The Sunk Cost Fallacy: Why Your Past Failures Are Stopping You from Succeeding

Don’t let your past mistakes keep you from reaching your future goals—here’s why the Sunk Cost Fallacy is holding you back and how to break free

Ever find yourself thinking, “I’ve already tried everything, so why would this time be any different?” Or maybe you’ve felt like the effort you’ve put into failed attempts at getting fit means you’re just not cut out for it.

That’s the Sunk Cost Fallacy messing with your head. It’s when your brain tricks you into thinking that just because you’ve invested time, effort, or money into something, you can’t walk away—even if it’s not working. You get stuck in this loop, letting past failures convince you that future success isn’t possible.

But here’s the thing—those past attempts? They’re irrelevant now. What matters is that you don’t let them dictate your next steps. You’re not doomed to repeat the past, but you are at risk of staying stuck in it if you keep letting the Sunk Cost Fallacy rule your decisions.

Let’s break down how this psychological trap works and, more importantly, how you can escape it to finally move forward with your fitness goals.

Tip #1: Understanding the Sunk Cost Fallacy—Why Your Brain Won’t Let Go

The Sunk Cost Fallacy comes from behavioral economics and psychology. It’s the idea that we irrationally hold on to things simply because we’ve already invested in them—even if continuing down that path is a bad idea.

Daniel Kahneman, the Nobel Prize-winning psychologist, explains that our brains hate the idea of wasted effort or time. So, instead of cutting our losses, we double down, thinking, “I’ve already put this much in; I can’t quit now.” The result? You stay stuck in a loop, wasting more time and energy on something that’s not working.

In the context of fitness, this shows up when you cling to past workout routines, diets, or approaches that failed. Instead of trying something new, you tell yourself, “If I couldn’t stick to it before, why bother now?”

The first step to breaking free is recognizing that the effort you’ve already put in doesn’t matter if the approach isn’t getting you closer to your goal. It’s time to let go and focus on what will actually work for you now.

Tip #2: Stop Letting Past Failures Define Your Future

Here’s the brutal truth: your past failures mean nothing about what you’re capable of going forward.

It’s easy to get caught in the mindset of, “I’ve failed before, so I’ll fail again.” But that’s just the Sunk Cost Fallacy talking. Just because one method didn’t work, or because you couldn’t stick to a plan in the past, doesn’t mean you’re doomed to fail again. Carol Dweck, the psychologist who pioneered the concept of the growth mindset, tells us that setbacks are not permanent—they’re part of the process.

Reframing how you see those failures is key. Instead of letting them define you, see them as stepping stones that taught you what doesn’t work. It’s not about how many times you’ve tried and failed. It’s about learning from those experiences and using that knowledge to find the approach that works for you now.

Tip #3: Why Stubbornness Can Keep You Stuck in a Bad Routine

Sometimes, sticking with something that isn’t working feels like the “right” thing to do—after all, persistence is often seen as a virtue. But when it comes to fitness, persistence in the wrong routine can be a huge mistake.

Psychologist Dan Ariely, who studies decision-making, explains that people often stay stuck because they don’t want to admit that their initial decision was wrong. This kind of stubbornness keeps you locked in a routine that isn’t delivering results.

You might feel like you’ve committed to a workout plan, spent money on a diet program, or invested time in a fitness app. But if you’re not seeing the changes you want, it’s time to stop digging. Doubling down on something just because you’ve already started won’t magically make it work.

Instead, allow yourself to pivot. Recognise when something’s not working and have the courage to try a different path, even if it means starting afresh.

Tip #4: How to Cut Your Losses and Move Forward

Breaking free from the Sunk Cost Fallacy means learning to let go of your emotional attachment to what didn’t work. The most successful people aren’t the ones who never make mistakes—they’re the ones who quickly pivot when something isn’t serving them.

Here’s how to do it:

  1. Acknowledge the investment, but don’t let it weigh you down. Yes, you’ve put in time and effort, but continuing down the wrong path will only cost you more in the long run.
  2. Focus on future gains. Behavioral science shows that we’re more motivated by the fear of losing what we already have than by the prospect of gaining something new. Flip this on its head. Instead of obsessing over what you’ve lost, focus on what you can gain by changing your approach now.
  3. Adopt a growth mindset. Instead of seeing your past attempts as failures, see them as learning experiences.

Tip #5: A New Approach Means a New You

So what’s the solution? It’s simple: stop dragging your past into your future. Every new attempt at fitness is a fresh opportunity. You’re not stuck with the baggage of old routines that didn’t work. You have the power to try something new, something built for who you are today, not who you were before.

Ask yourself, “What will help me move forward right now?” It might mean trying a new type of workout or building healthier habits around your current life situation. Whatever it is, don’t let your past investments in failed plans keep you from exploring what could actually make you stronger, fitter, and happier.

The way forwards

The Sunk Cost Fallacy is sneaky—it convinces you that because you’ve put effort into something, you’re trapped. But the reality is, those past failures mean nothing about what you can achieve now. Let go of the things that didn’t work and open yourself up to new possibilities.

Your fitness journey isn’t about clinging to the past. It’s about what you do next. Stop letting sunk costs keep you from success.

It’s time to move forward.