Social Media Advertising Performance Analysis: Facebook vs Instagram

Instagram Beats Facebook Where It Counts — But Not How Advertisers Expected

An analysis of gym brand ad campaigns reveals a counterintuitive truth: spending more, reaching more, and getting more clicks may all be the wrong goals.

When Planet Fitness, Crunch Fitness, Orangetheory, and Anytime Fitness set out to win customers through social media advertising, they turned to the two dominant platforms in the game: Facebook and Instagram. What the data from those campaigns reveals, however, challenges some of the most deeply held assumptions in digital marketing.

A performance analysis of ad campaigns across both platforms — examining impressions, spend, click-through rate (CTR), and conversion rate (CVR) — found that bigger budgets, broader reach, and higher engagement do not reliably produce better results. In fact, in several key areas, they work against advertisers.

The Reach Trap

Conventional wisdom holds that more impressions mean more conversions. Get your ad in front of more people, and more people will act on it. On Facebook, that logic holds — barely. The data shows a slight positive relationship between impressions and conversions, suggesting that expanding reach can still nudge results upward.

On Instagram, the opposite is true. More impressions are associated with fewer conversions, pointing to a well-documented but often ignored phenomenon: ad fatigue. When users see the same ad too many times, they stop responding — or worse, develop a negative association with the brand. Instagram’s audience, it seems, is quicker to tune out.

The broader takeaway is sobering for brands that measure success by how many eyeballs they reach: impressions are a weak predictor of performance on either platform.

Spending more buys less than you think

The relationship between ad spend and conversions tells a similarly deflating story. Across both Facebook and Instagram, increasing the budget showed little to no consistent improvement in conversions. At higher spend levels, the data becomes noisier — more money, more unpredictability.

More striking is the efficiency gap between the platforms. Instagram consistently generated higher conversions at comparable or lower spend levels than Facebook. For advertisers operating under tight margins — as gym franchises often do — that gap is significant. It suggests that Instagram campaigns may deliver a stronger return per dollar, not because of anything inherently superior about the platform, but because its ad environment may be better suited to the fitness audience being targeted.

The pattern points to diminishing returns that marketers are often reluctant to acknowledge: after a certain threshold, scaling ad spend does not scale results.

The click-through rate paradox

Perhaps the most counterintuitive finding involves CTR — the metric many advertisers treat as a primary indicator of campaign health. High click-through rates are typically celebrated as a sign that an ad is resonating. The data suggests that celebration may be premature.

The interpretation is straightforward but uncomfortable. High CTR often reflects broad, attention-grabbing creative that appeals to a wide audience — including people with no real intention of signing up for a gym membership. Lower CTR campaigns, by contrast, may be reaching a narrower but more genuinely interested audience, one that is more likely to follow through.

Facebook showed more variability in this relationship, with occasional outliers achieving both low CTR and high CVR — a sign that well-targeted campaigns can still perform strongly. Instagram’s pattern was more consistent, even if it followed the same downward trend.

The bottom line

Taken together, the findings paint a clear picture of where social media advertising strategy goes wrong. The instinct to maximize — more impressions, more spend, more clicks — consistently fails to translate into more conversions. The metrics that dominate campaign dashboards are, at best, loosely connected to actual business outcomes.

Between the two platforms, Instagram emerges as the stronger performer for this category of advertiser. It offers greater cost efficiency, more consistent conversion behavior, and less susceptibility to the diminishing returns that plague high-spend Facebook campaigns. Facebook retains value as a reach vehicle, but its inconsistency demands more careful optimization to yield results.

For gym brands — and likely for many advertisers in similarly competitive, consumer-facing categories — the data makes a pointed argument: the goal should not be to reach the most people or generate the most clicks, but to reach the right people with enough precision that every dollar and every impression counts.