Why cardio isn't very smart if your goal is to lose weight

Have you been exercising for several weeks but aren't seeing any results on the scale?

You're not alone. Many people spend a lot of time running, spinning, or other cardio workouts – but their bodies don't respond as they hoped. It can feel both frustrating and confusing.

Don't get me wrong: cardio is great for your heart, brain, and overall health. But as a weight loss strategy? It has several biological drawbacks that often make it harder than you think.

Here are five reasons why it is wise to rethink:

1. You're not burning as much as you think

A common myth is that you can “run away” excess fat. But a 45-minute run often burns around 250–300 calories – about the same as a smoothie or a handful of nuts.

Research shows that people often overestimate their energy expenditure by up to 40–50%. This is especially true for overweight people, who tend to both overestimate their exercise and underestimate their calorie intake (PMID: 1454084). This means that you unknowingly eat more than you burn – which slows down or even reverses weight loss.

2. Exercise can increase appetite

When you exercise a lot – especially cardio – your body’s natural hunger regulation system is activated. The hormone ghrelin (which increases appetite) rises, while leptin (which signals satiety) can drop. This is a completely normal, biological response to increased energy expenditure.

The result? You feel hungrier, snack more – often without thinking about it – and find it harder to create a sustainable calorie deficit.

3. The body adapts and saves energy

What is called “metabolic adaptation” means that the body responds to increased energy expenditure and reduced food intake by lowering its basal metabolic rate. It simply becomes more energy efficient – a clever survival mechanism, but problematic when it comes to weight loss.

This means you burn fewer calories at rest, making it harder to lose weight even if you “do everything right.”

4. Increased stress can negatively affect hormones

Cardio training itself is a stressor for the body – and when you combine it with low energy levels, little sleep and everyday stress, levels of cortisol (the stress hormone) can rise chronically. High cortisol is linked to:

Increased fat storage, especially around the abdomen
Greater sweet cravings
Poorer recovery and sleep
Decreased muscle mass

These are factors that both worsen body composition and inhibit long-term results.

5. Hormonal influence – especially in women

For women, too much cardio combined with too little energy can disrupt hormone balance. Estrogen and progesterone can drop, which negatively affects metabolism, mood, and recovery. In some cases, menstruation can be affected.

For men, the consequence can be lowered testosterone, fatigue, reduced muscle mass and lower motivation.

What should you do instead?

It's not about stopping training – it's about training smarter and building a foundation that the body responds positively to.

A better strategy for sustainable weight loss:

Strength train 2–3 times a week – build muscle, improve body composition and increase resting metabolism.
Move more in your everyday life – walk, cycle, take the stairs. It doesn't stress the body but increases metabolism.
Eat nutrient-dense, protein-rich foods – it helps you stay full, preserve muscle and regulate blood sugar.

Do you want help getting started?

Our popular Summer Boost program starts on July 1st – an effective and sustainable 30-day kickstart with a focus on diet, exercise, hormone balance and fat burning. Perfect for those who want to see results without destroying their body with calorie restriction and overtraining.