How Exercise Makes Losing Weight Harder
A Personal Trainer’s Take on a Common Fat Loss Mistake
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Introduction: You’re Exercising, But the Scale Won’t Budge
If you're exercising regularly, working hard in the gym, and still not seeing the weight loss results you're after… you’re not alone.
As a personal trainer in Bristol working with clients both in-person and online, I hear this all the time:
“I’ve been smashing the gym.”
“I’m doing cardio every day.”
“Why aren’t I losing weight?!”
It’s frustrating—and confusing. Especially when you feel like you’re doing everything right.
The truth is: exercise alone isn’t always the fat loss tool we want it to be. In some cases, it might actually make things harder.
Let’s unpack why that is—and what you should be focusing on instead.
1. Understanding TDEE: Where Exercise Fits in the Bigger Picture
Your body burns calories every day in a few different ways. This total is called your TDEE (Total Daily Energy Expenditure). It’s made up of:
🧠 BMR (Basal Metabolic Rate) – 60–70% of your daily burn
🚶 NEAT (Non-Exercise Activity Thermogenesis) – walking, fidgeting, standing
🏋️ Exercise Activity – what you do in the gym or in sports
🍔 TEF (Thermic Effect of Food) – calories used digesting food
Exercise typically only makes up 5–15% of your total energy expenditure.
Even a tough session in the gym might only burn 200–400 calories—which is easy to cancel out with an extra snack or two.
So while it feels like a big effort, exercise just isn’t that efficient at burning calories.
2. The Body Fights Back: Energy Compensation
Now here’s the kicker: your body often finds sneaky ways to “compensate” for all that exercise.
This might mean:
You unconsciously move less throughout the day
You sit more than usual post-workout
You feel hungrier—and eat more without realising it
A 2012 study published in Obesity Reviews highlighted how increased exercise can lead to increased hunger, reduced NEAT, and even reduced energy expenditure in other systems.
In other words, your body tries to protect itself from burning too much.
Another 2016 paper in Appetite found that individuals often eat back a large portion of the calories they burn from exercise—without knowing it.
3. Post-Workout Hunger Is Real
It’s not just about willpower—exercise literally makes you hungrier.
Especially high-volume cardio or long sessions, which can trigger a bigger appetite response.
Without clear awareness and nutrition tracking, this often leads to eating back the calorie deficit you worked hard to create.
This is one of the main reasons I encourage clients to build their deficit through diet, not just training.
4. Should You Stop Exercising? Absolutely Not.
Now, before you quit your workouts altogether—don’t.
Exercise might not be the best tool for fat loss, but it’s one of the most powerful things you can do for:
✅ Longevity and aging well
✅ Strength and injury resilience
✅ Mental health and stress relief
✅ Bone density and metabolic flexibility
✅ Habit stacking and routine
You just need to reframe your expectations.
Think of training as the thing that helps you build a body worth fueling well.
5. What You Should Focus On Instead
If your goal is fat loss, your #1 priority should be creating a consistent, manageable calorie deficit through nutrition.
Here’s how to do it smarter:
Track your food for a couple of weeks to establish awareness
Prioritise protein and fibre to stay fuller for longer
Plan meals and snacks ahead of time
Still train—but keep the focus on strength, movement quality, and long-term consistency
💡 *Strength training 2–3x/week and staying active with steps or general movement is more than enough for most fat loss goals—if the nutrition is dialled in.
Final Thoughts from a Personal Trainer in Bristol
Exercise is still essential—but it’s not a magic bullet for fat loss.
If you’ve been spinning your wheels in the gym, chances are… the issue is in the kitchen, not the squat rack.
At OPEX Bristol, we help people build fitness plans that actually work for their real life—without hours of cardio or unrealistic restriction.
If you’re based in Bristol and want to work with a coach, or you're looking for online support anywhere in the UK, we’ve got you.