Why Your Gym’s Illustrated Facebook Ads Feel Right But Don’t Sell

Four marketing researchers built two Facebook ads for an invented grocery delivery brand they called Orange Delivery. This experiment was designed to test whether a photograph vs illustration in ads would create different responses. Both ads offered a free month of delivery, used the same layout, and carried the same call-to-action. The only thing that changed between them was the image: a photograph of a woman holding a bag of groceries in one ad, and a cartoon of the same woman holding the same bag in the other.

Seventy-six people on Prolific saw each version, and each was asked whether they wanted to click through and claim the free month.

Seventy-one per cent of the people who saw the photograph clicked through. For the illustrated version it was forty-six.

Canva is the default design tool for small gyms, and its fitness ad library skews heavily toward illustrated templates. An illustrated ad doesn’t need a release form from any member. It can be put together on a Sunday night with a glass of red in hand. And it tends to pick up positive comments on Facebook because it’s easy to look at.

What People Say They Like Versus What They Actually Do

Elmashhara, Salgado Pinto, Nabih and Rocha ran five studies across 1,210 participants. Three of them used real customers of Mercadão, a Portuguese grocery service owned by Glovo, who saw a Facebook post for the brand and filled out a survey: 206 customers in Study 1a, 319 in a Study 1b replication with a different image pair, and 346 in a Study 2 that fed the structural equation model. Study 3 is the Orange Delivery experiment at the top of this post. A pre-study of 187 people validated the image manipulation before any of the main work.

Across the survey-based studies, photographs scored higher on interest, an engagement construct close to alertness and attentiveness. Illustrations scored higher on enjoyment, a pleasure construct close to delight and happiness. Participants said the illustrated ads were nicer to look at.

When the researchers moved from what participants said to what they actually bought, enjoyment dropped out. In Study 2, on 346 Mercadão customers, the structural equation model gave enjoyment a slightly negative coefficient on purchase intention, and the effect wasn’t statistically significant. Good feelings didn’t sell anything.

Study 3 dropped the survey. A hundred and fifty-two Prolific users who regularly use online delivery services saw one of the two ads. Each ad used a standard Facebook sponsored-post layout, with the brand name at the top, the image below, and a call-to-action button under the image. Participants were given a binary choice: click through for the free month, or don’t. The click-through rates were 71.1 per cent for the photograph and 46.1 per cent for the illustration.

What the Brain Does With a Face

In the human brain, the region that handles face recognition treats a real face as a source of social information about the person: who they are, what mood they’re in, whether they can be trusted. A photograph of a woman holding groceries gives the brain enough of that signal to form a quick judgement about her. The cartoon version gives it much less.

The researchers measured credibility on two dimensions drawn from Ohanian’s (1990) endorser-credibility scale: attractiveness and trustworthiness. Photographs scored higher than illustrations on both, but only trustworthiness predicted purchase. In Study 2, on 346 Mercadão customers, trustworthiness was the strongest predictor of whether someone said they would buy. Attractiveness didn’t reach significance, and enjoyment didn’t either.

What This Means for a Gym Facebook Ad

Illustrated content produces pleasant feelings, and pleasant feelings don’t predict who buys. A gym running a mostly illustrated ad cycle gets engagement the owner enjoys reading, and a cost per lead that runs higher than it should. The paper’s authors note that illustrated imagery fits storytelling posts and community content, where the goal is atmosphere rather than conversion. Trouble shows up on the ads with a booking link.

A stock photograph of a woman in sports luxe holding a perfect plank is technically a photograph, but the woman is real and nobody recognises her. Put the ad in front of someone on Facebook who lives ten minutes from the gym, and a slightly awkward picture of an actual member at the end of a 5:45am session will convert better.

The Nuance Most Gyms Get Wrong

Two of the twelve hypothesised mediation paths didn’t replicate cleanly across Studies 1a and 1b. Samples skewed female and Western, and most of the earlier findings rely on Likert-scale self-report rather than observed behaviour. The direction of the main finding held across every study, including the behavioural one: photographs beat illustrations on clicks.

The ad a gym owner likes looking at and the ad a cold prospect clicks on are often different ads. This is attribute substitution: the brain answers the easy question (do I enjoy looking at this) and lets the answer stand in for the harder one (do I trust these people enough to hand over my card details).

Research Summary

Study	Sample	Finding
Elmashhara et al. (2026), Studies 1a and 1b	525 real Mercadão customers across two Facebook ad tests	Photographs drove more interest and more trust. Illustrations drove more enjoyment.
Elmashhara et al. (2026), Study 2	346 real Mercadão customers, SEM analysis	Interest and trustworthiness predicted purchase intention. Enjoyment and attractiveness did not.
Elmashhara et al. (2026), Study 3	152 Prolific participants, binary click decision	Photograph ad: 71.1% clicked through. Illustration: 46.1%. Same offer, same layout.

The Question

When did you last run a gym Facebook ad with a real photograph of a real member, taken in your own gym, without retouching?

People Also Ask

Do illustrated Facebook ads work for gyms?

Illustrated ads tend to generate more enjoyment-based engagement than photograph-based ads, but fewer clicks on offers. Elmashhara et al. (2026) found photographs produced a 71.1% click-through rate on a grocery delivery ad compared with 46.1% for the illustrated version of the same ad. The photograph is the stronger choice for a conversion ad, and illustrated content fits storytelling, entertainment and community posts.

Why do real photos outperform illustrations in gym social media marketing?

The brain processes faces for social information before it processes anything else in an image, and photographs carry that information in detail. Illustrations strip most of it out, which is part of why illustrated content feels pleasant to consume but doesn’t carry trust.

Should gyms ever use illustrations in their advertising?

Yes, when the job is atmosphere or entertainment rather than conversion. Illustrated content works for storytelling posts, community celebrations, and challenge-style content. It’s a poor fit for trial offers or membership ads, where the prospect has to trust the gym enough to hand over a phone number or a card.

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The illustration is the ad the gym owner’s eye likes. Conversions come from somewhere else.

References

1. Elmashhara, M.G., Salgado Pinto, S., Nabih, Y., & Rocha, L.N. (2026). Why a human image is better than a human illustration in social media advertising. Journal of Retailing and Consumer Services, 92, 104830. https://doi.org/10.1016/j.jretconser.2026.104830
2. Izard, C.E. (1977). Human Emotions. Plenum Press.
3. Ohanian, R. (1990). Construction and validation of a scale to measure celebrity endorsers’ perceived expertise, trustworthiness, and attractiveness. Journal of Advertising, 19(3), 39–52.

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If your gym’s marketing could use more research like this, fitnessisbs.com has more of it.