Lose Weight Fast: Which Is More Important, Exercise Or Diet?

This article is for those who stay tuned and want to lose weight quickly.

“Be careful, exercise can make you fat!” I read it recently in a forum.

“Nonsense”, writes another, “you can only achieve the best progress with a lot of training!”

Who is right? One thing is certain, the discussion is ancient:

What is more if you want to lose weight quickly: training or diet?

Why is there training vs. Diet debate actually?

The fact that training helps you lose weight is obvious – one would think. In fact, the debate keeps coming up.

Why is that?

There are people who train regularly and still do not lose weight.

Some clinical studies show that people who want to lose weight lose weight at different rates – even though they follow the same exercise program.

That would be an argument in favor that exercise is not the decisive factor in fat loss. Or that people can break down fat differently.

Often, however, what is interesting about studies is what was not investigated.

Here, for example, eating behavior.

Further studies then uncovered the real cause:

Some people eat more when they exercise. Others don’t.

Scientists call the first group “expansion joints”.

Some compensators ate more because exercising gave them an appetite. For some, it was purely psychological: they thought that training had earned them an extra helping of food. 1

Another reason is that many people overestimate the calories burned during conventional endurance training. Moderate cardio training (walking or jogging) burns just 5-10 kcal per minute (or less).

30 minutes of jogging burns 150-300 kcal – about ½ bar of chocolate.

This frustrates some people because they expected twice or even three times as much.

Then imagine how easy it would be to take back the amount of calories you burned out during your next meal: a small piece of pizza, a beer or two, or a chocolate bar or two.

“Then I’d rather eat 500-1000 fewer calories a day”, many think, “I should be able to lose a kilo just as easily in 1-2 weeks.”

In a way, this may seem logical:

A significant calorie deficit can usually not be achieved in practice without a change in diet.

Let alone hold out.

And nutrition is not everything: when you lose weight, it’s not just calories that play a role. But also the positive changes that strength training triggers in the metabolism.

The blanket judgment that training is ineffective because you would have eaten too much afterwards therefore misses the target.

Things get clearer if we take a look at the fat burning formula.

Lose Weight Fast: What is the Fat Burning Formula?

If you want to lose fat, then you only have one chance:

You want to create an energy deficit.

However, the fat burning formula has two sides:

  1. Energy intake = Everything you eat.
  2. Energy consumption = training and movement

Note: I deliberately simplify because it is sufficient for the topic of this article. The daily calorie requirement is actually more complex than shown here.

There are easier ways than balancing diet and exercise.

Only when you use training AND nutrition to your advantage can you make optimal progress.

How do you find the optimal balance between training and nutrition?

Many people believe that they can lose weight quickly without exercising, expecting to lose 1-2 kilos of fat per week – just by eating less.

“After all, that’s exactly what the people doing on these weight loss TV shows,” they think.

But they usually don’t know what that would actually mean.

There is, for example, Anja 2, one of my personal coaching clients. Anja is in her early thirties, 1.73 m tall, 68 kilos, her body fat percentage was 23%.

In order to maintain her weight without exercising, she would have had to eat almost 1,800 calories a day.

If we calculate this using Anja’s starting coordinates, it quickly becomes clear how unrealistic even a kilo of fat loss per week would be through diet alone.

Case study # 1 – You would ONLY rely on nutrition

A kilogram of body fat provides around 7,000 calories.

If Anja wanted to lose a kilo a week, she would have to achieve a calorie deficit of 1000 Kcal a day. Since her energy requirement is 1800 kcal, she should only eat 800 kcal.

That would be a downright starvation diet that is doomed to failure for various reasons:

  • Feeling hungry: Anja would be permanently hungry and a steadily increasing appetite.
  • Vitamin deficiency : You eat far too little to supply your body with vital nutrients.
  • Fatigue : Your energy level would drop drastically, you would unconsciously move even less.
  • Muscle loss : Your body would not only break down fat, but also valuable muscles.

With this approach, she would have headed straight for the yo-yo effect. After stopping the starvation diet, she would have quickly put on additional fat.

Conclusion: Losing weight quickly is not a good idea without exercise.

Case study # 2 – You would ONLY rely on training

Now let’s say she kept her diet on but trained like a world champion.

To achieve the same calorie deficit, she would have to burn 1000 kcal every day just through exercise. How realistic are three hours of swimming or two hours of running or strength training – every day?

Even if we continue this thought:

  • Overtraining : A few extra hours of training overnight would be overwhelming even for professional athletes.
  • Stress : Anyone who dramatically increases their physical activity ad hoc will undoubtedly increase their stress level.
  • Injuries : Without sufficient regeneration, there is a risk of injuries to the musculoskeletal system.
  • Time spent : Anja could not have (let alone want to) the time for several hours of training a day in addition to a demanding job and time with friends.

Conclusion : Lose weight quickly ONLY with exercise? Not a good idea either.

Case study # 3 – You rely on training AND nutrition

I recommend Anja to include all four elements of the M.A.R.K.-formula and also to use it a little more moderately:

  • Objective : 500 grams of fat loss per week. That corresponds to a calorie deficit of 500 kcal per day.
  • Nutrition : 1,600 calories a day are just below her calorie requirement and Anja can easily convert them in everyday life. (By switching to protein-rich foods and lots of fresh fruit and vegetables, she is less hungry than before, despite the calorie deficit).
  • Training : Anja does strength training three times a week, which she complements with endurance training of her choice or regular walks. This enables her to increase her energy requirement by an average of 300 kcal a day.

With this approach, she lost a total of 4 kilograms of fat in 8 weeks – and felt great doing it. Of course you saw that.

What would have surprised you earlier: The scales have hardly changed during this time. But the body fat percentage has dropped significantly.

It’s good if you measure the right values.


If you want to lose weight quickly, then you should keep an eye on your energy balance.

In most cases it is not a good idea to focus solely on diet and eat fewer calories.

To maximize fat loss, you want to get your metabolism going and also work on the other side of the formula: your energy expenditure.

When you build muscle, you not only look more defined, you also use more energy while sleeping and on the sofa. More on this in this article. There you will also find out that proper training is more than just burning calories.

You also optimize your hormones to “slim and strong”.


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