Hi there,
Thanks for reaching out regarding your Facebook Ads issue with your gym apparel client. I thought I could offer some initial thoughts and guidance. It’s a really common situation to be in, and honestly, what you’re seeing isn’t that strange at all. It's actually a classic case of fighting the algorithm instead of working with it.
You’ve stumbled onto something that trips a lot of people up: the idea that your own logic about who *should* be a customer is better than the mountain of data the Meta algorithm has at its disposal. You think you're helping by giving it "super relevant" interests, but in reality, you're probably just tying its hands behind its back. Let's get into why that is and what you can do about it.
We'll need to look at why 'Broad' is beating your 'Interests'...
First off, you need to trust the data. Your test was perfect: you removed the interests, sales went up 50%. You put them back, sales dropped. The evidence is staring you right in the face. The issue isn't that the interests are "counter productive," it's that your assumption about them being necessary is flawed.
When you set up a campaign with a sales or conversion objective and go broad (with only age, gender, location), you're giving the algorithm a simple, powerful command: "Here is my ad, here is my pixel data from past purchasers, now scan this entire country and find me the people who look and act most like my existing customers and are most likely to buy my stuff right now." It's an incredibly effective instruction.
The algorithm can see millions of data points that you can't. It might know that people who buy your client's type of gym wear also happen to be obsessed with a particular cooking show, follow a specific travel influencer, and buy a certain brand of coffee. These aren't connections you'd ever make. It sees patterns in behaviour, purchase history, and on-platform activity that predict a sale.
When you add in your "super relevant" interests, you change the command to: "Find me people who are likely to buy, but you are ONLY allowed to look in this little pond I've designated." You've taken away its biggest advantage – its massive reach and data-processing power. You're forcing it to ignore all those potential customers who love cooking shows because they don't also have "Weight training" listed as an interest on their profile. You're paying the world's most powerful advertising machine to find customers, and then telling it exactly how to do its job. It's almost always going to be better at it than you are.
This is especially true once your pixel has seasoned and gathered enough data. For a brand new account with no data, interests are a good place to start. For an account that's been running for months, you should be leaning on the pixel's intelligence, not your own hunches.
I'd say your view of a 'relevant interest' is probably the problem...
Let's be brutally honest about interest targeting. It's often a complete nightmare and not nearly as specific as you think. Forget the sterile, demographic-based profile. You need to define your customer by their pain, not by the pages they've liked.
What interests are you actually using? I'd bet they're things like "Fitness and wellness," "Gymshark," "Bodybuilding," or "Activewear." On the surface, they seem perfect. In reality, they are terrible.
-> Targeting "Gymshark": You're now paying to show your ads to a huge group of people who are either die-hard Gymshark loyalists, have just bought new gear from them, or are just browsing. You're putting your client, likely a smaller brand, in a direct comparison with a market leader on their home turf. It's an uphill battle.
-> Targeting "Fitness and wellness": This is a bucket with tens of millions of people in it. It includes everyone from serious athletes to people who just liked a post about "5 easy yoga poses" once. It's far too broad to be meaningful, and you're paying to reach a huge number of people who will never buy performance gym apparel.
The trick is to think about the *problem* your client's apparel solves. What is the specific, urgent frustration their ideal customer has?
Once you define that *nightmare*, you can find much smarter interests. For instance, if it's for serious lifters, you could try targetting followers of specific powerlifting federations, niche equipment brands (like Eleiko or Rogue Fitness), or even specific coaches known in that world. These are interests that a casual fitness fan is much less likely to have. This is how you find your real audience.
You probably should rethink your entire account structure...
Just switching interests on and off in a single ad set isn't a long-term strategy. It sounds like you need a proper, professional campaign structure. This allows you to speak to people differently depending on how familiar they are with the brand. It's what we do for all our eCommerce clients, and it makes a huge difference. I've seen it work for a women's apparel brand we work with, which saw a 691% return once we got the structure right.
You want to think in terms of a funnel: Top (ToFu), Middle (MoFu), and Bottom (BoFu).
1. ToFu - Cold Prospecting Campaign
This is for reaching people who have never heard of your client before. This campaign's job is to find new customers. It should be a Campaign Budget Optimisation (CBO) campaign where you test different audiences against each other. Your broad ad set lives here, and it should be your workhorse.
Here’s a sample structure for your ToFu campaign:
| Ad Set Name | Audience Targetting | Purpose |
|---|---|---|
| 01 - Broad (UK - 25-45 M/F) | No interest or lookalike targeting. Just age, gender, location. | Your proven winner. Let the algorithm find buyers in the general population. This should get a good chunk of the budget. |
| 02 - LAL 1% - Purchasers | Lookalike (1%) of all customers who have purchased in the last 180 days. | Finds the people who most closely resemble past buyers. Usually a top performer once you have enough data (at least a few hundred purchases). |
| 03 - LAL 3% - Add to Cart | Lookalike (3%) of everyone who has added a product to their cart. | A slightly broader lookalike, good for scaling. Captures people who showed high intent but might not have converted yet. |
| 04 - Interest Stack - The 'Nightmare' | A stack of those *smarter* interests we talked about. E.g., Niche equipment brands + specific fitness event pages + niche fitness publications. | A test to see if a carefully curated interest audience can compete with the algorithm's broad approach. |
You let CBO manage the budget, and after a week or so, you'll see where the money is flowing. You turn off the losers and keep the winners, then introduce new audience tests.
2. MoFu/BoFu - Retargeting Campaign
This is where you make a ton of your money. You're leaving sales on the table if you aren't doing this. This campaign targets people who have already interacted with the brand but haven't bought yet. These are your warmest leads.
Your audiences here would be:
-> All Website Visitors (Last 30 Days)
-> All Instagram/Facebook Engagers (Last 90 Days)
-> Viewed Content / Product Page Visitors (Last 14 Days)
-> Added to Cart (Last 7 Days) - *Exclude Purchasers*
-> Initiated Checkout (Last 3 Days) - *Exclude Purchasers*
The messaging here is completely different. For a website visitor, you might show them a carousel of best-selling products. For someone who abandoned their cart, you show them the exact product they left behind, maybe with a message like "Still thinking it over?" or even a small discount code like "Come back and get 10% off" to push them over the edge. This structure organises your efforts and ensures you're sending the right message to the right person at the right time.
You'll need a message they can't ignore...
Even with the best targetting in the world, your ads will fail if the creative is weak or the offer isn't compelling. For gym apparel, you have to sell the outcome, not the product.
Don't just say: "Our new seamless leggings."
Say: "Tired of leggings that roll down mid-squat? Our new seamless collection stays put, so you can focus on your PB, not your waistband."
Don't just show a static photo of a t-shirt.
Show a video of someone drenched in sweat after a brutal workout, with the t-shirt still looking great and not clinging uncomfortably. You're not selling cotton; you're selling the feeling of being a dedicated athlete.
This also extends to your product pages. What happens after the click?
You need to analyse the whole journey. A great ad pointing to a poor website will always fail. Your client's site needs to scream trustworthiness: high-quality photography (on actual people, not just flat lays), clear product details, customer reviews with photos, an easy returns policy. Without these, people won't feel comfortable handing over their card details.
Finally, you need to know what a customer is actually worth...
This is something almost no one running ads for smaller clients thinks about, but it's the most important metric of all. You're worried about performance, but do you even know what good performance looks like? You need to know the customer's Lifetime Value (LTV).
The real question isn't "Why are my ads not working?" but "How much can I afford to spend to acquire a customer?"
Let's do a quick, rough calculation for a brand like this:
Average Order Value (AOV): What's the average first purchase? Let's say it's £70.
Purchase Frequency: How often does a customer buy per year? Maybe 2.5 times.
Customer Lifetime: How many years do they stay a customer? Let's be conservative and say 2 years.
Gross Margin %: What's your client's profit margin? Let's say it's 60%.
LTV = (AOV * Purchase Frequency * Customer Lifetime) * Gross Margin
LTV = (£70 * 2.5 * 2) * 0.60
LTV = £350 * 0.60 = £210
In this rough example, each new customer is worth £210 in gross profit to the business. A healthy ratio for growth is a 3:1 LTV to Customer Acquisition Cost (CAC). This means you can afford to spend up to £70 to acquire a single new customer and still have a very healthy, profitable business.
Does that £70 CPA suddenly make those "mediocre" sales look different? This is the math that unlocks scale. It stops you from panicking and turning off campaigns too early. When you know you can spend £70 to make £210, you can advertise with confidence.
This is the main advice I have for you:
To pull this all together, here's a summary of what you should be focusing on. This is a strategic shift, not just a quick fix.
| Area of Focus | The Problem | Recommended Action | Why It Works |
|---|---|---|---|
| Prospecting Strategy | Over-reliance on flawed interest targeting and fighting the algorithm. | Prioritise broad targeting in your main prospecting campaign. Trust the data that showed a 50% sales lift. | Leverages the full power of the Meta algorithm to find buyers you would never think to target manually. |
| Account Structure | A flat structure, likely one campaign or ad set trying to do everything. | Implement a ToFu/MoFu/BoFu funnel structure with separate campaigns for prospecting and retargeting. | Allows you to scale efficiently and deliver the right message to the right user at the right stage of their journey. |
| Audience Testing | Testing interests vs no interests, but not testing the most powerful audiences. | Within your ToFu CBO, start testing high-quality lookalikes (Purchasers, Add to Cart, etc.) against your broad audience. | Lookalikes find new customers who mirror the behaviour of your most valuable existing users, often outperforming interests. |
| Retargeting | Likely leaving money on the table by not systematically retargeting warm leads. | Build a dedicated retargeting campaign targeting cart abandoners, site visitors, and engagers with specific 'closing' ads. | This is the lowest-hanging fruit for increasing sales and ROAS, converting users who are already close to buying. |
| Financial Metrics | Operating without knowing what a customer is worth, leading to poor decisions. | Calculate your client's LTV to establish a target Customer Acquisition Cost (CAC). | Frees you from the tyranny of 'cheap' conversions and allows you to invest confidently in acquiring high-value customers. |
As you can see, the problem goes a bit deeper than just which interests to select. It’s about a fundamental shift in how you approach the platform. Getting this right involves building a robust structure, constant testing, analysing data, and understanding the core business metrics that drive growth. It's not just setting up an ad and hoping for the best.
This is where professional help can make a huge difference. An expert can implement this entire strategic framework for you, manage the testing and optimisation process, and ensure every pound you spend is working as hard as it possibly can to grow the business. It takes the guesswork out of it and replaces it with a proven process.
We do this for our clients every day. If you'd like to chat through this in more detail and have us take a proper look at your client's ad account, we offer a free, no-obligation strategy session. We can audit what you’re doing and give you a clear roadmap for what to do next.
Hope that helps!
Regards,
Team @ Lukas Holschuh
