When the sunny days come, the desire to ditch the sweaters and covering clothes returns. A desire that – under societal pressure – is accompanied by the idea of showing a body, if not perfect, at least compatible with the norm shown in magazines and where filiform reigns.
The purpose here is not to revisit this observation, its causes and its physiological or psychological harms, supported by a large number of publications for several decades, but rather to specify the health risks of weight loss diets induced by a great physiological stress be induced, itself followed or accompanied by psychological stress… and ultimately, in almost all cases, (re)gain weight.
In fact, the subjective idea of body image usually determines the choice of diet, and the goal is not necessarily compatible with maintaining health: According to a nationwide survey, 45% of women who are not overweight are 15% of people who are thin (BMI under 22). followed a diet during the year, according to a 2011 opinion from the National Agency for Food, Environment and Occupational Safety (ANSES), based on an INCA study.
How does a diet work
Weight loss strategies consist of creating an energy imbalance through dietary restriction in order to release fatty acids from adipose tissue. However, things rarely go as planned.
The first illusion is the observed initial weight loss…which is only related to the consumption of hepatic and muscular glycogen, in this case our fairly readily available energy store in the form of carbohydrates, and the excretion of water bound to it (9 grams per 1 gram of glycogen).
Then the desired effect occurs: fat reserves are mobilized. What is generally less known, however, is that our bodies develop strategies to resist this weight loss.
With fewer available energy reserves (which we lost first), our body goes into “conservation mode” (with a drop in resting metabolism): leading to fatigue and feeling cold – thermogenesis (heat production) is reduced – which kick in when the limitation persists.
maintain muscle mass
Another (nasty) surprise is muscle wasting. Even with a qualitatively balanced diet, the loss of fat mass (75%) is accompanied by a loss of muscle mass (25%).
However, muscle mass plays a key role in resting energy expenditure and is a major contributor to thermogenesis and therefore resting energy expenditure. When there is less muscle, resting energy expenditure is actually reduced…
In order to maintain weight loss over the long term, it would then be necessary to further reduce food intake or increase energy expenditure. This is where physical activity plays a big role, well beyond its effect on energy expenditure during exercise.
Physical activity beyond calories
Beyond calorie consumption, the physiological effects of physical activity are at the beginning of a positive cycle: muscle mass is largely preserved at the beginning of the use of energy substrates. Because the more physically active you are, the higher the heat dissipation – even when you are at rest.
Its practice is also involved in the regulation of glycemia (blood sugar levels) and hormone and energy metabolism.
And if the hypothesis of its anorectic effects (appetite suppressant) is currently being investigated, its role as a regulator of food intake is beginning to be well documented: as a regulator of mood and response to stress, it would affect nutritional behavior, partly under the influence of these two factors .
Assessing the health risks of weight loss diets
In 2011, for the first time in the history of health risk assessment in this area, fifteen diets were examined by ANSES. They all had common consequences. An energy restriction through controlled food intake and the renunciation of at least one food category lead to deficits in certain minerals, vitamins, roughage or excess proteins, sodium… , hormone balance, bone status, kidney and liver function.
All restrictive diets, by their very nature, actually lead to nutritional imbalances.
There is also a paradox: the sometimes spectacular short-term effects of these diets hide the major health risks and the almost systematic weight gain – in 80% of cases a year after the diet and in 95% of cases within a period of time. of five years. This observation makes it a public health issue that will still be relevant in 2022.
Sure, because the weight loss diet is experienced as a temporary measure, this effect shows. It becomes a staple, although it could be the gateway to an eating behavior that could perpetuate the restoration of nutritional balance or even an improvement in metabolic, cardiovascular, and psychological parameters.
However, the compulsion creates psychological and physiological stress that only a few can withstand in the long term. In this context, physical activity and a well-considered diet find their place in order to maintain health over the long term and to prevent persistent weight gain.
Understand the origin to accompany above all
Obesity, when it really exists, can be caused by poor diet, lifestyle, stress, lack of exercise, age, metabolic and/or hormonal imbalances… Once the triggering or maintaining factors are not identified, the fight against obesity begins in.
Diagnosis and individual follow-up by a health professional – nutritionist, nutritionist – are therefore essential to understand the origin and then control the health consequences of nutritional imbalances.
In fact, the restrictive diet cannot be adapted to thousands of people. If the initiative is individual, the accompaniment must also be individualized. Dietary practices, compatibility with lifestyle, and personal history are critical points to support the desire for weight loss, which, to be truly satisfying, must have mental and physical health as the primary goal.
Normally, the brain responds to a drop in energy reserves by sending out hunger signals. The restriction and control of food intake then comes into conflict with physiological needs: permanent control will ultimately disrupt the transmission and interpretation of hunger, satiety and satiety signals that regulate eating behavior.
The harmony between nutritional needs and food intake is disturbed, permanent and partially permanent. This break is the origin of eating disorders, but also of post-diet weight gain, which has been documented for several decades.
If restrictive diets are practiced without identifying the causes of excess weight, the loss of pounds is followed by their recovery. So, with the restriction-induced decrease in energy metabolism, eating so much leads to weight gain beyond baseline… Which in turn leads to repeat dieting.
This phenomenon is the origin of the yo-yo effect, with a peak that increases after each episode. Those restrictive diets sold for weight loss are the root cause…of weight gain. To prevent it from setting in, physical activity is a very good defense that acts as a regulator in many ways through the physiological and psychological role it can play, which is well documented.
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