precisely these weak ties that allow the exponential spread of ideas and behaviors.

This co-construction of influencer legitimacy by the community is central. Influencers are not imposed from above: they are validated, supported, and reinforced by their community, which symbolically elects them as a figure of authority and trust. They therefore achieve the status of opinion leader through a cumulative viral interaction.

This dynamic is reminiscent of the two-step flow model of communication , widely used by marketing professionals, in which the media first influences a select group of opinion leaders, who then relay the messages to the general public. This model, which originated in the 1950s, is now finding new resonance in contemporary digital practices, by playing on a virality shaped by algorithms.

Encouraged by their community, influencers are now speaking out to public authorities about the distress and difficulties facing young people. In doing so, they are helping to popularize and encourage the general public to understand major health issues, even if this sometimes involves oversimplifications or approximations.

By translating complex messages (health, nutrition, prevention) into short, personalized, engaging content, and adapting them to platform formats (reels, vlogs, stories) and the sensitivity of their audience, they play the role of true relays.

Should we be pleased with this mobilization of fitness influencers around collective causes? Their ability to reach audiences far removed from traditional media, to provoke emotion, and to generate support, is real. It helps rekindle civic awareness in spaces where official discourse often struggles to penetrate.

But this power of amplification also comes with risks related to the dissemination of unclear, biased, or erroneous messages. Their words, based more on experience than on scientific proof, can then reinforce certain problematic social norms such as the cult of performance, the obsession with the body, or the stigmatization of "non-conforming" bodies.

In any case, Tibo InShape's intervention in front of the President of the Republic in May 2025 marks a symbolic step in the evolution of public speaking: one where personalities from digital culture arrogate to themselves a right of expression on issues of general interest.

This dynamic is redrawing the legitimation circuits: authority no longer comes solely from institutions, but emerges from the network, the audience, and virality. This requires us to rethink the relationships between the public and digital spheres, between experts, citizens, and new mediators. It also requires accepting that these opinion leaders are neither neutral nor disinterested, and that their engagement may fluctuate depending on opportunities for visibility or monetization.

Furthermore, the ethical legitimacy of using media figures in public health campaigns is being questioned. What responsibilities should these influencers assume, and how can we ensure the reliability of the messages they convey? These issues call for in-depth consideration by healthcare professionals, researchers, and educators involved in regulating health information.

The Food and Digital – ALIMNUM project is supported by the French National Research Agency (ANR), which funds project-based research in France. The ANR's mission is to support and promote the development of fundamental and finalized research in all disciplines, and to strengthen the dialogue between science and society. For more information, visit the ANR website.