There is a deep-rooted idea that to lose weight you just need to do cardio. Running, cycling, hours on the treadmill. And while cardio has its place, the science is clear: it is not the most effective strategy for long-term weight loss, and many people find that out the hard way, after months of effort with minimal results.
This article explains what really works when the goal is losing weight through exercise, and why functional and strength training is the approach with the most evidence behind it.
The most common mistake of people trying to lose weight with exercise
Most people who want to lose weight start with the same strategy: more cardio. More running, more treadmill, more bike. It's understandable: cardio burns calories in a visible, immediate way, and the logic seems simple.
The problem is that the body adapts quickly to cardio. Over the weeks, your body becomes more efficient at the same effort and burns progressively fewer calories doing the same run. The result is a frustrating plateau that makes a lot of people give up.
There is another factor that too much cardio without strength training does not fix: loss of muscle mass. When the body is in a calorie deficit without a strength stimulus, it tends to lose muscle as well as fat, which lowers your basal metabolism and makes it harder and harder to keep the weight off.
Why strength training is essential for weight loss
More muscle means a higher metabolism
Muscle is metabolically active: it burns energy even at rest. Every kilo of muscle you gain increases the number of calories your body burns each day, even when you're not training. Unlike cardio, which burns calories during exercise, strength training has an effect on your metabolism that lasts for hours and days after the session.
The afterburn effect
Strength training and high-intensity functional training cause what's called EPOC, Excess Post-exercise Oxygen Consumption. After an intense session, your body keeps burning more energy than usual for the following hours while it recovers and repairs muscle tissue. This effect is much more pronounced in strength and functional training than in moderate-intensity cardio.
Preserving muscle mass during a calorie deficit
When the goal is to lose fat without losing muscle, which is what really improves body composition and appearance, strength training is essential. Without a strength stimulus, a body in a calorie deficit has no reason to keep its muscle, and it loses it.
Functional training for weight loss: why it works so well
High-intensity functional training, like CrossFit or Conditioning, combines the best of both worlds: the high calorie burn of cardio with the strength stimulus that preserves and builds muscle.
A CrossFit session burns on average between 400 and 600 kcal per hour, comparable to intense cardio. But unlike cardio, it also stimulates muscle hypertrophy, which raises your basal metabolism and boosts fat loss in the long term.
On top of that, the constant variation of functional training (no two sessions are ever the same) stops the body from adapting and reducing calorie burn over time, which is exactly what happens with repetitive cardio.
The role of consistency in weight loss
No training method works without consistency. And consistency depends largely on keeping your motivation over time, which is much easier when you train in a group than when you train alone.
At Revolution Fitness, the structure of group classes with a coach present at every session creates exactly the environment that supports consistency. There's a set timetable, there are people expecting you and there's a coach who knows your goals. That makes a huge difference to sticking with it long term, which is the only factor that determines real results.
What exercise can't do on its own
It's important to be honest: exercise is a powerful tool for losing weight, but it isn't enough on its own. Diet is the most decisive factor in fat loss, not because exercise doesn't matter, but because it's much easier to create a calorie deficit through diet than through exercise.
The most effective combination is always strength or functional training together with a balanced diet in a moderate calorie deficit. Exercise preserves muscle, speeds up metabolism and improves body composition. Diet creates the deficit needed for fat to be used as fuel.
How long it takes to see results
Results depend on your starting point, consistency and diet, but there's a typical progression:
First 2 to 4 weeks: more energy, better sleep and better overall wellbeing. Your body composition starts to change, but the changes aren't very visible yet.
1 to 2 months: first visible results in body composition. Your clothes start to fit differently. Your performance in training clearly improves.
3 months onwards: consistent, measurable results. This is when most people start getting comments from those who haven't seen them for a while.
The key is not giving up in the first few weeks, when the results aren't visible yet but your body is already adapting.
How to start losing weight through exercise at Revolution Fitness
At Revolution Fitness you have several classes that fit a weight-loss goal:
CrossFit: high-intensity functional training that combines strength and conditioning. One of the most effective approaches to improving body composition.
HYROX: running and functional training combined. Excellent for anyone who wants to build cardiovascular endurance and strength at the same time.
Conditioning: high-intensity sessions focused on calorie burn and improving aerobic capacity.
Functional Bodybuilding: for those who want to improve body composition with a specific focus on building muscle.
Our certified coaches help you choose the right class for your goal and work out the ideal number of weekly sessions for you. Read our article on how many times a week you should train to see how to plan your week.
Your first class is free with no commitment. Book your session at revolutionfitness.pt, call 936 154 598 or send an email to geral@revolutionfitness.pt.
You'll find us at Pavilhão Hélio Cardoso, Rua Prof. Joaquim Augusto Silva, Figueira da Foz.
Frequently asked questions about losing weight with exercise
How many times a week should I train to lose weight?
For weight loss, 3 to 5 sessions a week is the recommended range. What matters most is consistency: training 3 times a week for months is far more effective than training 5 times for two weeks and then stopping.
Is cardio or strength training better for weight loss?
Combining the two is the most effective approach. Strength training preserves and builds muscle, which raises your basal metabolism and boosts fat loss in the long term. Cardio increases the calories burned per session. High-intensity functional training combines the benefits of both.
Can I lose weight without dieting?
Exercise contributes significantly to weight loss, but nutrition is the most decisive factor. It's very hard to create the calorie deficit you need through exercise alone without paying any attention to what you eat. Combining regular training with a balanced diet is always more effective than either on its own.
How long does it take to lose weight with functional training?
The first visible results usually appear between the 1st and 2nd month of consistent training. Significant changes in body composition typically show after 3 months. The pace depends on how consistent your training and diet are.
Is CrossFit good for losing weight?
Yes. CrossFit combines strength training with high-intensity cardiovascular conditioning, one of the most effective combinations for improving body composition. A CrossFit session burns on average between 400 and 600 kcal, with the added benefit of the afterburn effect, which keeps calorie burn going for hours after training.
