The Weight Loss Mistake Everyone Makes: Too Much Cardio, Too Few Calories

You’ve been there before, right? Eating salads so dry they make cardboard look gourmet, sweating through endless hours on the treadmill, and all for what? A scale that seems to have a

personal vendetta against you. Losing weight can feel like trying to solve a Rubik’s cube while blindfolded. The advice is everywhere: “Just eat less and move more!”. But here’s the kicker: slashing calories and doubling down on cardio often does more harm than good. This isn’t to say you’re doing anything wrong; your efforts come from a place of dedication and wanting to feel your best. But the truth is, the approach most people swear by isn’t just ineffective—it can actually sabotage your progress. In this post, we’re diving into why “eat less, run more”

isn’t the magic formula and, more importantly, what to do instead.

1. The Problems with Simply Cutting Calories

So, what’s the issue with drastically reducing your daily calorie intake? Unfortunately, your body doesn’t care about your beach physique. I know that’s tough, but what it’s focused on is survival. For all intents and purposes, it’s as if you’ve been stranded in the wilderness with limited food. Now, your body has three options: it can tap into a reserve supply stored within you at all times, which is body fat; it can reduce your energy demands by making you lethargic, reducing fidgeting, and generally making you more subdued; or it can combine these two strategies. Since your body is uncertain about the duration of the food shortage, it’s likely to employ a combination of these approaches to sustain itself as long as possible. Imagine your salary is cut, leaving you unable to cover all your bills and food expenses. You’d have to cut back on unnecessary spending and turn to savings.

You might think, “I’m turning to my fat stores for energy,” which is true. But as your energy needs decrease, you’ll need less energy from fat stores. Your body will also do something that harms fat loss and makes it harder to prevent muscle regain. Muscle needs calories, while fat stores don’t. Unless your body has a reason to keep it, it’ll make it too expensive to maintain all your muscle. Your muscles can be converted into energy, reducing the energy needs from lost muscle. Imagine downgrading your Netflix subscription when your salary gets cut. This leads to a downward spiral of eating less, losing more muscle, and needing to eat less to maintain fat loss, resulting in more muscle loss. Preventing fat gain when you start increasing calories at the end of your fat loss journey is problematic. You have less muscle, so your energy needs are lower than they would have been if you hadn’t lost any muscle. Consequently, the amount of energy you can consume before storing leftover energy as body fat will be reduced. This means you have to eat less food, making it harder to stick to your diet.

Okay, so we know that cutting calories too much is a bad idea for continued fat loss and for maintaining that body fat in the long run. Unfortunately, it doesn’t end there…

Because you now need to consume fewer calories to maintain any fat loss, you have significantly fewer calories to play with. One crucial food type to consume enough of to prevent muscle loss is protein. Surprisingly, it’s important to eat even more protein to prevent muscle loss when we’re in a calorie deficit than when we’re trying to build muscle. However, we have fewer calories to accommodate the increased protein intake. This may necessitate sacrificing foods rich in healthy fats, vitamins, and minerals, which can lead to further negative consequences such as reduced testosterone production, which supports muscle building and fat loss; reduced oestrogen production, which aids in regulating reproductive systems, maintaining bone density, and supporting heart health; a weakened immune system; and fatigue.

And there’s more!

Reducing calories too rapidly can decrease leptin, a hormone that promotes satiety; increase ghrelin, a hormone that stimulates hunger; increase cortisol (the stress hormone), which can lead to burnout; impair insulin levels; and impair growth hormone. These factors can hinder fat loss, recovery, and muscle repair.

2. The Downsides of Overdoing Cardio

So we have talked about why reducing calories too quickly is not a good idea, but what about doing too much cardio or relying solely on cardio for fat loss.

Lets say you haven’t been exercising lately, have lost some of your fitness, and have put on a few pounds to the point that you are no longer happy with how you feel. You have decided to start doing cardio, and to start with, it’s really hard work and burns a heap of calories. This is awesome, but… your body starts to adapt to this and makes you fitter, which is amazing for your overall fitness levels and your overall health, but this increase in fitness means that you now need less energy to do the same amount of exercise, and therefore you need to increase the amount of exercise that you do. Either this may not be possible due to time constraints, or the continued increase may lead to overtraining, which can cause chronic fatigue and increase the risk of injury. There is also the risk of psychological burnout. Knowing you have to regularly turn up to complete long durations of cardio to maintain fat loss can be extremely hard to sustain. I have lost count of the amount of people who I have seen in a gym who turn up every day for about 3-4 weeks, do lots of cardio, and work really hard, but then disappear, and I don’t see them again for months or even years before they start the same process again.

Now, let’s imagine that you are driving a car on a journey that is 100 miles, but you only have enough fuel for 70 miles. How fast you get there really doesn’t matter, and the only thing that matters is that you reach your destination. Your car has a 3-litre engine and is large in size but delivers a lot of power, but the problem is you can’t use that power because it will use too much fuel. Now let’s say that you have the option of downsizing your car both in physical size and its engine size, which then lets you complete your journey. Well, this is essentially what happens when you only do cardio and don’t do any resistance training, such as weight training. Because you are not regularly telling your body that you need that muscle and that it is important to keep around, your body will start to swap that muscle for energy, which essentially gives you a smaller engine and, of course, a smaller frame. However, as we have already mentioned, this means you now need less fuel all the time!

Finally, focusing solely on cardio can lead to other critical factors such as nutrition quality, sleep, and stress management being overlooked, all of which can have huge impacts on the success of your fat loss journey.

3. What to Do Instead: Smarter Weight Loss Strategies

So if cutting calories and endless cardio aren't the answer, what is? The key is a more holistic, intelligent approach to fat loss that works with your body, not against it.

Finding the Right Calorie Deficit

Not all calorie deficits are created equal. The goal is to find that sweet spot where you're creating just enough of a calorie deficit to promote fat loss without sending your body into survival mode. Research suggests that a moderate deficit of 10-20% below your maintenance calories is the magic window.

For most people, this translates to:

• Losing 0.5-1 pound per week

• Preserving muscle mass

• Maintaining energy levels

• Keeping hormones balanced

A too-aggressive deficit triggers all those survival mechanisms we discussed earlier: metabolic slowdown, muscle loss, and increased hunger. A moderate deficit, on the other hand, allows your body to tap into fat stores gradually while keeping your metabolism humming.

Resistance Training: Your Metabolism's Best Friend

As well as creating a suitable calorie deficit, the most powerful tool in your fat loss arsenal is resistance training. Unlike cardio, which can cause muscle loss, weight training sends a clear signal to your body: "This muscle is important, keep it!" By building and maintaining muscle mass, you're essentially upgrading your metabolic engine. More muscle means a higher resting metabolic rate, which means you burn more calories even when you're not exercising.

Nutrition: Quality Over Quantity

Instead of drastically cutting calories, focus on the quality of those calories. Prioritise:

• Lean proteins to support muscle maintenance

• Nutrient-dense whole foods

• Balanced macronutrients that keep you satiated

• Adequate hydration

A moderate, sustainable calorie deficit coupled with high-quality nutrition will yield far better results than extreme restrictions.

Incorporating Cardio Wisely

Cardio isn't the enemy—it's just been miscast as the lead actor in your fat loss story. Instead, think of it as a supporting character that brings additional health benefits. The key is to use cardio strategically:

• Prioritise low to moderate-intensity steady-state cardio

• Use it for heart health, not primary fat loss

• Mix in some high-intensity interval training (HIIT) for metabolic benefits

• Limit cardio to 2-3 sessions per week

• Never let cardio replace resistance training

Recovery and Stress Management

Often overlooked, recovery is crucial. This includes:

• Getting 7-9 hours of quality sleep

• Managing stress through techniques like meditation or yoga

• Allowing adequate rest between workouts

• Listening to your body's signals

Your hormones play a massive role in fat loss. Chronic stress, poor sleep, and overtraining can disrupt hormones like cortisol, insulin, and leptin, making fat loss an uphill battle.

4. The Long Game: Sustainable Transformation

Fat loss isn't about quick fixes or punishing yourself. It's about creating a lifestyle that supports your health and fitness goals. This means:

• Being patient with your progress

• Celebrating non-scale victories

• Understanding that consistency trumps perfection

• Creating habits you can maintain long-term

Conclusion: Your Journey, Your Transformation

Remember that initial frustration with dry salads and endless treadmill sessions? Your body isn't working against you—it's working to keep you alive and healthy. While it may feel great to see the number on the scales dropping quickly, and while many might congratulate you for such rapid progress, the truth is that a short-lived, aggressive approach often means the destination is never truly reached.

Instead, think of your fitness journey as a one-way path of continuous improvement. The duration of the journey is less important than the consistent, compassionate steps you take. This isn't about getting a perfect body in 30 days. It's about progressively becoming a healthier, stronger version of yourself.

By understanding your body's mechanisms and working in harmony with them, you can achieve sustainable fat loss without the misery. Ditch the extreme version of "eat less, run more" mentality and embrace a smarter, more compassionate approach to your fitness journey. Your body is your ally, not your adversary—and together, you can create lasting, meaningful change.