Losing weight while maintaining your strength, from the very beginning: why moving changes everything

Physical activity, obesity medications and motivation: we need to change the way we think about movement.

Why physical activity isn’t just about burning calories and how to get back on track when you’re tired, in pain, or not very sporty.

One of the phrases I hear often in consultations is:

« I will start exercising when I lose some weight. That will be easier. »

And that’s perfectly understandable.

When you live with a heavier body, fatigue, joint pain, shortness of breath, or simply years of inactivity, then the idea of starting to exercise may seem daunting.

For a long time, we have often thought in this way: let’s start by helping with weight loss. When the person is lighter, they will be able to move more.

Today, our approach to physical activity in the treatment of obesity is evolving.

With modern treatments for obesity, such as GLP-1 medications, gastric balloons, or dietary replacements, weight loss can be significant and relatively rapid.

When we lose weight, we don’t just lose fat.

The body can also lose muscle. And we want to protect that muscle. from the very beginning of the weight loss.

Physical activity is not primarily about «burning off» the kilos.

We have long been presented with a very simple equation:

I eat → I accumulate calories.
I exercise → I burn calories.
So I have to exercise more to lose weight.

This view is too simplistic and it is sometimes guilt-inducing.

Yes, physical activity increases energy expenditure. But in a normal life, the amount of exercise that most people can reasonably achieve usually produces a fairly modest weight loss when used alone.

Because physical activity doesn’t need to bring the scale down to be effective.

It improves cardiovascular health, mobility, insulin sensitivity, metabolic health, strength, and quality of life. It also contributes to bone health and the prevention of many chronic diseases.

And when you’re trying to lose weight, physical activity has another fundamental function:

protect our muscles.

When the balance tilts, what are we really losing?

Ten kilos less on the scale does not necessarily mean ten kilos less fat.

Part of the weight lost may correspond to lean mass, including muscle.

This does not mean that new drugs «melt the muscles». A decrease in lean mass often accompanies significant weight loss, regardless of the method used.

But the more effective the treatments become and the faster the weight loss can be, the more we must ask ourselves at least two questions:

«How much have you lost?»

And also:

« How does your body change during this weight loss?»

Do you retain your strength? Your mobility? Your ability to climb stairs, get up from a chair, carry your bags, and walk for long periods of time?

One of the goals in obesity medicine is to promote fat loss while protecting as much as possible. muscles, strength and physical function.

And for that, walking is excellent… and you need to gradually work the muscles against resistance as well.

The muscle needs to know that you still need it.

The body is extraordinarily adaptable.

When a muscle is regularly subjected to stress, we send it a kind of message:

«This muscle serves me. I need it.»

This is the principle of muscle strengthening.

And it doesn't necessarily require dumbbells, machines, or a gym membership. Yet the weight of your own body already constitutes resistance.

To maintain this muscle, it is also necessary to provide it with enough protein. During a significant weight loss, Muscle activity and adequate protein intake therefore work together to help preserve lean mass.

This is particularly important as we age, when preserving our muscle capital becomes progressively more valuable. Nevertheless, we can build muscle at any age and it is better to protect the muscle we have than to wait until we lose it before we start to worry about it.

What science tells us

Physical activity is essential for health, but its effect on weight when used alone remains generally modest. European recommendations report an average weight loss of about 2 to 3 kg with aerobic exercise alone, While emphasizing its numerous cardiovascular, metabolic and functional benefits. Muscle strengthening is particularly recommended to preserve lean mass during weight loss.

With modern treatments for obesity, this question takes on even greater importance. A meta-analysis published in 2026 reports that lean mass accounted for approximately 25 to 39 % of the lost weight in studies using incretin-based treatments. This does not mean that these drugs «melt the muscles»: a loss of lean mass also accompanies the weight loss achieved through other methods. However, interventions combining lifestyle changes and Resistance training They had a lower proportion of lean mass loss.

The practical message is therefore simple: during a significant weight loss, protecting your muscles is part of the treatment. Progressive muscle strengthening, an adapted diet with sufficient protein intake and the maintenance of physical activity all contribute together to preserve lean mass, strength and physical function.

«Okay… but I’m tired and I have no motivation»

So don't start by saying «exercise».

Start by moving around.

There is a psychological difference between saying to oneself:

«Starting Monday, I have to do 150 minutes of exercise a week.»

and:

«Tomorrow morning, before my shower, I'm going to move for five minutes.»

No need for sports attire.
No need for gym.
No equipment required.

You can even stay in pajamas.

And if you took the pajama challenge: 5 exercises, 5 minutes to start over, what would change in your day?

Attention, before you start: if you suffer from a significant cardiovascular, respiratory or musculoskeletal disease, if you have problems with balance, unusual pain, marked shortness of breath or any other health problem that may limit your effort, or if you have not moved for a long time, talk to your doctor or healthcare professional before starting or intensifying physical activity.

1. Get up and sit down from a chair, 5 to 10 times
You work the thighs and buttocks, essential muscles for getting up, climbing stairs, and maintaining your independence.

2. Perform push-ups against a wall, 5 to 10 times
More accessible than floor pumps, they work the arms, shoulders, chest and trunk.

3. Walk around the place for 30 seconds to 1 minute
Alternate lifting your feet or knees as you are able. If necessary, hold onto a chair.

4. Stand on the tips of your feet, 10 times
Go up slowly, then come down slowly. A simple exercise for your calves, ankles and balance.

5. Waking up the deep muscles of the abdomen, 5 slow breaths
Lying on your back, knees bent, or standing, place one hand on the lower abdomen. Inhale calmly, then exhale slowly by gently contracting the lower abdomen, as if you were to slightly bring your navel closer to your spine. Continue breathing normally, without blocking your breath or forcing it. Release, then begin again.

The transverse plane is involved in controlling the trunk and posture. Thus, exercises inspired by Pilates are indeed an excellent way to gradually work on breathing, trunk control, mobility, and deep muscles.

And after the first five minutes?

5 exercises and that’s it for today

It may have taken you five minutes.

And five minutes count.

When these five minutes become easy, don't necessarily try to go much faster: gradually add a few repetitions, a second round of the series, or a little resistance.

It is this progression that allows the muscle to continue adapting.

Motivation sometimes comes after the action.

We often expect to feel motivated to start.

But motivation doesn't always work that way.

It can also be built:

Small action → success → satisfaction → sense of competence → motivation → new action.

That is why the first objective sometimes has to be almost ridiculously easy — and, if possible, pleasant.

Five minutes today.

Then five minutes tomorrow.

Then ten.

The walk gets longer. The chair raises become easier. A few repetitions are added. Then an elastic band. Maybe a Pilates class. Maybe aquagym, cycling, dancing, walking, or finally a gym.

We progress based on where we are, not where we think we should already be.

Finding what prevents you from moving

When someone tells me: «I lack motivation», my next question is often:

What makes the movement difficult for you today?

The answer is not always motivation. However, it can be pain, fatigue, fear of injury, shame about one’s body, a bad experience with sports, lack of time, the belief that physical activity is only useful if it is intense, or simply the difficulty in turning an intention into regular behavior.

In consultation with obesity medicine, At the CoAttitude clinic, I work with each person to identify the obstacles that make movement difficult, in order to build a gradual, realistic, and adapted physical activity program that is appropriate for their abilities, pain, and pace.

Pain deserves to be evaluated and treated. When medications are necessary, we can also take into account, when possible, their impact on weight and fatigue.

Coaching and cognitive-behavioral therapy can help to define goals that are small and concrete enough to become achievable, to track progress, and to gradually build a new routine.

Hypnotherapy can also be used as a complementary tool to work on certain representations of the body and movement, resistances, automatisms or The difficulty in moving from intention to action.

The first goal for the physical movement is therefore not to become a sports person.

It’s about regaining confidence in your body and your ability to move.

And what if my weight doesn't go down anymore?

It is here that it is important to recall a reality: Obesity is a chronic disease.

We do not entirely choose the weight at which our body will arrive, nor the one it will be able to maintain over time.

The biology of weight is complex. It depends, in particular, on genetic, hormonal, metabolic, environmental, and neurobehavioral factors.

After weight loss, the body can activate physiological defense mechanisms: increased appetite, hormonal changes, and reduced energy expenditure. This is why these mechanisms, inherited from our biological ability to protect ourselves against food shortages, can promote weight regain.

So it’s not simply a matter of will.

Physical activity does not eliminate this biology.

It does not guarantee a specific weight or the absence of weight gain.

And I find it important to say it, because Moving should never become a new way of blaming someone whose weight doesn’t respond the way they hoped it would.

The movement brings us something much more reliable than the promise of a figure on the balance sheet.

It allows us to act on the health and the capabilities of the body that we have today.

Moving towards something other than the balance

So, when you start an obesity treatment, don’t just measure your progress in kilograms.

Also ask yourself:

How many floors are easier to climb?
Do I get up more easily from a chair?
How is my breath on the walk?
Do I feel stronger?
How can I recover better after an effort?
Do I have more confidence in my body?
Can I do something today that was difficult three months ago?

These are also results of the treatment.

And sometimes, they are the ones who count the most in everyday life.

New treatments for obesity now allow us to achieve weight loss that was once difficult to achieve. But our goal cannot be solely to create a slimmer body.

In obesity medicine, we want to help the person live in a body. stronger, more mobile, more functional and healthier, Whatever the figure ultimately appears on the balance sheet.

So don’t wait to lose 10 or 20 pounds before you start.

Start small and gradually increase.

Start slowly.

Start in your room if necessary.

Start even in pajamas.

Your goal today isn’t to do too many things. Don’t do too many things. It’s more important to do enough things that you’ll want to do them again tomorrow.

And while your weight is changing rapidly, slowly, or sometimes very little, keep sending your body a message that remains relevant:

«My muscles serve me. My mobility matters. My health matters. So I move to take care of the body I have today.»

References

Oppert JM et al. Exercise training in the management of overweight and obesity in adults: Synthesis of the evidence and recommendations from the European Association for the Study of Obesity Working Group on Physical Activity. Obesity Reviews, 2021.

Locatelli JC et al. Incretin-Based Weight Loss Pharmacotherapy: Can Resistance Exercise Optimize Changes in Body Composition? Diabetes Care, 2024.

Lean Mass Changes With Incretin Therapy Versus Lifestyle Intervention: A Systematic Review and Meta-Analysis of Randomized Controlled Trials. Diabetes, Obesity and Metabolism, 2026.