• Any weight loss associated with physical activity will be greater if it is accompanied by dietary changes, according to our partner The Conversation.

  • Precision is all the more important as nearly one in two adults is overweight and one in six is ​​obese in France.

  • The analysis of this phenomenon was carried out by Alice Bellicha, lecturer in Nutriomics at the Sorbonne and Jean-Michel Oppert, head of the Nutrition department at the Pitié-Salpêtrière hospital.

Obesity is today, in France, a well-established and progressing disease.

A study carried out in 2020 established that nearly one in two adults is now overweight, and one in six is ​​obese (with, respectively, a body mass index [BMI] equal to or greater than 25 and 30 kg / m² - BMI corresponding to weight divided by height squared).

The body mass index is used to estimate the build of a person © Sankarip / Wikimedia CC BY-SA 3.0

However, there are accessible ways to help these people better control their weight and maintain their health: increasing their level of physical activity is one of them. However, while the effect of exercise on health is now widely accepted, its effect on weight management remains much debated, some even going so far as to say that it can make you gain weight.

We propose here to take stock of the real effects of exercise on food intake control, weight management and health.

For this, we rely on the expertise of the working group on physical activity and obesity, which we coordinated under the aegis of the European Association for the Study of Obesity (EASO).

Our group recently published physical activity recommendations for the management of overweight and obesity in adults.

The complex relationship between energy intake and expenditure

The more energy we spend on a daily basis, the more our food intake increases.

If the increase in energy expenditure is thus offset by an equivalent increase in energy intake, it is thanks to the sensitivity of our appetite control mechanisms.

This allows a majority of people to maintain a stable weight over time.

Unfortunately, these mechanisms that control food intake fail when energy expenditure, or physical activity, is too low.

In this case, even a small gap between energy intake and low energy expenditure can lead to gradual weight gain over time.

Lack of physical activity makes us more susceptible to “overconsumption” of food.

What happens when people who are overweight or obese participate in a training program?

To answer this question, Kristine Beaulieu and John Blundell, researchers at the University of Leeds in the United Kingdom, synthesized the results of 31 studies that compared energy intake before and during such a program.

The training (45 minutes of endurance activity) generated an energy expenditure of about 500 kcal per day, and participants reported an average increase in their food intake of 70 to 100 kcal per day.

Training therefore slightly increased food intake, but not enough to compensate for the additional energy expenditure caused by exercise: the energy deficit thus created promotes weight loss.

In a second review of the literature, we observed, in overweight and obese people, a weight loss of around 2 to 3 kg on average (but with notable differences) after several months of participation in a training program, but without specific dietary advice.

This loss was often less than their expectations, and can be considered negligible when obesity is significant.

It is therefore essential to inform these people that the expected weight loss with physical activity alone will not exceed a few pounds, but that it will be greater if physical activity is combined with changes in diet.

Among the foods that are less fatty and rich in energy to favor, we find of course vegetables, fruits, a little meat or fish, but also starchy foods: bread, lentils, rice, pasta… © Daria Shevtsova / Pexel

How to explain the energy deficit generated by exercise?

Three main mechanisms can be cited.

First, exercise strengthens the feeling of fullness (decreased hunger or desire to eat, for example during the hours after a meal).

Experimental studies have indeed shown that after a standardized food intake, people participating in a training program consume fewer calories at the next meal than untrained people.

Second, exercise seems to shift our food preferences toward foods that are lower in fat and energy.

Finally, exercise appears to improve certain parameters of eating behavior, in particular by reducing the feeling of loss of food control.

Weight loss isn't the only benefit of exercise

In this regard, Francesca Battista and Andrea Ermolao, doctors at the University Hospital of Padua in Italy, synthesized the results of more than 50 studies. They found that a few months of training is enough to improve several important cardiovascular risk factors in people who are overweight and obese: drop in blood pressure, improvement in sensitivity to insulin (a key hormone in blood metabolism). carbohydrates) and decrease in the amount of fat localized in the liver (intrahepatic adipose tissue). We have also shown a decrease in visceral fat tissue even in the absence of weight loss.

Marleen Van Baak and Adryian Pramono, from Maastricht University in the Netherlands, analyzed more than 88 studies.

This allowed them to conclude that training greatly improves cardiorespiratory capacity (or endurance) and muscle strength: two skills essential to maintaining good health, regardless of weight status.

Finally, Eliana Carraça and Jorge Encantado, from the University of Lisbon (Portugal), found on the basis of the results of 36 studies that exercise improves health-related quality of life.

People who are overweight and obese declare that, after a few months of training, their state of health has less negative impact on the quality of their life.

What physical activity to recommend?

Each type of physical activity has its strengths: strengthening benefits muscles, endurance helps weight control, etc. © Polina Tankilevitch / Pexel

Different types of exercises can be recommended depending on the need.

Moderate intensity endurance (walking, cycling, swimming, etc.) to promote weight loss and the maintenance of lost weight, loss of visceral and intrahepatic fat and to lower blood pressure.

Muscle strengthening (performed with weight machines, weights, elastic bands, etc.) is recommended to reduce the loss of muscle mass during weight loss.

The combination of endurance and muscle building is helpful for its effects on insulin sensitivity, fitness, and quality of life.

Our “PHYSICAL ACTIVITY” file

High Intensity Intermittent Training (HIIT) consists of alternating very intense efforts of short duration and periods of recovery of equivalent duration.

It is as effective as endurance exercise for weight loss, provided the energy expenditure is equivalent.

Please note, this practice must be preceded by a cardiovascular evaluation and should be performed under the supervision of a professional.

In summary, the practice of physical activity is strongly recommended for people who are overweight or obese.

Even if its effect on weight is limited, its many benefits on eating behavior, cardiometabolic health, physical condition and quality of life make it a valuable ally.

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This analysis was written by Alice Bellicha, Senior Lecturer in Nutriomics (Sorbonne Paris Nord) and Jean-Michel Oppert, University Professor-Hospital Practitioner (Sorbonne University) and Head of the Nutrition Department at Pitié-Salpêtrière Hospital.


The original article was published on The Conversation website.

Declaration of interests

  • Alice Bellicha does not work, advise, own shares, receive funds from any organization that could benefit from this article, and has not declared any affiliation other than her research organization.

  • Jean-Michel Oppert has received funding from the ANR (National Research Agency), INCa (National Cancer Institute), the European Commission.

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