Weight loss relies on an energy deficit, but the way to create it determines whether the result will be sustainable or followed by a rebound. The recommendations from HAS, updated in 2024, now include weight stabilization as a legitimate therapeutic goal and emphasize a medical, psychological, and social assessment before any nutritional intervention.
Preserving muscle mass during weight loss: the underestimated parameter
An improperly calibrated caloric deficit leads to muscle loss, which slows down the basal metabolism. The direct consequence: the body burns less energy at rest, making weight regain almost systematic upon stopping the diet.
HAS explicitly recommends preserving muscle mass through strength training combined with a moderate reduction in intake. A program that combines resistance (dumbbells, bands, body weight) and sufficient protein intake limits this loss of lean tissue much more effectively than caloric restriction alone.
Strength training acts on two levers: it maintains resting energy expenditure and improves insulin sensitivity, which reduces carbohydrate storage as fat. We recommend at least two weekly sessions targeting major muscle groups (thighs, back, chest), even during a caloric deficit phase.
To complement this approach with suitable supplements, the weight loss section on Pharmanco brings together formulas designed to support a structured dietary rebalancing.
Personalized caloric deficit: why standard restriction fails
Fixed-threshold diets (like 1,200 or 1,500 kcal per day) ignore individual variations in metabolism, body composition, and physical activity level. HAS discourages very restrictive approaches and favors a moderate and personalized reduction in intake.
An overly aggressive deficit triggers adaptive mechanisms: decreased thermogenesis, increased ghrelin (hunger hormone), and decreased leptin (satiety hormone). These hormonal adjustments explain why hunger becomes unmanageable after a few weeks of a drastic diet.
How to calibrate your deficit without obsessive counting
Rather than counting every calorie, three concrete dietary levers can create a moderate deficit:
- Increase the proportion of vegetables in each meal, which reduces overall caloric density without decreasing the volume ingested or satiety
- Prioritize proteins (lean meat, fish, eggs, legumes) for their thermogenic effect and their superior satiety power compared to carbohydrates and fats
- Replace refined starches with low glycemic index sources (legumes, whole grains), which mitigates insulin spikes responsible for storage and cravings
This approach produces a natural deficit, without a permanent sense of deprivation, and integrates over time into a normal diet.
GLP-1 analogs and weight loss: strict medical framework
Since June 2025, the ANSM allows any doctor to prescribe certain GLP-1 analogs indicated for obesity, in accordance with their marketing authorization. These treatments (tirzepatide, semaglutide) act on satiety receptors in the brain and slow gastric emptying.
Their prescription occurs in addition to diet and physical activity, usually after the failure of nutritional management. The prescription authorization does not mean automatic reimbursement: financial coverage depends on specific criteria and is not guaranteed for all indications.
What these medications do not replace
GLP-1 analogs do not exempt from dietary rebalancing. Without changing habits, stopping the treatment often leads to weight regain. Their role is to facilitate adherence to the caloric deficit by mechanically reducing hunger, not to replace an appropriate diet.
They are part of a care pathway for obesity, not an aesthetic weight loss approach. The HAS 2024 guide emphasizes this distinction by recommending a graduated management based on the complexity of the situation.
Hydration and food chronobiology: two underutilized factors
Water directly participates in lipolysis (fat breakdown). Insufficient hydration slows down this metabolic process. Drinking before meals also reduces the volume of food ingested through a mechanical effect of gastric filling.
Food chronobiology, less publicized, shows that the timing of meals influences metabolism as much as their content. Meals taken late in the evening, when insulin sensitivity decreases, promote more storage than the same foods consumed earlier in the day.
Structuring meals without excessive rigidity
- Concentrate the main caloric intake at breakfast and lunch, when metabolism is most active
- Space meals four to five hours apart to allow for a complete drop in insulin between each food intake
- Reserve dinner for low-calorie density foods (vegetables, lean proteins) and avoid fast carbohydrates in the evening
These temporal adjustments do not require changing overall quantities, only their distribution throughout the day. Combined with a moderate deficit and strength training, they provide a solid foundation for gradual and sustained weight loss.
Weight stabilization, recognized by HAS as a clinically relevant outcome, deserves as much attention as the active weight loss phase. A body that does not regain lost weight after six months validates the quality of the chosen method, much more than the speed of initial loss.
